The easiest way to make our tempeh is to start with dry roasted, non GMO or organic soy bean halves (unsalted). This saves you all the work involved in de-hulling regular soy beans.
Pour 22 oz. of soybean halves into boiling water, remove from heat and let them sit for 8 - 24 hrs. The beans will expand to twice the size - so use enough water.
The incubation time for the tempeh is 22 hrs. So count back about 23 hrs. from when you want to take it out of the incubator and make the substrate: the soybeans, a small amount of pearled barley and the tempeh culture. This culture is also called Powdered Tempeh Starter (see our Notes).
After pre-soaking the soy bean halves, drain and refill with clean water, about an inch higher than the beans and bring to a boil. Simmer for 35 min - after the first 5 min. add the pearled barley ( 4 oz).
Then drain and put in large bowl.
Use a hair dryer (set on "High") while you stir the mixture of soy beans and barley until they are at room temperature and dry (about 2 min). The tempeh culture does not like extra moisture - so do take the necessary time.
Then add 7 g of the culture and mix it in well. (7g is a about a well rounded teaspoon)
Keep the rest of the culture refrigerated and when it gets older, you might want to use a little bit more.
Place the substrate into the pan and spread it as evenly as possible. At the end pat it down flat.
The incubator should be operating (air pump and heater on) and the water temperature should be 87˚F . Close the lid (it does not need to be locked) and notate that in 22 hrs it will be finished. After about twelve hours the tempeh will start making its own heat and at the end of the 22 hrs the water temperature will be somewhat higher (this batch reached 91˚F). This temperature rise is normal and the amount of water present will prevent it from overheating.
22 hrs later:
After 22 hrs the tempeh is finished and the mycelium should be thick and white. If it goes longer or the temperature was higher, the mycelium will sporulate and this will show up as dark areas - which is fine if you don't mind it.
Take out the tray, cover it with the lid and put it into an oven at 175˚F for 25 min. This will stop the culture from continuing to grow. Once it cools it is ready to cut into the desired shape and can stay in the refrigerator for 5 days or be frozen. We often pre-marinate it before freezing.
The above recipe is good for t-burgers, t-dogs and cubes. For paninis we use only 18 oz of the soy bean halves and 3 oz of pearled barley (and 4 g of our own culture).