cc  >> Cathy Vrentas: Hi, everyone.  Welcome to Wednesday Night at  the Lab.  So even though usually I  introduce the speaker, today I  am the speaker.  I'm going to be talking to you  about the science behind  Wisconsin foods like beer and  cheese today.  So I'll just give you a little  information about myself to  start with and then we'll get  going.  And the way it's going to work  today, as some of you noticed,  we have a cheese tasting set up  in room 1360.  So I'm going to talk for the  first part.  We'll have time for a few  questions then we'll get us  going on the cheese tasting, and  if you have further questions  feel free to ask me while we're  enjoying the cheese.  But there should be plenty of  cheese.  >> Is there beer?  >> There's no beer today. 

 (laughter)  Just cheese.  I don't know about the beer on  the university expense account  but the cheese, the cheese is  okay.  We do have quite an array.  And I'm going to be telling you  a little about the cheeses and  also when we go over there we'll  talk a little bit more about  them.  But we will talk about both beer  and cheese as well as sauerkraut  tonight.  Just a little bit about myself  since we're filming this.  My name is Cathy Vrentas and I'm  the outreach specialist here at  the UW Biotechnology Center.  I got my PhD  from UW Madison in December 2008  in working in a microbiology  lab.  So I wasn't studying microbes in  food production but while I was  in graduate school I got very  interested in this and along  with my friend, Laurel Norris,  we cosponsored with the Alumni  Association a series of beer and  cheese tours of Green County.  So that was a lot of fun. 

 We went down to Green County,  I'm going to show you some of  the pictures today in our  PowerPoint touring some of the  cheese and beer factories down  there.  So that was a lot of fun talking  to people about the science  behind beer and cheese so I'm  going to share you with today  some of the things that I've  learned about the products and  as I said maybe just a little  bit about sauerkraut at the end.  But I think it's perfect  considering it's Wisconsin.  If I move I might have to modify  my talk a little bit.  But I'm quite a fan of both beer  and cheese.  And just a little bit about  cheese in Wisconsin to get  started.  So I thought this was pretty  interesting.  If you go to the Milk Marketing  Board they have some pretty  interesting statistics on their  website.  So I would have thought the  United States would have been a  little higher, but it turns out  Greece, in terms of per capita  consumption, has the highest  cheese consumption.  We're pretty high. 

 We eat quite a bit of cheese  here in the United States.  And actually US cheese  consumption has been going up  considerably, and I'm sure some  people have looked at why that  is.  I'm not 100% sure about the  trend.  Maybe some cheeseburgers, I'm  not sure, but certainly been  increasing.  And if we look at what types of  cheeses we're making, so today  we're going to be tasting a wide  variety of cheeses.  So predominately we see  mozzarella and cheddar cheese.  So you can imagine mozzarella, a  lot of these cheeses, we're  looking at processed cheeses as  opposed, or mass production as  opposed to artisan cheeses which  I've selected mostly today but  you can imagine the cheeses on  top of your pizza account for a  lot of cheese consumption.  And also cheddar cheese on a lot  of sandwiches and American type  cheeses and then a variety of  other cheeses.  And so you've probably seen, so  there's all the discussion about  the happy cows in California and  concern about California  surpassing Wisconsin, but  actually Wisconsin still remains  slightly higher than California  at least in terms of the 2007  data in terms of cheese  production.  And what is also true is that  Wisconsin is well known for its  artisan cheeses and highly  crafted cheeses. 

 So Wisconsin has a series of  master cheese maker classes that  people can take to become  certified as master cheese  makers.  So Wisconsin cheeses  consistently win awards in terms  of quality.  And there's a variety of other  high cheese producing states.  So Wisconsin, California for  sure, New York is another big  cheese producing state.  It used to be very large in the  nation.  Wisconsin actually back in the  day was starting to be known for  its milk and cheese production  but some of you may have heard  of the Babcock butter fat test.  That really helped get things  going in terms of Wisconsin  being known for cheeses.  So Babcock Hall makes ice cream  and cheese, and we actually have  some Babcock ice cream here  today.  So Babcock at the University of  Wisconsin Madison was able to  develop a test to measure the  amount of fat in milk.  And this was important because  Wisconsin cheese makers could  use this test when they're  coming and had their milk they  could test and they could really  prove that they had high quality  milk. 

 It wasn't adulterated, it wasn't  watered down with other  substances.  So it really got the Wisconsin  dairy industry going.  And as you can see Wisconsin is  at the top in terms of cheese  production, and a variety of  other states produce a lot of  cheeses and you can pretty much  find some cheese making  everywhere.  So I'll get started on my talk  here about cheese production but  this is one of the photos I was  telling you about from our  cheese tour we took a couple  years ago.  We went down to Roth Kase in  Green County so that's my friend  Laurel who's running the tour  next to it.  And you can actually schedule  some tours, I believe.  You can see what they're doing  in terms of seeing their cheese  production there.  So that's something to check out  and I can show you their website  or tell you more about that at  the end here.  But we had a really good time  touring their factory.  Oops, I kind of canceled out  here. 

 We'll get that started again.  There we go.  So this is just a picture.  They have a little cheese store  where you can buy a lot of their  cheeses.  And actually today I have a  couple of selections from their  cheese factory.  That's not what we want to be  doing.  There we go.  So there's a picture of me  serving some cheese at Roth  Kase.  So just to get started thinking  about making cheese.  First of all, we obviously start  with milk. 

 So thinking about what's in the  milk and what are we getting  started with.  Well, we certainly have  proteins.  We have casein which is a major  protein that will come into play  here in a second.  We also have whey protein, so  think about curds and whey and  little Miss Muffet.  We have water, a large  percentage.  We have fat.  And you can make cheeses with a  variety of starting fat content.  So whether you're using full-fat  milk or skim milk you can make  the same type of cheese.  Certainly the amount of fat will  affect the cheese.  We also have sugar, we have  lactose so it's milk sugar. 

 We have variety of vitamins, and  depending on if you pasteurize  the milk or not you can get  different tastes.  So in Europe especially a lot of  the cheeses are made with raw  milk.  So some of the cheeses here can  be made with raw milk but they  have to be aged for several  months.  I think it's a 60 day limit for  them to be sold in the United  States.  So there are some French cheeses  and other European cheeses that  cannot be imported.  So how the milk is treated to  heat it, to kill microbes, so  certainly the pasteurization,  the goal is to kill harmful  microbes to prevent us from  getting sick.  But how the milk is treated can  really affect the quality of  your cheese.  So there's different ways that  it can be heated.  It can be heated for a longer  time at a lower temperature.  Or it can be heated at a higher  temperature for a shorter time. 

 Heating at that higher  temperature is often used for  mass cheese production but that  harms the flavor of the milk and  the subsequent cheese.  Another thing that I think is  really interesting is the exact  species of grasses or other  plants that the cow, the goat or  sheep, because certainly keep in  mind not all cheeses are cow  milk cheeses.  We're going to have some  examples today from goat milk  and sheep milk.  But the species they've been  feeding on can actually have an  affect on the cheese taste.  So they did a really interesting  study.  I have a book called Molecular  Gastronomy which is a  fascinating compilation of  little mini essays about  different types of food science  topics, and they have in one  essay they're comparing cheeses  from cows, I think it was either  cow or goats that were grazed on  one side of a hill versus  another.  So it was the same hill but one  side or the other.  And they had different types of  foliage on the sides of the hill  depending on which side faced  the sun more, and they were  actually able to tell  differences in the taste of the  milk.  So even though those small  things like what the animal has  been eating can affect the taste  of the milk and the subsequent  cheese.  So you can imagine too if you're  making cheese from an animal  that has been grass fed or fed  in the pasture versus been fed  during the winter like on some  stored products or silage or  things like that that might also  affect the quality of the milk  and the subsequent cheese. 

 And I thought this was pretty  interesting.  If you think of processed cheese  you think orange.  Bright orange.  So that's done by adding color.  So -- for example is one color  that makes yellow or orange  cheese.  But it turns out the reason I  think they selected the orange  is because traditionally some  cheeses would be slightly orange  so if you had a cow that was  grazing on green plants and  other types of fresh plants out  in the pasture, those would have  vitamins like beta carotene and  vitamin D and those would lead  to slightly orangey or yellow  color to the milk.  And then the milk that was made  from that, so if they were  eating that in the summer, the  milk that was made from that,  maybe say in the winter, would  be slightly orange or yellow.  So whereas in contrast, if you  had a cow or a goat that was  grazing on some sort of  processed or stored product or  silage in the winter, the cheese  you might make from it in the  early spring wouldn't have that  same color.  So that's kind of an interesting  thing.  So certainly the quality of  cheeses can vary a lot by what  you're starting with as a milk  product. 

 So I'm just going to go through  a little bit in terms of the  steps in cheese production.  So there's three steps.  I'm going to come back to the  slide as we go through them.  But the first step is really  cheese.  So we're starting with a liquid,  milk.  We need to get to a solid,  cheese.  How do we do that?  And the second thing, we made  the curds.  So the first step, we're making  those cheese curds.  So you can eat them.  That's certainly tasty, but how  do we make those curds into  cheese?  So step two is concentrating the  curds, so removing the liquid. 

 Again we'll go into that in more  detail.  And then step three is, really  determines why we have such an  array of cheeses.  So in the room I'm going to have  for you with the cheese tasting  I'm going to have maybe ten  different types of cheese.  Why do all those different types  of cheese have different smells,  different tastes, what about the  processing allows for that?  And the difference is the way  they're aged and what other  types of microbes are added.  So we're going to talk about  that in a little bit here.  So just want to show some  pictures.  So we're getting started in the  first part here.  Looking at adding what's call  the starter culture and the  rennet.  So you might have your milk,  your milk will come into the  cheese factory, and one thing  they'll do is they'll definitely  test for the presence of harmful  microbes and make sure your milk  is safe.  And then they'll begin  processing. 

 So they'll have large, you can  see the large tubs of milk  depending on the size of the  factory.  And what they're going to be  adding is something called  rennet or something to that  called chymosin.  So I'm going to talk a little  bit about that.  So there's two things.  We'll start with the rennet and  then we'll move on to the  starter culture.  So chymosin is an enzyme that  causes milk to curdle, to form  the curds.  So you hear about the curds and  the whey.  So this enzyme can cut apart  some of the proteins in milk.  The casein proteins, so one of  the types of protein.  And they form big globs with the  calcium that's in the milk. 

 So the next time you think about  cheese curds it's actually  calcium phosphocaseinate.  So you can think about that,  that's really what you're  eating.  But what happens is those globs  form in there, so you've got  these big cheese curd globs, and  there's other liquid around  there.  It contains other things which I  have other proteins called the  whey proteins.  One thing that's interesting is  that, so this enzyme chymosin is  found in rennet.  So rennet was originally made  from the lining of calf stomachs  or in the case if you were  making goat milk cheese, you're  using the lining of goat  stomachs or kid rennet.  So now some cheeses are made  that way, but a lot of them are  moving to using a non animal  source of rennet.  So one example is there's some  vegetable rennets so some plants  actually naturally have an  enzyme that curdles the milk.  And fig leaves or thistle, they  can make rennet from those  sources.  And they also have, so tying  into biotechnology, we're in the  Biotechnology Center, you can  also make chymosin industrially. 

 So we actually do a little  example of this experiment when  we have groups visiting our lab,  and we use a huge big bottle of  chymosin.  And where that comes from is a  fungus.  So they've engineered a fungus.  They've put the gene in it to  make, so the DNA that will allow  the fungus to make chymosin, and  then they can produce that  industrially and use the  industrial chymosin.  But there are still some cheeses  that do use the animal rennet.  So a lot of times if you check  your cheese you might be  interested you can kind of see  sometimes it might say animal  rennet and a lot of times you  might see vegetable rennet on  your cheese.  So you can kind of check that  out and see.  So that's that first step in  terms of curdling, and there's  also another step in there that  also helps in terms of  solidification of the milk into  the curds.  So we're adding microbes here.  So the addition of microbes. 

 The microbes break down the  sugars, remember that lactose  that's inside of the milk.  They break that down and they  form acids and those acids also  curdle the milk.  So you can try this actually if  you have some milk at home and  you add vinegar you'll be able  to see some big chunks.  Now usually that's not what you  want to do but in the case of  cheese making you do want to do  that.  And so we talked about, so  microbes both streptococcus and  lactobacilli.  So they add those microbes to  the milk as the starter culture.  Now you can imagine whenever I'm  talking about any of this  production, whenever people were  making this back in the day they  were not adding a starter  culture.  Things were kind of naturally  souring.  So people figured these out by  microbes that were naturally  growing on the milk.  Nowadays, we do not let these  types of things to chance. 

 We're adding our very  well-tested vial of starter  culture.  We know exactly what's in it for  purposes of food safety.  But originally the milk soured,  formed some sort of cheese like  product, somebody tasted it and  at least some people survived to  tell the tale and they learned  how the steps of making cheese.  But when I talk about beer  you'll see that in the case of  beer people didn't realize that  microbes like yeast were  involved in beer production  until the late 1800s.  So a lot of times people were  making products but they really  didn't know exactly what's  happening.  And a big theme I want to focus  on today is a lot of these  products I'm telling you about,  so all the things, the cheese,  the beer and the sauerkraut, all  of these things are using  helpful microbes.  So we had a talk a couple weeks  ago about fungi and how some of  them can be bad disease causing  but some of them are very useful  and important in our ecosystem  or for humans in terms of making  products maybe through  biotechnology or other methods.  So microbes can be very helpful  as well in terms of food  production.  So if the right microbes are  growing, the right bacteria, the  right yeast, that's a good  thing, and that's helping us  make a variety of food products.  >> It has the streptococcus?  >> Cathy Vrentas: But not, so  there's different versions  though, so it's not a  harmful version, exactly. 

 It might be related to a harmful  species but it's not the same  exact type.  So it might not be the same  species.  It might be in the same grouping  but not the exact same species.  So the question is in terms of  the some of the species might  sound like they're related to  some more harmful bacteria and  they might be somewhat related  but they don't do the same  things.  So the next step is we're going  to concentrate the curd.  So we have these curds but  they're surrounded by liquid.  And that has some other proteins  in it, the whey, and we want to  get rid of the liquid.  And the amount to which we get  rid of the liquid affects the  cheese.  So a soft cheese, so if you  think about today we have some  examples we have Brie, we have a  farmer's cheese, so the softer  cheeses you're going to leave  more of the liquids inside the  cheese.  More firm cheese like a firmer  cheddar, more of the whey and  the liquid will be expelled. 

 So a lot of times, for example,  they'll come through so they'll  cut the curds so you might have  one big gelled up mass of curd  so you're going to cut them up.  And then you need to expel the  whey, get rid of it.  So some examples are the process  of cheddaring.  So here what they're doing is  they've combined the curds,  they've kind of knitted them  together and they're folding  them over and basically pressing  out the whey.  So they're going over and over.  That's called cheddaring.  Another thing they might do is  they might place the cheese into  molds.  So here and example.  I think this photo is actually  from Roth Kase.  They're putting cheese into  molds, and some curds actually  get cooked. 

 So they can make maybe a tighter  cheese, for example.  And a thing you can have is you  can have cases where they sort  of pull the curd and those are  cheeses called pasta filata  cheeses.  So think about mozzarella or  something like that, sort of a  pulled curd cheese.  And another thing they do is  they also add salt so that both  adds taste and it also has a  preservative quality so  preventing harmful microbes  growing.  So in all these cases what you  want to do is have the microbes  that are good growing but the  microbes that are harmful not go  growing.  So that can be done in a variety  of ways depending on the type of  cheese.  So in some cases if you see a  cheese factory you'll see little  cheeses floating around.  They're floating in big vats of  brine down the assembly line,  that's one way.  Or cheese can be rubbed on the  surface, or salt can be rubbed  on the surface of the cheese.  Or in the case of cheddar they  just throw salt on the cheese. 

 So there's a variety of  different salting processes.  And one think I wanted to tell  you that's kind of interesting  is that a couple weeks from now  so I guess it be will in August,  the first week in August, we're  going to having a talk that  focuses on whey protein.  So a scientist here, Denise Ney,  studies whey protein because  what's left behind is actually a  great diet for people who have  PKU or phenylketonuria.  So I'm not an expert on this but  she's going to be telling you  all about this.  So if that's something you're  interested in you can join us  here at the beginning of August.  So now we've talked about we've  got the starter culture and the  rennet.  We've got the curd that's been  concentrated.  So we have a cheese, you could  eat the cheese.  But at this point we want to do  things to sort of distinguish  the cheeses.  So I'm going to show you cheese  when we're in the other room, a  farmer cheese that's not an aged  cheese so it doesn't have a very  complex taste. 

 It's kind of a softer cheese.  But a lot of cheeses, think  about blue cheese or cheeses  like that, they have a very  strong taste and the reason this  is is you have the substances in  the cheese, you have the  proteins, the you have fats, you  have the sugars.  And what we do is we put helpful  microbes in to change those  compounds by breaking down those  compounds so it's basically,  sort of think of it as almost a  controlled spoilage.  We don't want to spoil the milk.  We sort of want to but in a very  controlled way.  We want the microbes to break  down those substances to release  things that smell good, things  that taste good depending on  probably who you're talking to,  different people like different  cheeses.  And you can get a very distinct  smell and taste.  So that's the aging.  And again the amount that the  cheeses are aged really depends  on the cheese.  So each cheese has a very  specific way of doing things. 

 So you'll put the cheeses into  rooms that have controlled  temperature, controlled  humidity, again depending on  which type of cheese you're  producing.  So I just wanted to talk to you  about a couple types of cheeses  to give you an example.  So one example is blue cheese.  This is one of my favorites.  So in this case the blue part  actually comes from molds of the  penicillium group.  So related to the molds that  produce the antibiotic  penicillin.  And there's some examples here.  So there's -- and my favorite  actually some of you may have  heard of Maytag blue.  It's pretty well known because  it comes from the Midwest.  Actually a town near Des Moines,  Iowa. 

 There's an interesting story  behind this.  So it's actually the people who  originally made the Maytag blue  were related to Maytag who  developed the appliances.  And it was his sons.  And they wanted to do something  as a business so they first  tried dairying and it wasn't  really what they had been hoping  for in terms of profitability.  So the story is they went to  speak to a professor at Iowa  State University and he  suggested try to do a sort of  unusual artisan cheese.  And he suggested blue cheeses.   So they got into the blue cheese  industry and they have their own  herd of Holsteins.  And they make Maytag blue, and  it's shipped across the country  from what I understand.  And so I actually have some  today.  We're going to be tasting so  it's a very famous blue cheese  and well known, many awards. 

 So in the case of Roquefort  actually there's a mold,  penicillium roqueforti, and it  was originally had been growing  on some loafs of rye bread and  those little crumbles were put  into the cheese and that allowed  the mold to be in the cheese.  So you can imagine again that  somebody, at one point, had mold  growing on their product and  they tasted it and it was good.  Now that doesn't mean that if  you have mold growing on your  cheese you should taste it  because it could be a harmful  mold certainly.  But in this case these are well  controlled again so we know  exactly what type of penicillium  mold we're adding to the cheese.  So what they'll do is they'll do  something called needling where  they make little holes in the  cheese and let some air through  the cheese and those little air  pockets the mold will grow  through the cheese.  And as I said, I actually have,  in addition to Maytag blue, I  have some blue cheese crumbles  and I also have a goat cheese so  starting with goat milk that has  a different type of penicillium  mold.  So you can kind of compare the  taste so depending on the exact  process you'll get a little bit  different taste.  So again what you're doing here  the microbes are converting  those proteins, fats, sugars in  the cheese to new chemical  compounds, so smell, taste,  texture, that makes all the  cheeses different.  So here's an example, I like  this picture because that's me  talking at one of the cheese  plants and there's one of the  cows there with a Swiss cheese  look.  So in the case of Swiss cheese,  you know that Swiss cheese has  holes and the reason is that the  bacteria, propionibacteria,  create bubbles in the cheese. 

 And they're breaking down  substances to make carbon  dioxide and that makes bubbles  of gas.  So you get Swiss cheese bubbles.  And then one of my favorite  cheeses is Limburger.  I actually have some today for  any brave souls who'd like to  taste that.  I do this presentation a couple  times and we always have people  tasting the Limburger.  But Limburger actually was once  more popular than Swiss cheese.  so Limburger is infamous for its  strong smell.  And what's really interesting is  that the way Limburger is made  is that they spray bacteria on  the surface of the cheese and  these are the same bacteria that  grow on your feet and cause them  to smell.  (laughter)  So the bacteria grow  on your feet, they break down  the substances in your skin and  they cause an odor while they're  breaking down the proteins in  the cheese and also creating an  odor.  And it's called brevi-bacterium,  and as a result you get this  nice interesting smell. 

 And what's interesting about  Limburger, I find, so it has a  very strong smell but the taste  is actually kind of more like a  brick cheese, it's not a very  strong odor.  But you can try that.  And another interesting thing  about Limburger is that  basically all the production of  Limburger in the United States  is in Wisconsin.  And for a long time I had  thought it was only made by the  Chalet Cheese Co-op which is  near Monroe.  But someone at my last lecture  told me they had seen some  produced somewhere else.  And indeed I went to Sentry in  Madison today and I was able to  get some from the Shullsburg  Creamery so it looks like they  also produce Limburger.  So that's the one I brought  today.  So it's pretty interesting but  there's also some famous lore  behind the Limburger cheese.  So the Historical Society I  think has some little snippets  about that.  But there has been some infamous  things in terms of there was a  battle with the post-master of  Iowa over shipping cheese from  Wisconsin to Iowa because the  Limburger smelled so bad and  they kept sending it back and  they had a post-master do a  taste off and he enjoyed the  Limburger so it was okay for it  to be shipped. 

 As you can imagine as this  cheese, so in the case of a lot  of the compounds that cause  cheese to smell, these are  called volatile compounds, as  the cheese gets warmer you can  smell it a lot more.  So I have cheese that's been  refrigerated but really this  cheese is designed to be a table  cheese.  So you leave it out and let it  develop its full taste and  smell.  And in Monroe, so in Green  County, there's actually  Baumgartner's there's a place  where they serve, and actually  when I was in Green County I had  one for Farm Tech Days, they had  Limburger cheese and onion  sandwiches.  You can wash that down with a  beer.  (laughter)  It's a tasty cheese.  It's an example of an  interesting cheese.  One thing I forgot to mention,  so you can imagine how do you  think that people first figured  out that they should put foot  bacteria on the cheese.  What they were doing to get rid  of the whey in the cheese is  they were stomping on the cheese  curds.  And the bacteria were being  transferred from the foot to the  curd. 

 Now that does not happen  anymore.  But when it was  originally made that's how the  bacteria got on to the cheese to  create that special type of  smell.  So you can imagine and that's  why I think it's so fascinating  a lot of these beer and cheese  production methods, we didn't  really understand microbes until  the 1800s so these products have  been made for many years.  So people were making the  products but not exactly knowing  what microbes were in them.  It's only later when they  figured out exactly what they  were adding.  So then you get a variety of  these different types of aging  and processing procedures you  get a variety of classes of  cheese and you can divide cheese  into a variety of different  categories.  Cheeses will fall into multiple  categories.  So I mentioned fresh cheeses,  they're not cooked, the curds  haven't been cooked and they're  not ripened.  So I have farmer's cheese as an  example today but you can also  get some Italian spreadable  cheeses.  Cases of soft ripened or bloomy  rind cheese. 

 I have Brie here today.  It's been surfaced ripened.  So if you ever see that little  white on the outside of the Brie  that's a fungus that's been  sprayed on to the surface of the  cheese, and what happens is  there's differences as you go  through Brie from the outside to  the center depending on how the  outside gets ripened and then  changes what's going on right  underneath the rind and the  middle, the middle's going to be  different.  It's almost like a chalkiness.  So there's differences in the  cheese depending on where you  are from the rind.  You have washed rind cheeses.  So in these cases you do  something to treat the rind.  You might be encouraging growth  of a certain microbe.  Changing things, for example,  you might use brine, might wash  with brine.  You might wash with wine. 

 You might change, actually I  found one from -- which I  brought in which has a chocolate  or a cocoa powder on the outside  of the cheese.  So whether that actually  encourages microbial growth, I'm  not sure.  It probably imparts some taste  quality to the cheese for sure.  But I'm not exactly sure how  that impacts the ripening of the  cheese.  We have natural rind cheeses.  So no washing, they're aged  longer.  I talked a lot about the blue  veined cheeses like the Maytag  blue.  Cooked and pressed cheese.  So again you have cases where  the curds have been cooked.  Something like a Gouda or a  parmigiano reggiano, and I have  a variety of harder cheeses here  for you to sample. 

 And then of course we have  processed cheeses.  So there's a variety of  possibilities.  You could have an American  cheese or you could have a  little single of cheese.  You have some things like cheese  food so in those cases you can  change the cheese by putting in  things like oils or emulsifiers  or basically things to help the  cheese be extruded in different  shapes.  Preservatives to let it last  longer, things like that.  So there's a variety of  different processing things that  can be done with cheese.  So what I'll be having today is  I'll be having a sampling of  different cheeses.  I've put out a label of each.  I've selected a variety of  Wisconsin cheeses.  There are a few that aren't from  Wisconsin like the Maytag  blue and I think the one, the  Brie is from France. 

 But a lot of them are from  Wisconsin cheese factories and  artisan cheese production  facilities.  So I think hopefully you'll  enjoy the selection.  I know I enjoyed it when I  tasted it right before.  But before we do our cheese  tasting I'm going to tell you a  little bit about beer.  So again no beer today but beer  is pretty fun because it's  another example of the use of  microbes.  So here we have yeast, and we're  using yeast to ferment.  So fermentation so that means  breaking down the sugars that  are in the starting material  which we'll talk about in a  second, and to produce, in this  case, the alcohol.  And so just a few pictures here.  So this is again from our beer  and cheese tour.  We were at New Glarus Brewery. 

 Some of the pictures from  inside.  They had a little audio tour  that you can take and a tasting  at the end.  So if you're interested in  tasting.  We also, on our second tour, we  went to the Minhas Brewery.  So this used to be the Huber  Brewery in Monroe and it's now  Minhas.  So changed over the last couple  years and they produce beers  there too and we had an  interesting tour there as well.  And some pictures that we took  from the outside of the brewery.  So thinking about again we  started with milk in terms of  the cheese as our starting  ingredient.  Well, what are we starting with  here?  Well, we're starting with water  and actually the water can  affect the taste quite a bit of  the beer.  So certain areas are famous for  a soft versus hard water. 

 So hard having a lot more  minerals, that could really  change the taste of your beer.  So some areas for example, a  certain brewery in  Czechoslovakia might be on this  one stream that has a certain  type of soft or hardness to the  water that's very distinctive to  their beer.  You also need that source of  sugar.  So what we want to be doing is  the yeast needs some sugar to  break down to cause the alcohol  to be formed in the beer.  And this case, the sugar comes  from what's called the malt.  So a lot of times beer is kind  of used to always think about  barley but you can also use  other types of sources and I'll  mention that in a second.  But you'll have barley seeds so  those are allowed to germinate.  And in the process of  germination you get conversion  of starch into sugar.  And then they toast the seeds in  a kiln and they can toast to  different amounts.  So in some cases you have more  of an amber color. 

 I'll show a picture in a second  here.  You might have a chocolate  color, so a little darker color  so the seeds will be darker,  impart a darker color, maybe a  stronger flavor.  And everywhere up to a very  black malt.  So something that almost gives a  bitter flavor to the beer.  A very dark colored malt.  And you can also have cases  Where they call crystal malt  where they bring the seeds up to  a high temperature very quickly  and therefore it causes  crystallization of the sugar.  And that can lead to a sweetness  to the beer.  So again, the darker the malt a  lot of times you get a more  complex flavor.  And actually you can stop by  they have a lot of stores that  sell wine and beer supplies and  you can check that out.  You can see, you can purchase  for not very expensive amount. 

 You can see the different  amounts of darkness.  You can look at an amber malt  versus a chocolate malt versus a  black malt.  You can check that out for  yourself.  And as I mentioned there's other  grains.  So in some cases in a mass  produced beer they might be  using things like corn syrup or  a malt extract or a rice or  something like that as a cheaper  source of sugar, but in a lot of  beers the other grains are an  important part of the beer.  So for example think about a  wheat beer, a lot of German  wheat beers.  There might be other additives  as well.  So some beers like Belgian beers  will have some orange peel  flavoring or a coriander.  So there are some certain  additives.  And I'll also talk about in a  second here is a fruit beer. 

 So there's some beer that also  have a fruit element to them as  well.  And then of course we have hops.  So hops were originally added to  prevent spoilage of the beer.  And later they became a flavor  additive.  So hops impart both flavor and  aroma.  So they cause that bitterness.  So originally it took a little  while for hops to sort of become  standard because there were some  other herbs that were used to  flavor the beer back in the  1600s and 1700s.  So some of the countries that  produced those herbs wanted a  monopoly on them, but eventually  hops became standard.  And so again they have these  acids in there, in hops which  I'll show you a picture here.  So this picture of the hops  plant. 

 So the hops are actually from a  flower.  This plant, the humulus lupulus,  I think I pronounced that wrong,  but I have actually known people  who have grown it and you can  actually see in beer gardens  they can grow the hops among the  trellises and things like that.  So those female flowers are  harvested and they're dried out  and then both the acids that the  hops impart as well as some  essential oils are what gives  both the bitterness and those  special taste and smell  qualities to the beer.  But again you think about that  spoilage angle it's always  important to avoid microbes that  you don't want growing in the  beer to be there.  So certainly you want the yeast  to be fermenting the beer.  And in some examples you want  bacteria as well but you don't  want harmful bacteria to  basically cause unwanted  spoilage.  So these are some of the things  that go into our beer  production.  So here's a picture, this is me  at the Minhas brewery.  They have a little gift shop and  they have some different  examples of some of the malts.  So I'm looking at one of the  lighter malts. 

 But you can see there are some  of the darker malts as well.  So we have the picture of the  hops.  And so really briefly the idea  here, so we'll start out, we'll  have our malt and the first  thing we want to do is get the  sugar out of the malt and into  the water so that the yeast can  break them down.  So the malt is mixed with hot  water so you can get the sugars  into hot water.  And then the resulting liquid or  the wart is moved into another  kettle where you add hops so the  hops can be added, and there's  actually cases where you can add  hops at several times during the  process depending on exactly  what flavors and tastes you want  to impart to the beer.  But then the hops will be  filtered out, and then you move  to a tank where you have  fermentation.  So I'll talk a little bit more  about this but what you're doing  there is you're adding the  yeast.  So that culture of yeasts and  the yeast are breaking down the  sugars and they're making the  alcohol in your beer.  And then you have processes and  it varies what type of beer.  You can have filtration. 

 Now some beers you can actually  see they're cloudy that would be  yeast remaining in the beer.  And some beers are what they  call conditioned or cast  conditioned so they contain the  yeast and they're continuing to  change the beer longer.  But in a lot of cases you'll  have filtration to remove the  yeast and pasteurization, other  processes, sometimes the beer,  especially lagers are left at  cold temperatures for a while.  So it kind of varies in the type  of beer.  So this is just a picture  looking at one of the tanks on  our tour of the Minhas Brewery.  And as I mentioned, so people  didn't know for a long time  exactly that it was yeast that  was fermenting the beer.  So probably the earliest beers,  if you think back to ancient  times, maybe on the Sumerians,  maybe what they'd be doing is  you'd have a piece of bread, you  could soak the piece of bread in  water and then you'd have some  of the sugars in the water.  And then natural yeasts and  fungi that fell in the water  could ferment the beer.  And it was actually good to  drink beer because, not that it  isn't now, but the water was not  a lot of times safe to drink if  it hadn't been treated.  So in this case the good  microbes would change the beer,  produce the alcohol and other  microbes wouldn't grow because  they're not tolerant of those  alcohol concentrations. 

 So those were some of the  original types of beer and they  probably flavor that with things  like honey, things like that.  But it wasn't until the 1800s,  so some of the earlier  scientists who were looking at  microbes were looking at things  in the microscope in beer, and  it was Louis Pasteur, who's  famous for a lot of his work in  microbiology and vaccines, that  discovered it really was the  yeast that was in beer.  And he discovered the process by  which the yeast were fermenting  the sugars to make the beer.  And he was able to actually make  some suggestions about beer  production based on that.  Figuring out what was going  wrong in some beer production  facilities because he understood  what was going on from a  biological level.  And there was actually two  different types, depending on  the types of beers you're  looking at, there's two  different types of fermentation.  So in the case of some beers  like ales, they're fermented at  warmer temperatures and the  yeast there basically called top  fermenting because they float to  the top of your fermentation  tank.  In contrast, things like lagers  you have yeast that go to the  bottom of the fermentation tank.  They're fermented at colder  temperatures and they're a lot  of times left to sit at colder  temperatures longer to sort of  mellow out the flavor.  So depending on the types of  beers that you're making you'll  have a different type of  fermentation process. 

 And then one of my favorites is  actually beers Lambic beer.  And there's a lot of examples  you could have in town.  So New Glarus actually makes  some Lambic beer, some  raspberry, some cherry.  And can you also get some  Belgian beer.  So Lambic beers are a classic  Belgian beer.  Some of them are fruit, some of  them are not.  And they originally made like a  lot of beers in monasteries.  So for a long time a lot of  beers are made in monasteries.  And what they would have, I'll  show you a little picture here,  they have a very large open tank  and they would have your  starting material.  And it turned out that the  location of these monasteries  were such that certain wild  yeasts and bacteria would fall  into the fermentation tank and  ferment the beer and they would  have certain tart flavor. 

 So in this case what you're  getting is in addition to the  yeast you'll also want some  bacteria.  Because the bacteria are making  the sort of tart tasting beer.  And in the case of a lot of  Belgian beers, they add fruit.  So for example -- is a  raspberry.  You get a very tart raspberry  taste.  So it's very interesting.  I enjoy them a lot and you can  also get them to cherry, peach,  different types.  But it's an example of both the  bacteria and the yeast  fermentation.  So a lot of Belgian beers are  the Lambic type.  So just to kind of finish up our  exploration of fermentation. 

 I did not provide sauerkraut  today.  Although I thought maybe some  people would like it.  I like sauerkraut but mostly on  other products.  But sauerkraut is another  Wisconsin food.  And it's another example of  fermentation.  So in this case so sauerkraut in  German is sour cabbage.  Again we're fermenting cabbage  or using microbes to change the  cabbage.  You're using microbes, there's  actually sort of a variety,  there's a couple of stages of  fermentation.  But the first microbes that  break down the sauerkraut, or  the cabbage in that case, so you  start with cabbage.  You break down the cabbage you  start producing some acids. 

 And a lot of microbes, a lot of  the harmful microbes, can't grow  in the acids but the ones that  you want growing will grow in  the acid and they'll convert  your cabbage into the sauerkraut  process.  So again a lot of these  products, so people can make  homemade sauerkraut but you have  for do it at just the exact  conditions of salt and  temperatures, things like that.  Because in all these cases what  you're trying to balance are the  helpful microbes that are  converting the foods into the  products that we like and the  those harmful microbes from  growing and spoiling the  project.  If anyone has ever made a home  brew and it went bad or  something like that, in that  case you're basically the  microbes you don't want growing  are overtaking the microbes you  do want there.  So those are some of the  examples of some of the foods of  Wisconsin that are made with the  help of helpful microbes.  So it gives you a chance to  think about helpful microbes  next time you're eating and next  time we're having cheese or beer  you can think about it in a  little bit different way.  So I think we'll take a few  questions and then we're going  to bring everyone to cheese.  As I'm sure everyone is eager to  have some cheese.  But while we're in the cheese   tasting room feel free to ask me  any questions that you have in  addition.  Yeah?  >> You've got another question  up there, are there helpful  benefits?  >> Cathy Vrentas: Oh, yes. 

 >> What am I missing not eating  sauerkraut?  (laughter)  >> Cathy Vrentas: I forgot.  That is very interesting.  A couple years ago this  actually came out, a story was  in the Wisconsin State Journal  about this, and it's based on  some research that was done by a  group of Asian scientists who  was looking at kimchi.  Those of you who've heard of  kimchi it's a very popular food  in Korea, and it's another  fermented product.  It's not quite the same.  It has cabbage but it also has  some other vegetables and it's  spicy, and in this case what  they found is that there was  some evidence that feeding some  of the kimchi products to birds  was preventing them from getting  the bird flu.  So there was some question, is  there a link?  So the idea was that Wisconsin  produces sauerkraut so therefore  it might be helping you against  the bird flu.  However, I would not go out and  stock up on cases of sauerkraut  unless you love sauerkraut.  But it maybe that there's some  useful products.  Actually, when I was reading  about the sauerkraut they say  there's a lot of healthful  benefits to sauerkraut in terms  of vitamins and other compounds. 

 It's probably healthier than  plain cabbage.  So definitely.  And they were, I think the study  was kind of looking to see if  this kimchi diet was affecting  people's health.  And they thought there was some  indications there.  >> Couldn't you get all the same  vitamin benefits from cabbage  and other similar vegetables in  that family?  >> Cathy Vrentas: Yeah, probably  in this cabbage and other  vegetables that were going into  it would have a lot of the same  compounds, although as the  microbes break things down that  might also change the compounds  that are inside the cabbage  because in each of these cases  the microbes are changing the  chemistry of the product.  So that might have some  additional health benefits if  those products are helpful.  Yeah?  >> Kimchi is not made out of  cabbage head it's made out of  like napa.  >> Cathy Vrentas: Okay, it's  slightly different.  So that might be also another  difference.  Maybe there's a difference in  what product, so the question is  in terms of kimchi made out of,  instead of being made out of  cabbage head it's made out of  things more like napa cabbage. 

 So it might be that the Kimchi  is not quite the same health  benefits as sauerkraut if it's  made out of a different starting  product.  It's one of those fun facts, and  I don't know I'll have to track  down that research to see if  anything more has been done with  it.  That was a couple years ago that  came out.  It was kind of interesting.  It made the headlines briefly.  Because it was right about that  time when bird flu was in the  headlines.  So it's kind of interesting.  Yeah?  >> In Steven Babcock's test, the  measure of the quality of milk  was the butter fat content which  is a way of detecting whether  the milk had been watered down,  as you said.  But today we don't necessarily  consider the high butter fat  content is high quality.  Is there one other standard or  lots of other standards that  have taken the place of butter  fat content as the way of  measuring the quality of milk?  >> Cathy Vrentas: So the  question was that  originally the Babcock test was  used for measuring the quality  of milk and now are there other  tests that have taken place of  the butter fat test. 

 Because, as you mentioned, in a  lot of cases we don't want high  butter fat.  Originally, as you were saying,  what was happening is people  were watering down the milk.  So by measuring the butter fat  content you could tell if the  milk had been adulterated or  watered down.  And that's a very good question.  I don't know in terms of plain  milk how people are judging the  quality of milk.  So certainly there's a lot of  variation in taste and I don't  know if there are any tests that  are being used to determine  differences in taste.  So certainly in the case of  cheeses a lot of what I've read  it's a lot of more tasting, and  what was interesting about this  Molecular Gastronomy book was  though they were starting to do  some analysis of cheeses though  to figure out what compounds are  in there.  Because for so long they'd just  been tasting and this tastes a  little different but everyone  has a different subjective  opinion.  So they were starting to use  chemistry methods to figure out  which compounds were in one  cheese versus another and maybe  compare cheese made with one  type of milk or another.  So I would guess that you could  use some of those same chemistry  methods to taste the milk. 

 But I'm not 100% sure.  So that's something I have to  look up in terms of tasting  milk.  I certainly know that when I  taste different types of milk  you can tell the difference  between certain, for example,  certain ones I've had that are  supposedly pasture fed and taste  very good.  So there's definitely taste  differences that probably stem  from the substances that they're  eating that are then changing  the substances in the milk that  would then affect the cheese.  So that's a good question.  Yeah?  >> When you eat Brie if it has  those little white dots of the  mold are you suppose to be able  to eat that or are you suppose  to cut it off and not eat that?  >> Cathy Vrentas: The question  with Brie, can you eat  the white dots of mold or not?  So in the case of Brie, the  outer rind, the white outer  rind, that's not harmful to you,  you can eat that.  In the case of most cheeses, the  rule is if you have a hard  cheese and you have a mold  growing on it, theoretically if  you cut the part that has the  mold on it off, you can eat the  rest of the cheese.  But if you have a soft cheese,  so if you have a Brie or -- or  something like that and you have  a mold that doesn't look like  the rind mold on it then you  should throw that away.  Because the soft cheeses the  little parts of the mold can  kind of spread through the  cheese.  So if it looks like the outer  rind that you started with,  that's fine. 

 But if you having a new mold on  it, you want to avoid eating the  new mold on a soft cheese.  I'm usually careful and I try to  avoid the mold, but in a very  hard cheese the mold is not  going to penetrate.  So you could cut off the healthy  part and then remove the moldy  part.  Yeah?  >> I was working in a milk  bottling plant in the '40s and  if a farmer didn't show up to  take the whey off the  butter-making churn it went down  the drain.  But I heard about a factory up  in Alto, Wisconsin, that makes  powdered cheese for cheese and  mac and I understood that they  were making it out of whey.  In other words, they're saving  everything out of even whey  nowadays, whereas if the farmer  came he could mix mash with it  and feed his pigs.  >> Cathy Vrentas: So you're  saying  about the production facilities  are using the whey protein.  That's definitely true.  If you look at your food labels  a lot of times you'll see whey  protein as an example.  It's a really good source of  protein. 

 I'm kind of interested to hear  that lecture in August to find  out more about the potential of  whey protein.  Because you're definitely  leaving a lot behind there.  There's a lot of good protein  there in the whey that's left  behind.  I believe there's also, I could  be wrong, she'll probably talk  more about that, there are some  beverage design here at UW  Madison where they're looking at  using some of the whey proteins  in like a Gatorade type of  beverage because it's good for  some high level athletes helping  replenish.  So I think there's some really  interesting things there with  whey.  >> I was also, we were adding  red dye to the butter in the  wintertime and I was wondering  today you hear about red dye not  being good for you.  >> Cathy Vrentas: Some people  have told me that  because we use food dye  sometimes at school and a lot of  people are allergic to red dye.  So that one seems in particular  people are allergic to it.  I don't know about all of the  health risks of each dye.  The dyes that are used are  thoroughly tested. 

 You can never be 100% sure.  The red dyes though definitely  are things that people have told  me that there is more allergies  to.  >> There is more than one kind  of red dye.  >> Cathy Vrentas: Yes, there are  different types of red dyes.  Yes, so I'm not an expert on  different types of red dye but  there's definitely a couple  different ones in the package.  Yeah?  >> I also used another product  and that's yeast and I  understand that powdered yeast  comes from the beer production  some place along the line and  you get B vitamins out of it.  >> Cathy Vrentas: So yeah, B  vitamins definitely from yeast.  If you go actually I think to  the Red Star Yeast website they  have a little thing that takes  you through some of the  production of yeast products,  and they talk about some of  those types of things,  definitely.  Very cool.  Yeah?  >> Are the unpasteurized raw  milk cheeses still sold in  Wisconsin?  >> Cathy Vrentas: So the  question is it about the  unpasteurized raw milk cheeses  are they sold in Wisconsin. 

 From what I understand if the  raw milk cheese is aged a  certain number of days that  prevents you from being harmed  because as they age you get rid  of any of the harmful microbes.  So there's rules in the United  States in terms of if the cheese  starts with raw milk then it has  to be aged a certain number of  days.  And a lot of times I think if  you can see on the package it'll  say made from raw milk aged at  least 60 days.  So in France, I'm not sure if  the rules have changed, but a  lot of the European countries  you can have the raw milk  cheeses and they're not, they  can be like the soft like the  Brie or the --.  So when you read books by cheese  connoisseurs they say that it  makes a big difference because  those raw milk cheeses have the  true flavor of the Brie and the  --.  But there's that risk if you  have some harmful microbes  because there's a lot of things  that can start out in raw milk  like Listeria or things like  that and you could get very sick  from it especially if you maybe  were a child or you had a  weakened immune system or things  like that.  So there's certain cheeses that  can't be imported into the  United States for that reason.  And I think when I was reading  about Limburger I also found out  there's some that are so smelly  that, there's one that's called  in French it's like the French  translation of the feet of God.  (laughter)  And you cannot import  that I believe because it is so  bad that it would be a hazard  for the smell.  So there are some interesting  products out there that you can  purchase. 

 >> I eat a lot of yogurt.  Is yogurt just another milk  product or is it a form of  cheese?  >> Cathy Vrentas: Good question.  So yogurt, there's a lot of  dairy products out there, so  yogurt, in the case of yogurt  you are using microbes.  So if you look on the side it  will say a lot of times a live  culture of a certain bacteria  like lactobacilli, and that case  the acid production is souring  the milk and causing  solidification.  So you're not adding the rennet.  Cottage cheeses, so a lot of  farmer or homemade cottage  cheeses might only use one of  the steps of solidification,  whereas the commercial made ones  are more of a true cheese using  both the solidification and the  rennet.  Butter milk is a case where I  believe that the cream is  removed and then what's left  behind is also soured by the  action of bacteria that are  producing acids.  So that would be another  fermented product.  And there's things like -- and  things like that.  So a lot of those dairy products  that have been changed have the  action of microbes. 

 And a big thing now is  probiotics.  So you might see the things that  say, I'm trying to remember some  of the brand names, but they say  they are good for digestive  health if you have certain types  of yogurt.  And the idea is in the case of a  probiotic, so if you imagine  back to one time you had an  antibiotic like penicillin a lot  of times you're killing the bad  bacteria that are making you  sick but also you're losing some  of the helpful bacteria because  my skin surface, my legs, inside  my body, I have lots of helpful  bacteria, and they're being  helpful by there's bacteria  coating my skin and it's  preventing other bad bacteria  from growing there.  So what happens is when you have  the antibiotics then you're  removing the good bacteria that  are just sort of sitting there  living along with you in  harmony, and it leaves some  openings there for bad bacteria  to grow.  So the idea of probiotics is to  prevent things like intestinal  problems or yeast infections  that arise from having  antibiotics by bringing in, by  the probiotic foods, helpful  microbes.  So their helpfulness I think, I  was reading the literature, it's  debated.  It depends on what you're  looking at.  So in certain applications  having a probiotic is helpful.  In other cases it's not quite  clear if it's helpful in that  sense.  But that's the idea behind a lot  of those yogurt products that  have been promoted is that  they're acting like what's  called a probiotic to give you  good microbes that prevent bad  microbes from growing. 

 So I think what we'll do is  we'll get started on our cheese  tasting, but please feel free to  ask me any questions that you  have and I'll do my best to  answer them.  I'm not a cheese expert, but I  do like cheese so I do my best.  So thanks everyone for coming  today.  (applause)