Homemade Yogurt

By Peggy Greb, USDA, Wikimedia Commons

Note: A friend gave me this recipe for making yogurt at home. It is actually pretty simple. Be sure to keep it warm enough during the incubation period so the yogurt will grow. I will try to make it again soon and add some pictures! ---

Boil Milk & Add Yogurt

Bring the milk to boil in a large container that you plan to leave the yogurt in as it grows. Try not to burn the milk, but sometimes it is difficult. You can make a whole gallon at a time if you like. Use skim or whole milk or goats milk ;) - whatever you fancy.

Let the milk cool to 122 F, and add a cup of store bought yogurt to the hot milk. In the future, you can also use a dollop of a previous batch of yogurt you made. The streptococci and lactobaccili that make yogurt from milk quickly ferment the lactose sugar in milk leaving lactic acid waste product that causes the pH to plummet and causes the milk protein to coagulate. Boiling the milk kills off nearly all potentially competing species of microbes. The low pH inhibits growth of species other than the desired yogurt bacteria.




Incubate & Refrigerate

After you add the yogurt, place the contained in which you boiled the milk into a Styrofoam box and let it sit there for 6-8 hours. Then refrigerate the yogurt. The bacteria responsible for the fermentation like warmth for growth, hence the 6-8 hours incubation. 

The first batch is likely to be runny because the cell density of viable cells added from the store-bought yogurt may have been low. Subsequent batches made from a dollop of the previous batch should be thicker and form faster. Commercial yogurt tends to be thicker than homemade yogurt because manufacturers add things like alginate to thicken the yogurt (not necessary).

Mix & Enjoy!

When you go to remove some to eat, mix the watery whey and curds -- all is good for you! :)