Everyone is always surprised at how easy it is to make yogurt. When I first learned how to make it, I remember thinking, "If it's really that easy, then why would people bother buying it? Obviously there's more to it than 2 ingredients, and 5 steps, right?" But honestly, it's really is that simple, I haven't bought it since I've started making it, and neither will you.
I love fermentation, and I love talking about it--it's like food science and it makes me giddy (wow has my life changed.) This post,Fermentation 101, discusses fermentation in more detail, but basically, all you need to know for now is... yogurt is just fermented milk. Shocker! With the help of beneficial bacteria from the starter-yogurt, the sugar in the milk, lactose, is fermented into lactic acid which coagulates (I hate that word) the milk. This fermentation process creates a probiotic-rich yogurt which helps to maintain healthy gut flora. That's the very basics to behind the scenes of fermenting yogurt.
For fermentation to take place, the good bacteria need a warm environment to thrive, about 100°. As I mentioned in Step 5 below, putting your yogurt in the oven with ONLY the light on, provides a perfect temperature for the milk to ferment.
When your yogurt has finished fermenting, which takes about 24 hours, it should have a custard-like texture, a thin layer of yellow-ish liquid (whey) on top, and contain a mild, tangy taste. Your yogurt may not be as thick as some store-bought, because store-bought yogurt contains artificial thickeners. But rest assured, this yogurt is quite thick as far as homemade yogurt goes!
In order to turn this yogurt into Greek-style yogurt, simply strain some of the whey out using a cheese-cloth.
If you would like to sweeten or flavour your yogurt, stir in some honey, Grade B maple syrup, homemade jam and/or berries, once it has finished fermenting.
This yogurt also pairs perfectly with homemade granola.Don't forget to set aside 1/2 a cup of your finished yogurt as your starter in your next batch.