I have looked at various recipes and many require buttermilk instead of reg milk. Which is better for cake recipes? I know buttermilk cost more, but I want to make sure that my cakes are very moist.
It totally depends on the recipe. I've occasionally substituted milk in recipes that called for buttermilk and haven't really noticed a huge difference. Others may beg to differ. However I always keep a canister of powdered buttermilk in my frig just in case......I live far out in the middle of nowhere so I can't just run to the grocery store.
I too keep dry buttermilk in the refrigerator because the acid in buttermilk can make a major difference in certain recipes. Some recipes have a sour milk alternative which is just lemon juice or vinegar combined with regular milk. I believe that it has to do with the chemical reaction with the leaveling agent, i.e. baking soda, baking powder.
The follow site explains some of the science involved. http://homecooking.about.com/od/foodequivalents/a/buttermilkequiv.htm