- Written by Mattie
Tempeh is an Indonesian protein staple consisting of mashed soybeans fermented with a fungus called Rhizopus olligosporus. I purchased tempeh starter that includes this fungus from Top Cultures. This fungus thrives in a warm humid temperature combined with the nutrient rich soybeans and in about 24 hous grows a complex network of white mycelia that binds the soybeans into a dense mushroomy cake. This fermentation process looks simple on the surface but like most fermentation, it's what's going on behind the scenes that matters. Fermentation creates complex flavor compounds and partially breaks down the soybeans, which makes their nutrients more bioavailable and digestible. As the case with sauerkraut, natural probiotics are also produced that populate your lower intestines with beneficial microflora.
Tempeh has a rich, nutty mushroom flavor. I've found that it really shines when you prepare it the following way:
- Cut it into ½ inch cubes and add it to a small sauce pan.
- Cover the tempeh cubes with water and add salt and spices according to what else you're cooking. Or just add a vegetable bouillon cube.
- Simmer for about 15 minutes then drain.
- Add these flavorful tempeh cubes to whatever you happen to be making: pizza, stir frys, pasta, salads, etc.
3 cups (535 g) whole, dry soybeans
4 cups (946 ml) water
1 ½ teaspoons (7 ml) vinegar
2 teaspoons (7 g) tempeh starter
Hydrate the Soybeans
I used black soybeans for this recipe but you can use white soybeans too. You should theoretically be able to use almost any legume for making tempeh. Place the soybeans and water in a large saucepan. Cover and place over medium heat until the mixture reaches a rolling boil. Remove from heat and drain. Alternatively, soak the soybeans overnight then drain the following day.
Hull the Soybeans
Place the soybeans in a food processor and pulse no more than twice. Rub the soybeans to remove their skins. This is known as dehulling and is the most labor intensive part about making tempeh with hulled legumes. Dehulling allows the Rhizopus olligosporus to get into the nutrient-rich endosperm of the legume and ferment efficiently. Discard the skins.
Cook the Soybeans
Boil the soybeans until just soft, about 45 minutes then drain once more.
Dry the Soybeans
Line two baking sheets with paper towels, spread the soybeans over them and allow to dry.
Add the Tempeh Starter
Transfer the beans to a large mixing bowl. After you've verified that the soybeans are cooler than skin temperature, add the vinegar followed by the tempeh starter. Toss the mixture like a salad until the vinegar and tempeh starter are evenly distributed.
Pack the Soybeans Into the Tempeh Mold
Prepare a 1 gallon freezer bag by placing it over a piece of cardboard and poking an 1/8 inch slit into it with a paring knife every ½ to ¾ inches. This is now your dedicated tempeh bag and it can be reused several times. Fill the bag with the soybeans about half way and seal securely. Place the bag on the counter horizontally and pack it down to about ¾ inch thick, making sure the soybeans are evenly distributed inside the bag.
Ferment the Soybeans
In order to initiate fermentation we need to bring the mixture up to 83F (28C) to 86F (30C) for 22 to 28 hours. After about 16 hours, the fermentation will generate it's own heat which may improperly increase the incubation temperature. It's important to take a temperature reading at this time and reduce temperature back to the original level if necessary.
There are multiple ways to bring tempeh to this sustained temperature but unfortunately there are no commercially available tempeh fermenters available on the market as of this writing. Dehydrators have a fan which is not suitable because it will dry out the tempeh and inhibit fermentation. This means you'll have to be creative but there's good news; making a tempeh fermenter is really simple. Probably the easiest way to ferment tempeh in a home kitchen is to do the following:
Purchase a large cooler and place the tempeh inside on a small cooling rack. Insert a corded low watt lightbulb into the cooler and turn it on, making sure that it doesn't touch the tempeh. Prop the lid of the cooler open with a rolled up towel and take a temperature reading with a thermometer every half hour for the next couple hours. Adjust the rolled up towel to prop open the lid of the cooler accordingly so the desired internal temperature of the cooler is reached. Once you reach 83F (28C) to 86F (30C) let the tempeh ferment about 16 hours before checking again.
In 22 to 28 hours you should start to see black spots begin to appear. At this point the tempeh will have a mushroom aroma and will be bound into a cake via millions of tiny mycelia.
Stop Fermentation and Store
Remove the tempeh from the dehydrator. Tempeh can now be cooked and eaten, refrigerated or frozen. When refrigerating or freezing it's important to initially store the tempeh in flat sheets because their internal heat production will allow them to continue fermenting if stacked. Store tempeh in the refrigerator tor up to 1 week or in the freezer for up to 2 months. Makes about 2 ¼ pounds (1 kg) of tempeh.
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