Yogurt

Making Yogurt - Jan Garvin
Lois
Near Eastern Yogurt - Robert Henrickson
Joann's Mom's Yogurt
Kat Sherman-Hoehn and Yogurt-Making
             Jan Garvin
             Maureen King
             Lois
             Philip Johnson
             Marian Van Til

Making Yogurt - Jan Garvin
Yogurt's one of those incredibly easy things to make that will make you wonder why you ever paid $.75 for a four ounce tub...
The official directions will tell you to scald a quart of milk, cool it to tepid (about 103 degrees F.), then inoculate it (stir in) with a couple of tablespoons of commercial organic yogurt. Incubate it at about 105 degrees for anywhere from 8 to 24 hours, and you're done.
Being of lazy disposition, and since I usually start with pasteurized milk, I don't bother with scalding the milk, I just nuke it till it's slightly warm to touch, stir it, stir in the starter, and incubate it. You can purchase yogurt makers from any decent health food store, but you probably don't need one. If you have a crock pot, you can probably wrap the quart of inoculated milk in a soft towel and let it sit overnight in the crock pot, set on low with the lid off. When I was much younger, and still had a stove with a pilot light, I'd wrap the covered glass jar in the towel and let it sit overnight over the pilot on my stove. I've also been known, in the really hot summer, to just inoculate the milk, put the lid on the jar and put it out in the hot air, the way you would make sun tea. If you try to culture it in the outdoor air, I wouldn't put it directly in the sun, because it will overheat and die. It's a living organism, and like all such, it has temperature ranges that it can't survive beyond.
You will probably find that it is considerably more tart than the grocery store variety, and it will probably be less thick, because most grocery store varieties are thickened with carragenen. You can achieve much the same texture by adding a tablespoon or two of dried milk solids to the warmed milk and stirring it in before you stir in the inoculant.
Once you've got your yogurt, you add fruit, other flavorings and sugar or honey to taste. No, it won't taste like what you buy in most stores, but it will be the genuine article.
If you shop in Whole Foods or Wild Oats, you may find powdered cultures that you can add to the milk instead of using an inoculant from a commercial yogurt, and you will certainly find commercial yogurts made from a number of different types of bacteria, each of which will give a different flavor from the others, and which will have slightly different health effects in your body. You will probably also find commercial products made from milk other than cow's milk, and obviously, different types of milk produce different types of yogurt; again, with different effects on our body. Many people who can't consume cow's milk, or anything derived from it can consume goats milk quite successfully. I don't know the whole reason for this, but I do know that part of it is because the goat's milk, while containing similar amounts of fat to cow's milk, distributes the fat through the milk in smaller molecules. To give the merest nod to the Canon, at one point Jack and Stephen are preparing to drink a cup of coffee, but the only milk available is goat's milk, which they reject. I've often wondered why. I don't find the flavor all that different. I have no idea what sheep's milk, camel's milk, or mare's milk might taste like, but those are all milks that humans have drunk and from which they have produced cheeses and yogurts.

Lois
In the dark ages, when I tried making yogurt for my kids, I remember putting little "pots" of it in a roasting pan on the counter, putting the top on the roasting pan, and leaving it overnight. In the morning, it was set.
I never became much of a yogurt maker. Too much trouble for too little eaten product.
My grandmother, apparently, made cheese this way. She "set" milk overnight, and then put the gelled stuff in a cloth, put that in a strainer, and leave it a couple of days in the pantry, while the liquid drained out and it solidified. Then she would wring out the remaining liquid with the cloth, and end up with a ball of something like cream cheese. They ate some of that, and then she pressed stored the rest in some unremembered way which produced what her children called "stinky cheese". They loved it and remained nostalgic about it the rest of their lives. I've tried it up to the cream cheese stage, and it's pretty good. Never went any further. She had a cow for her milk, so don't think I could reproduce her product with milk from the supermarket.

Near Eastern Yogurt - Robert Henrickson
'Yogurt cheese' is a staple of Near Eastern village life. In Iran, its name translates as 'bag yogurt'. This soft cheese is dried for winter use. It can indeed be 'stinky cheese'. One of the soups regularly served at lunch in Turkey (in my years at Gordion) has this as an ingredient. People have definite opinions about it -- love it or hate it. It does mean that those days I can get a second serving!
In my 20 years at Gordion, it has been interesting seeing the village dairy culture change. For the first 10-12 years I was there, the long-traditional sheep-based dairy products were standard. There were few cows in the village. In the late 1990s, there was an abrupt shift to cows -- the local market town (20 km away) started sending trucks to pick up fresh milk. In the course of a few years, sheep flocks almost disappeared, replaced by cows. As the sun set, we'd see the herds of cows come home, rather than flocks sheep; the cows were smart enough that when the herd reached the edge of the village, they would separate and go to their individual owners' compounds.
Then several years ago, there were two years of drought. By the third year, the number of cows had shrunk by perhaps 2/3, and flocks of sheep were back. This time, the sheep flocks had a few more goats than before (someone has to lead the sheep), though the primary lead animal is usually a donkey and the shepherd.
Village yogurt has no equal. The project goes through a 4-5 qt pot every day. Since the butterfat remains, it sets up rather firmly -- a Near Eastern villager would regard yogurt made with other than whole milk with horror. Sheep milk yogurt has a better favor than cow -- perhaps more butterfat? A colleague who has worked in the Near East for 40 years says that part of the traditional taste of village yogurt came from the smoke of dungcake fires -- dungcakes are a traditional primary fuel, though now used less and less. Waterbuffalo milk provides an even richer yogurt (northwestern Iran). After working for more than 30 years in the Near Eastern villages, the only thing that tastes remotely correct in the US is whole milk organic yogurt.

Joann's Mom's Yogurt
My mom used to make yogurt a lot when I was growing up. To make about a gallon of yogurt, she'd use a gallon of milk, add some powdered milk (dry), the starter, and gelatin. I don't think there was anything else. I don't use the gelatin, but if I can I'll add the powdered milk. I haven't done it in a while but she used to use the Sanalac brand, and added a whole packet. I don't use gelatin.

Kat Sherman-Hoehn and Yogurt-Making
After all the list discussion, I decided to try making yogurt myself. I briefly boiled some half and half, added a cup of (non-fat) plain Greek yogurt as starter, and put under the oven light to incubate. It... isn't really yogurt. It's a really GOOD ricotta subsitute, and mixed half and half with sour cream it made a killer mushroom stroganoff, but it's not yogurt.
List yogurt makers, any suggestions? Where did I go wrong? Or is it just the nature of the beast that sometimes the yogurt sets and sometimes... you end up getting out your lasagna recipes?

Jan Garvin
Pretty much, it's the nature of the beast. I've never made it from half and half, but my guess is that half and half makes a stiffer product than other milk products, and that you incubated it long enough to separate the curds from the whey. The "sour cream" that we typically use in the US is a cultured product, but I don't know what the specific bacterial culture is. My guess is that it's related to the yogurt cultures, so you may indeed have created a product very similar to commercial sour creams.
Some people make a "yoghurt cheese" by getting the yoghurt to the stage you did, then wrapping it in several layers of cheesecloth and letting it drip overnight into a clean pan. The curds remaining are the product they eat as cheese, and the whey is very wholesome to just drink. I've never done it, just read about it.
As for what you did wrong, probably nothing, although there are things you can try, to see if you can get a product closer to what you expect.
Try the following ideas, one at a time, and see what happens.
Use a less rich milk.
Incubate a shorter period.
You don't really need that much inoculant. Using it won't hurt anything, but you don't need it.
Don't bother to boil the milk before you inoculate it.
I've been making mine from whole milk, adding two tablespoons of dry milk solids (not bothering to boil the milk and cool it, although I did once, just to test the technique, and you do get a firmer product by boiling the milk, just like someone else said you would) and incubating it overnight. The product I've gotten is less stiff than the commercial product I started with. Ted's lactose intolerant, but he seems to be doing fine with the shorter incubation times.
I don't know whether I mentioned it or not, but once you've gotten a culture going, you don't need to purchase a new batch of commercial yoghurt each time you want to start a new batch, provided you refresh the culture often enough that it doesn't spoil between batches. I usually use a quart jar twice (using the last of the first batch to inoculate the second) before I sterilize and use a fresh jar. It's very much like keeping a sourdough culture going.
BTW, I mentioned that I had managed to pick up a wild yeast in that first batch of yogurt I made, and that I was going to culture it to see what kind of flavor it produced (different strains of yeast, both domesticated and wild, give different flavors to the breads made with them). I did that, and the flavor was indistinguishable from the commercial product I normally use for bread making. Worked fine for leavening both bread and waffles, but just tasted like grocery store yeast. Sort of good news, sort of disappointing (I like the sour San Francisco sour dough.)

Maureen King
I wonder if the problem is the amount of yogurt used as starter. I usually use a heaping tablespoon to a half-gallon of milk, well whisked in, and it sets up nicely.

Lois
Think I wouldn't use that super-pasteurized stuff, it's unpredictable.
Half and half, and whipping cream that is overprocessed, hyper-pasteurized like that never works for me. The stuff "leaks", water seeps out of the lovely stuff. So it might not set the way it should.
Also, the oven light may have given too much heat.
Yogurt can set at room temperature. I've sometimes "made" it inadvertently by leaving something out overnight.

Philip Johnson
Rather than putting it in the oven, wait until it cools to the right temperature and then put it into a (warmed, preferably wide-mouthed) thermos flask.

Marian Van Til
I do make my own yogurt. And it's VERY good, if I may say so myself. And it's easy.
I did buy a new yogurt maker, which works fine; it's the kind with the individual glass jars and a timer that goes up to 15-hours, to which I add another 9. (EuroCuisine brand). But I could have saved myself the money. The process works just as well, and is actually slightly easier to let it do its thing in the oven.
You'll need a sauce pan and cover (it's nice, but not essential to have a glass-covered pan that you can see through), thermometer, oven with a light, a quart of milk or 1/2 and 1/2; some plain yogurt as starter. (One of those little individual containers of plain Dannon works very well. Don't use low-fat yogurt as the starter. Or any starter yogurt that has added milk solids, starches, etc. to the milk in it; and of course, no flavorings.)
Start by putting a quart (or two, or half gallon carton) of whole milk or 1/2 and 1/2 in a sauce pan. (If you're doing as much as a half gallon at a time, use two individual containers of starter; about 3/4-1 cup of it. Half-and-half makes creamier yogurt and is an excellent source of protein and fat, the more so if one doesn't eat a lot of meat.
Heat it to just about boiling. (Some sources say to actually let it boil; others don't; I find it works just as well not to, and is less messy. Let it cool in the pan for a while to about 105-110 degrees. (If it cools down slightly more, I've found that's not a big deal; but don't let it get too cold before you put it under its heat source to ferment. I use a meat thermometer to check it.
In the meantime I turn my oven light on, which I've found keeps the yogurt perfectly at 110 degrees when the pan (covered) is placed in the oven. I leave it there for 24 hours in order to enable all or virtually the lactose to be used up in the fermentation process. But you'll get good yogurt after six or eight hours. (I know people who use a warming plate instead of an oven; a crockpot will work too, as long as it has a low temperature of not more than 110 F.) Don't stir it before it's done.
My 24-hour yogurt is very thick, creamy and nicely tart. It's marvelous with fruit on it/in it; or would be good with a dollop of jam, honey, or is very good plain, if you like it tart.
I've used as much as a cup of starter yogurt for a quart of 1/2 and 1/2, but it's true: you don't need that much. Try 1/2 cup, or even a 1/4. I've not tried as little as Maureen does, but if it works for her, that's a possibility too.
But I'm thinking that the problem is with your incubation temperature. I suspect your yogurt doesn't stay hot enough to ferment properly. Or, depending on what you're doing, it could be too hot.
That, and the shorter the time incubated, the runnier the yogurt. Don't be afraid to leave it a full 24 hours. That will also get rid of all the lactose in the 1/2 and 1/2. I get wonderful, thick -- really thick! -- yogurt using 1/2 and 1/2, Fage plain Greek yogurt as starter, and incubated in my (electric) oven with the oven light on (warmed up for a while ahead of time, either with just the light, or turning the oven on for about three minutes. My oven light keeps the oven temp. at about 110 F.