Semi-recently I started making tempeh. If you're not familiar, tempeh is a soy-based vegan food that sometimes gets used as a meat replacement, but even carnivores can enjoy it. Unlike tofu, it's delicious (SHOTS FIRED) because the soybeans are bound together by a mushroom-like culture that gives it a complex nutty taste. I don't really have any evidence of this, but I think it's probably easier to digest, too, because the culture partially digests the soybeans as the tempeh matures.
But so anyway, tempeh is delicious enough that I make it myself on a pretty regular basis, even though I'm not a vegetarian. Homemade tempeh is substantially tastier than store-bought. (Seriously-- I can't think of anything else with such an immense difference in flavor between homemade and store-bought.) I tend to find that it browns more easily, too, which is important if you want to make phony sausage out of it.
Tempeh is pretty easy to make at home, once you have the necessary setup. It's a little time-consuming, but more-or-less foolproof. And it's also pretty dang cheap-- I use a half a pound of dried organic soybeans per batch, which costs about 85 cents and lasts me a week.
Tempeh is pretty versatile. You can slice it into strips and fry them in butter. You can break strips into crumbles, saute them until brown, and then pour a little soy sauce right in the pan. You can also marinade broad slices in chimmichurri, or soy sauce, or basically whatever, and then bake or fry until golden. I like to occasionally feed strips of tempeh into my food processor with the shredding attachment, which gives it the texture of ground meat. Then I cook it in a cast iron skillet with lots of fat and smoked paprika and cumin and cayenne pepper (and maybe a little vinegar) for a pretty good chorizo approximation which is excellent with eggs.
In Atlanta, Ria's Bluebird has a pretty solid country-fried tempeh dish served over a split biscuit with kale, grilled tomatoes, and white gravy. And I guess people also like tempeh reubens.
Barring that, if you go to all the trouble to make tempeh and then realize you hate it, I'll come to your house and eat it.
THINGS YOU'LL NEED:
THE GIST OF THE PROCEDURE:
Don't be! You can tell pretty easily when your tempeh was a success and when it was a failure. Recently I screwed up a batch pretty bad by insufficiently drying off the beans before adding the starter culture. It was abundantly obvious that I had screwed up because an awful rotting garbagey smell emerged from my incubator. And when I looked at the beans, there were no white patches of fuzz. Instead, the beans had turned this grody puke brown color. Needless to say, that batch went right in the trash, and I learned my lesson about drying off beans.
The goal of all fermentation is to create an environment that promotes the growth of cultures you like while keeping unfriendly cultures at bay. Tempeh culture (whose Latin name is Rhizopus oligosporus) comes from Indonesia, which has an ambient temperature of (surprise) around 85 degrees F. By holding the culture at this temperature, you're creating an environment where it can thrive and outcompete any other nasty microbes. Unless your kitchen is 85 degrees (which, in Georgia in the summer, it might very well be!), you'll need an incubator to keep the tempeh at the right temperature. But, unlike the cultures involved in making brine pickles, tempeh cultures are aerobic-- they need oxygen to grow. So you can't just pop your prototempeh in a sous vide cooker or a Crock Pot and call it a day.
The cheapest and simplest way to make an incubator is to get a styrofoam cooler, a non-LED lightbulb, and a thermometer. (The lightbulb has to emit sufficient heat. I got a garage door lightbulb from Home Depot that works great.) You'll want to rig up the cooler so that the lightbulb is plugged in and shining down from the top of the cooler. Then, you can periodically check the temperature and turn the lightbulb on and off as necessary.
But, if you think a robot could do a better job of checking the temperature and turning a lightbulb on and off, you're right! I rigged up my incubator with an Arduino and a temperature sensor. You can read the source of my Arduino program here. (A schematic diagram will come shortly.) This makes it pretty dang easy to incubate-- I just check the tempeh once or twice a day for the formation of the white fuzz.
It's hard to tell whether your tempeh will be a success until 8-12 hours in.
At that point, happy tempeh cultures will be going to town on the soybeans, which means that the tempeh should be generating a surprising amount of spontaneous heat.
(Note that this means you may even need to ventilate the incubator a bit-- if the tempeh generates too much heat, it can inadvertently make itself too hot and die.)
I usually set my incubator to 85 degrees, but around the 12 hour mark, the heat from the tempeh keeps it at around 87 degrees without any help from the lightbulb.
I now prefer to keep it at 89 degrees.
Additionally, I try to time it so that I'll be able to ventilate the incubator at the 12 hour mark.
I have made several bad batches in a row, and it appears that the problem was that the culture produced so much excess heat that it killed itself!
After the heat generation kicks in, the next big sign that your tempeh is on the right track is the formation of the mycelium. The mycelium is the white fuzzy layer that binds the soybeans into the finished cake of tempeh. The mycelium will start forming somewhere in the middle of the fermentation process. Initially, it will be a little bit clumpy or patchy, which is okay in this stage.
You will know when your tempeh is ready to eat when the mycelium has fully covered the soybeans. In the very final stages of fermentation, you should be looking for a thick, even coating of mycelium. The outside of my tempeh usually feels a little rubbery. You should also be looking for a solid, well-bound cake of tempeh. Nothing should crumble or buckle when you pick it up. It should smell pretty good, too-- a warm, earthy, mushroomy sort of smell, if maybe gently funky in the way fermented things usually are. A couple of black spots near the airholes are fine and shouldn't be a cause for concern. It's just the tempeh beginning to sporulate, which means it's definitely ripe. At this point, you can take the tempeh out of the incubator and pop it into the fridge or freezer (or cook some up right on the spot!).
If there's a ton of condensation on the ziploc bags, it could mean that there was too much moisture on the surface of your soybeans. It's really really important to get all the moisture out!
If your tempeh never starts producing substantial spontaneous heat, the tempeh culture probably didn't take, for whatever reason.
If the mycelium don't form, or if they're present but sort of sad and weak-looking after 24 hours, it's probably going to fail. (This also probably means that it never started producing lots of heat.) Another sign that the mycelium didn't form is that the cake will be loose and sloppy-looking. Good tempeh is a single solid mass. There are lots of reasons why the culture could fail to thrive-- insufficiently hulled beans, too much moisture, not enough air, too high or low temperature... You need to pamper your culture.
If there's a nasty garbage smell at any point, throw it away! Tempeh should smell good. Really ripe (or overripe) tempeh has a certain ammonia-like smell to it, but it shouldn't be overpowering. Trust your nose.
In any case, if your tempeh has failed to mature, try and figure out what went wrong and try again! Notetaking is probably useful here, although I'm not really conscientious enough to keep this up.