I'm exhuming this thread, which is the most recent I could find of the ones that discuss homemade yogurt. Someone else did the same for the sourdough thread, which I really appreciated. I've always been into home cooking, but since I FIREd, I've been making even more things myself at home. I like the idea of going farther and farther back on the "production line" -- buying flour and yeast instead of bread, dry beans instead of canned, etc. It's a fun challenge for me, and in most cases, it's tastier and cheaper!
I wanted to add this for those who don't consume dairy, for whatever reason.
I've been vegan/plant-based for 4 years, but before that I ate yogurt at every single lunch, day after day, for at least a couple of decades. I haven't really missed it, but sometimes it would be nice to have it. Sure, there's plant-based yogurt out there, but just like most dairy yogurts, it's loaded with sugar, preservatives, etc. And it's expensive! So today I made my own soy yogurt, or at least I think I did -- it's fermenting as we speak. I did buy a $26 yogurt maker for convenience:
https://www.amazon.com/Euro-Cuisine-YM80-Yogurt-Maker/dp/B000EX16RY/I was given some yogurt starter packets for Christmas, but I think after those are gone, I'll get some probiotics instead. I don't like the idea of starting with a commercial yogurt because of all the other junk in it, but I'd do that in a pinch.
Also, since I was heating up soy milk anyway, I thought I'd try my hand at homemade tofu! And it worked! I guess that's the vegan equivalent of the cheese-making some people here have suggested here. One benefit of doing all this with soy is that it's pretty cheap. I bought 7 pounds of non-GMO soy beans for $17 on Amazon, and although I'm kicking myself for not measuring before using any of them, I've read that that's equivalent to about 34 cups of beans, so using those to make soy milk and then yogurt and tofu is pretty cheap!