[Sca-cooks] A different "Fresh Cheese" question

[Dragon]

Terry Decker wrote:

>So the question is. what is the science behind the different textures?
>
>Euriol
>
>I can't tell you precisely what is happening, but I can point out 
>the likely differences.
>
>Rennin is an enzyme, that in an acidic environment (such as that 
>created by lactobacilli) catalyzes the coagulation of casein.  As I 
>understand it, this is a slow conversion process that merely 
>accelerates the natural curdling of milk beyond sour cream and 
>yougurt to the more solid cheese curd.  Rennin enables and enhances 
>the conversion, but is not bound up in the process
>
>Vinegar is acetic acid.  Strong acids "cook" proteins, causing them 
>to coagulate.  Acids produce a lot of hydrogen ions and I suspect 
>that the coagulation occurs because the hydrogen ions combine with 
>the soluble protein, but I don't have any texts to hand that would 
>clarify the point.
---------------- End original message. ---------------------

I believe Bear is essentially correct with this summary.

A few more comments:

The amount of acid needed to curdle a given quantity of milk for an 
acid set cheese is not a constant. You can't just measure some amount 
and add it to the milk and expect it to work every time. Milk, lemon 
juice and even vinegar are variable products and you need to add 
enough acid to produce full coagulation. How much is enough? It's 
pretty easy to tell, when you see the liquid go from opaque white to 
a pale, translucent yellow, you have added enough. This generally 
works out to about 1/4 to 1/3 cup of lemon juice when I do it but you 
really have to add it a little at a time and watch the reaction.

The temperature for making an acid set cheese should also be about 
165F to 175F, at this temperature range, the acid performs best to 
cause all of the proteins and milk fat to form curds. Below this 
range you do not get complete conversion, above it, you start to 
damage the curd.

Don't use junket, it is really weak and not a good choice for trying 
to make any sort of cheese. Get liquid rennet (animal derived is best 
but vegetable types work OK too).

When you use rennet, you still need to allow the milk to acidify 
prior to adding the rennet. If you do not, you will get very rubbery 
curds. The amount of rennet needed is also variable, the same break 
from white to pale yellow liquid is a good indicator of how much you 
should add. The acidification of the milk is most often done with a 
lactobacillus culture. These cultures can be ordered from a cheese 
making supplier.

Always stir in your coagulant gently. Too much agitation will break 
up your curds into tiny pieces.

Let the curds sit for at least 15 minutes, longer is better. This 
allows them to come together and be easily removed from the whey. 
Please note that if you use goat milk, all you will get is very fine 
curds, it simply does not set the same way as cow or sheep milk.

Get some butter muslin. Especially if you are going to do goat 
cheese. It is much finer weave than cheesecloth. And while we are at 
it, buy your cheesecloth from a cheese making supplier, not a grocery 
store, the difference in quality is worth the extra price. The better 
stuff is washable and reusable for a long time, the cheap stuff will 
fall apart and leave lint in your cheese.

As for the specifics of temperature, cultures to use, maturing times, 
molding, aging, etc. I really suggest getting this book which has 
some excellent information and a lot of recipes:

"Home Cheese Making" by Ricki Carrol (ISBN 9781580174640)
http://search.barnesandnoble.com/Home-Cheese-Making/Ricki-Carroll/e/9781580174640 


Dragon

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