Sometime last year, I got on a yogurt kick. Now, for the better part of a year, I've eaten yogurt for breakfast nearly every day. While yogurt is a little challenging (it's tangy and nothing really covers that taste), there is something comforting about it anyway.
At some point, I realized that I was 1) spending a ton of money on yogurt and 2) recycling a whole lot of plastic because of the containers. (Quart containers are a possible solution, but even so you end up with a lot of them. And then there's the problem that you're not sure how much you're getting on any given day. I'm compulsive enough to want to eat about the same amount each morning, but not compulsive enough to measure it.) That was when I decided that it would be a good idea to make my own. Sue and I had done that back in the 70s and 80s but had somehow gotten out of the habit. We had even gotten rid of the Salton yogurt maker we had: we probably thought it wasn't worth moving at some point.
So I bought a new yogurt maker last summer, and ever since, I've been eating yogurt I make myself. There's a lot to like about this. First, I'm not using nearly as much plastic, and second it's cheaper. But that's not the real fun. I think what I like best about it is the sort of "science experiment" aspect of it. In fact, I think this is one of the things that appeals to me about cooking in general: there is a certain alchemy involved in putting a bunch of stuff together, heating it, and watching the magic happen. Bread and yogurt, which involve getting living organisms to do the work, are especially gratifying from this point of view. They also have an element of uncertainty that other cooking doesn't have. I mean, this time the little yogis (as I like to think of the bacteria that change milk into yogurt) might just choose to do something different. They are, after all, alive and therefore a little unpredictable.
That said, my yogurt and bread come out just fine, time after time. That's because, as you might imagine, I've paid attention to what happens and have been careful about the process--so I know what to do. In fact, yogurt making is fairly simple and forgiving. You just have to combine some live yogurt cultures with milk and keep it warm (about 110* F) for a while until it turns into yogurt and has the tang you want. The easiest and most reliable way to do this is with a yogurt maker, but setting a jar in the oven with a pilot light (if you still have such a thing) will work. I've even heard that you can put the warmed milk and culture into a thermos, close it, and leave it overnight--you'll have yogurt in the morning.
Even though it's simple, there are some things that help, so I'll share them. First, pick a commercial yogurt you like and use that as your benchmark. This will be your standard, your measure for success. It makes sense to use this as the starter, because yogurt tastes different and has a different texture depending on the yogis that were involved in making it. For your starter, it's important for the package to say "live yogurt cultures," because that's what you need to get things going. Also, use plain yogurt. Flavors can be added later. I like Stonyfield Farm yogurt, but I've also had success using Fage as a starter. In the old days, we used plain old Dannon and it worked just fine.
I have found that organic milk makes a better product (firmer and creamier) than non-organic. I don't know why. I just know that once the market was out of organic milk, so I bought the other kind (inorganic? surely not) and the yogurt didn't turn out as well: it was a bit runny. Heating the milk to nearly boiling used to be called for to ensure that you had killed off any stray stuff that might attack the yogis or interfere with their operation. Modern processing methods make that less necessary, but it turns out that heating the milk makes the yogurt firmer and creamier, so I recommend doing it. We used to add dry milk to the yogurt (the non-instant kind is best), but we've found that we like the yogurt just as well without it.
So here's my process:
2 quarts of organic 2% milk (though skim, 1%, or whole will work just fine: it's a matter of how much fat you want)
12 oz plain yogurt with active cultures (I use 2 small packages of Stonyfield)
In a large saucepan, heat the milk over medium heat until it reaches 180* F. (I use a digital probe thermometer affixed to the side of the pot for this. Very exact, very reliable.) This will take about 15 minutes. Resist the temptation to use higher heat: you'll just burn the milk on the bottom of the saucepan. Stir occasionally if you want, but it isn't crucial. Larger surface area makes this go faster, so I usually use a dutch oven.
When the milk has reached 180* F (it will be foamy and on the verge of boiling), remove it from the heat and set it in the refrigerator. Allow it to chill to 110* F. (Again, the probe thermometer is helpful here. Mine has an alarm you can set when whatever you're measuring hits a particular temperature.) This will probably take about 45 minutes. It is important that you allow the milk to cool: if it is too hot, you'll kill the starter. If it gets too cool, it will still make perfectly good yogurt; it'll just take longer. And how much longer? Who knows. So being precise here will give you more consistent results, if that's important to you. (It is to me.)
When the milk is cool, skim off and discard any skin that may have formed on the top of the milk. Whisk the 12 oz. of yogurt in a bowl or large measuring cup--I use a 1 quart measure. This smooths out the yogurt and makes it easier to mix. Pour some of the warm milk over the yogurt and whisk it to combine. Then add that back to the pot of milk and whisk thoroughly. (Mixing the starter with some milk first ensures that the starter will blend with the yogurt more thoroughly and more easily.) If you have any worries that you might have burnt the milk a little, just be careful not to scrape the bottom of the pot with the whisk when you stir. (And use lower heat next time.)
Pour the milk and starter into yogurt glasses. I pour it from the pot, which I used as the mixing vessel, back into the 1-quart measuring cup and use that to fill the yogurt glasses. This quantity of milk and starter will make 12 6-oz. glasses of yogurt. Put the glasses in a yogurt maker and follow the manufacturer's directions. I incubate mine for 8 hours, but you might like more or less depending on how tangy you want the yogurt.
When it is done, remove the yogurt from the machine, cap the jars, and refrigerate overnight before eating.
And that's all there is to it! This will make great yogurt that you can use for cooking or eating. If you like it thicker, you can strain this overnight for wonderful Greek-style yogurt or yogurt cheese. You could probably also just put the mixture into a big jar or two and set it in an oven with a pilot light--or even put the oven at 110* F if it will let you do that (only that probably uses more electricity than you want). I know people who've been successful rigging up something with a heating pad. After all, people were making yogurt centuries before electrical appliances were invented.
Once your yogurt is ready, you can eat it as is or garnish it. I like a little fruit in mine--some blueberries, melon, or apple is nice--whatever's in season. If I want something really nifty, I'll take apart a pomegranate and put the seeds (more properly, "arils") into the yogurt. I also put wheat germ or something else with fiber in it. (I have some wonderful granola that Noa's mom in Venezuela made me--delicious!) Lately I've also been using ground flax seed. If you like it sweet, try a drizzle of honey. You could also stir some good jam or jelly into the yogurt if you like.
There is something incredibly gratifying about starting your day with something you made yourself--even if it is simple. It somehow makes me feel a little virtuous, like I had to do a little something to earn my breakfast. Of course, there are all the health benefits of yogurt, and making it yourself means that nothing got in there that you didn't want. But that's not really why I do it. I make yogurt because I'm fascinated--every time--that it worked. I guess I'm just easy to please.