I once read, as a child, that you could take pure milk, put it in a burlap (or something) bag, carrying it around, swinging it,in hot weather, and it would turn into cheese.
True?
If you put milk in a burlap bag, you’ll have a wet, empty bag and a lot of milk on the floor.
That said, fresh cheese (like ricotta, etc.)and yogurt are just milk with some kind of yeast or other curdling agent added. No shaking is required.
The key thing though, is that you don’t want other types of bacteria getting into the act. If that happens, you just have spoiled milk, which, as you might know, is not tasty.
It also doesn’t work if the milk has been pasteurized. The bacteria which ferment the milk into cheese are killed by pasteurization along with any bacteria which could have made someone sick. Every silver lining has a cloud, as they say. Commercial cheeses are made using pasteurized milk and cultures of the bacteria that would ordinarily have fermented it, which have been carefully kept pure of any potential contaminants. This same basic method is used to make sour cream, buttermilk, yogurt, and other dairy products of that kind. When you see a package of (eg.) ‘cultured sour cream’, the ‘cultured’ at the front means that it was made using pasteurized cream and bacteria cultures rather than in the traditional way of letting unpasteurized cream naturally go sour.
Actually cheese is usually made from pastuerized milk, and bacteria is not the primary curdling agent, an enzyme called rennet is.
Our esteemed moderator JillGat has addressed this issue: http://www.straightdope.com/mailbag/mrennet.html
I made cheese once (when I was a child) using just rennet and milk. After adding the rennet to the milk, the milk separates into curds(milk solids) and whey, the liquid. This is also known as cottage cheese. The whey is then pressed out by placing the proto-cheese in cheesecloth, draining the curds, then pressing the curds to get as much of the whey out as possible and aging the cheese. If you just use pasteurized milk and rennet, you get a very bland cheese. It also takes a long time (not good for an impatient child) This is much as I actually know about cheesemaking. I suspect that the different types of cheese come about by the addition of bacteria, which are usually somewhat localized, but could be exported, so you can buy Wisconsin swiss cheese.
It sounds like vanilla has gotten a synthesis of the story of how cheese was invented, combined with using cheesecloth (which looks like burlap in miniature). The story I have heard of the origin of cheese is that a shepard or hunter stored milk in a container made of a (sheep, goat, calf) stomach, and when he went for lunch, found a tasty new dish instead of the milk he expected.
Probably more than you wanted to know: http://www.efr.hw.ac.uk/SDA/cheese2.html
Zyada, yes! That was the story.
In my son’s calss, he said they made “cheese”. I doubt they swung it around in a cows stomach though.
That would’ve been cool…
Zyada-yes, rennet is a major curdling agent, but you also need a bacteria culture to get real cheese. From the SD Staff Report you linked to:
“The cheesemaking process varies some with the type of cheese, but all basically use the same method. Milk is heated (pasteurized) to destroy harmful bacteria, then cooled and a starter culture of bacteria that produces lactic acid is added to start the coagulation process. Next, for most types of cheese, rennet is added to speed the coagulation and separate the milk into solid curds and liquid whey.”
Note the ‘starter culture of bacteria’. You can actually make cheese without the rennet, but it takes a lot longer & the results are not as good … without the right bacteria, the milk will spoil rather than sour, and I highly doubt it would be edible.
The particular type of bacteria in the culture are a major factor in the flavor of the final product. Producers in the U.S. make cheeses and yogurts of types traditionally based on goat, yak, mare, or camel’s milk using cow’s milk instead, introducing bacteria cultures of types ordinarily not found in cows.
Cheesenet:
http://www.wgx.com/cheesenet/index.html
and
You can even make cheese just by adding an acid (say, lemon juice) to milk. That curdles it, then you drain it with cheesecloth.