I majored in Microbiology in college. I loved the study of life not quite visible, life that you know is there even though you can’t see it, unless you have the aid of technology or deductive reasoning. My sophomore year, I got a much coveted position in a lab, and after one lo-o-o-o-ong summer of pricking petri dishes I left science entirely and switched my major to Theatre Arts. But, as we have discussed before, life comes full circle. I study bugs again, but now I study them in my kitchen.
If you don’t already make your own yogurt, let me suggest to you that you should. It’s easy, and fun, and good for your health, and saves money, and puts you in touch with life that you can’t see.
Here’s the very simple version:
To make yogurt, you… Heat your milk to very hot. Cool it down to warm. Add some yogurt starter. Keep it warm all day. Put it in the fridge overnight. Done.
To make Greek yogurt, you… Heat your milk to very hot. Cool it down to warm. Add some yogurt starter. Keep it warm all day. Strain it in a cloth bag for an hour. Put it in the fridge overnight. Blend it vigorously with a whisk. Done.
See? It isn’t a recipe, so much as a natural process. You create an environment in which the microbes can do what they do, and then they do it.
Now, step by step.
1. Heat your milk to very hot. (Pasteurize the milk.) Your goal here is to eliminate the competition, by killing any bacteria hanging out in the milk in the first place. Some people don’t do this. But lots of us do. It’s easier; the product is more consistent.
Put your milk in a nice heavy pot and heat on a stove top up to 180-190 degrees. Go slowly at first, and stir, so it doesn’t burn or stick, and don’t go past 195 degrees; that will boil the milk and you’ll get skin on top. If you don’t use a thermometer (and I don’t, ever), watch little bubbles form around the edges first and then in the middle, until there is a thin layer of froth on top. My mother called this scalded milk, it has that Parisian coffee shop steamed-milk smell. Keep it like this for a couple of minutes. If you see big ripples start to form, like there’s a sea monster in the bottom, it’s about to boil, take it off the heat, you’re done.
2. Cool it down to warm. Create optimum conditions for growing the bacteria you like.
Put the whole pan in an ice water bath. I use the sink. Take it out when it is below 130 degrees. This is approximately the point at which you can put your hand on the side of the pan and it doesn’t burn you. (This test won’t work unless you’re stirring the milk, though.) Basically, if the milk is hot enough to hurt your hand, it will also hurt the bacteria.
3. Add your yogurt culture. Don’t skimp on this. You can’t make your yogurt any better than the culture it came from. So use a yogurt you like. If you want Greek yogurt, start with a Greek yogurt culture. Also, not the flavored kind. Plain.
Add 2 Tbsp of live yogurt culture per quart of milk. Stir well.
4. Keep it warm for several hours. The bacteria you just added will be fruitful and multiply. It will eat the lactose (awesome news for those of us who are not so good with lactose) and will create acids. The acids make proteins in the milk precipitate, which just means become solid. And that is what turns milk into yogurt.
You just need to pick a method. There are SO MANY. A “yogurt maker” only does this one thing, but it does it well; I use one as long as I’m near an electrical outlet. I also have used a crock pot, and a warm thermos, and right now this minute I am attempting a Dutch oven. Other people I know have used glass jars in a warm water bath, or in a cooler. The time of incubation depends on temperature and temperature consistency, but also on your taste preferences. For my strong, plain Greek yogurt that I like, I go seven hours at 110 degrees. Longer incubation will give you a thicker yogurt with stronger taste. Shorter incubation time will give you milder and more delicate.
5. Put in the fridge overnight. When you look at your incubating yogurt, even if everything is going right, it may look a little funky. There’s chemistry going on. But when you cool it down, all the action will stop, and you can work on your product.
Put it in the fridge right away when it’s done, don’t transfer it or even stir it until it’s cool.
FOR GREEK YOGURT
6. Strain in a cloth bag for an hour. We used to have a nice commercial muslin bag for this, but it went missing in the move, so Nick made me a new one out of an old sheet. I use it seam-side out to avoid threads, And, little tip, it DOES matter where it hangs. If you hang your yogurt by the garlic braid you’ll have garlic-flavored yogurt. (oops)
Hang the bag up on a hook or a cabinet door and let the whey drip out into a bowl. The longer it hangs, the thicker it gets.
7. Blend vigorously. Don’t do this until it is cold, but once it is cold, go to town on it. Some people use an immersion blender. I just use a lot of energy. The more you whisk it, the creamier it will be.
Do you already make your own yogurt? Any tips to share?