Adventures in Yogurt-Making

I like yogurt. When I was a kid, I could not get enough. When I ran out of yogurt that I had picked out, I would sometimes ask my mom if I could have one of hers.

Those yogurt cups are not cheap, though. It adds up. So when I read somewhere about people making their own yogurt, I did some reading and decided to give it a try.

First, I tried using the flax milk I already had on hand (I'm a vegan) using a store-bough cup with active cultures as a starter. It tasted good, but did not thicken much at all.

So I decided to go full-steam from-scratch. I ordered a bottle of probiotic capsules. The bottle I bought was 150 billion, but most of the recipes I found called for a minimum of 50 billion. Again, I tried flax milk, but it didn't work at all. So I finally bought some soy milk, which I'd already known from my reading curdles better than any other vegan milk.

I started out with heating the milk to almost boiling then letting it cool down to very warm, but not scalding. I opened a probiotic capsule and whisked it in, then left it overnight in my oven with the oven light on. (Using the oven light only works if you have an incandescent bulb.) This didn't work out very well, either, and eventually, I surmised that stirring the probiotic into the metal pot and using a metal whisk was - as I had already read - detrimental. I had figured it would be fine for stirring before pouring the mixture into glass jars, but apparently this is enough to sour the mix.

Now I have a system that works for me and I'd like to share it.

1. If you have soy milk in shelf-stable cartons and you don't keep them in the fridge, no need to heat the milk. One carton is four cups. Pour it directly into a glass container, such as a large Pyrex measuring cup.
2. Using a wooden spoon or plastic/rubber spatula, stir the contents of one probiotic capsule into the milk, until you no longer see any lumps of probiotic powder.
3. Place the milk in your oven and turn on the oven light. If you don't have an oven with an incandescent bulb, you'll need to find another stable warm area somewhere between 90 and 100 degrees. Higher than 110 degrees will kill the probiotics. Cooler than 90 and nothing will happen.
4. Leave uncovered and undisturbed in the oven for 8 to 12 hours. The exact amount of time depends on your taste. The longer it cultures, the tangier it will be. I've read some people leave it up to 16 hours. I suspect beyond that might not be a good idea. 
5. When it's minimally done, you should see a gelatin-like surface broken by small cracks, and a watery bottom. Transfer the entire mixture to a blender, place a cloth over the cover, and holding the cover firmly, blend for several seconds. The cloth is to ensure whatever pushes against the cover doesn't leak all over your blender and counter. 
6. Rinse out the glass container and pour the mixture back into it. Cover and leave in your fridge overnight. 
7. When that's done, you should see the solid yogurt on top and a small layer of whey at the bottom. Scoop the yogurt out into your favorite small storage containers. Use within a few days at most. You can save a little in a separate container to use to start a new batch, which I have not tried yet but I've read should work just fine.

And now... photos.

Getting started: glass container, soy milk and probiotics.

One capsule per four cups of soy milk.

Open capsule and dump into milk. No metal!

Place in oven with oven light on overnight.

Do not disturb.

When done, it should look like this on top. Leaving it longer makes it look even more cratered.

It should look something like this from the side.

Blended and creamy, ready for fridge.

After cooling in the fridge, you should see this.

Scoop into containers. Save a little for your next batch. You can discard the whey or use it in a smoothie or to make oatmeal.