We are very fond of sour milk pancakes, and have
often had to go without any in the winter when the weather was cold, just
because the milk would not sour. I have learned to put a teaspoonful of
vinegar in a pan of milk, that I wanted to use for the cakes the next
morning, and find that it never fails me in making the milk sour. Placing
the pan over the register for the night helps matters along.