Originally Posted by tdejarnette
I have a recipe that calls for sour milk or buttermilk. In the past I have soured milk with lemon juice. I actually have some real sour milk (dated August 19) Can I use that? It is a cookie recipe BTW.
Actually - unless the milk is whole RAW milk straight out of the cow (not pasteurized or homogenized or processed in any way) what you have is probably not sour milk, it is spoiled
Sour milk is fermented by lactic acid bacteria and gets thicker like yogurt or sour cream. This bacteria that causes milk to "sour" is killed when it is pasteurized. That's why if you want to make yogurt at home (using milk off the shelf at the grocery store) you have to add the narutally occuring lactic acid bacteria back into it.
While not the same texture ... buttermilk has a similar taste - adding lemon juice or vinegar to fresh milk from the grocery store also gives a similar flavor. Adding acid to milk will give it a sour taste - but not the same flavor or texture of natural fermentation.
Originally Posted by TomW
For the microbioligists out there, remember that as long as sour milk is used in a dish requiring high heat (such as biscuit), any "bugs" will be killed off by the heat.
Tom, those bugs in sour milk are good for us! Although I'm not so sure about the bugs in spoiled milk.