How to make tempeh?
Step 1: IngredientsYou need about 500g whole soya beans, a few tablespoons of vinegar and a bit of tempeh starter to make 1 kg of tempeh. Tempeh starter contains either spores of Rhizopus oligosporus or Rhyzopus oryzae, or a mixture of both. You can buy tempeh starter from TopCultures, they ship worldwide.
Step 2: Soaking and dehulling soya beansWhole soybeans can be dehulled by soaking the beans for 8 - 14 hours in water and then removing the hulls by hand. In doing so, the beans are split into two halves and the seed coats can be discarded.
Step 3: Cooking the dehulled beansPlace the soybeans in a cooking pot and add just enough to water to cover the beans. Add the of vinegar, bring to boiling point and simmer for 20 minutes. Drain and remove the cooked beans onto towels to drain off the excess water and to cool the beans, which are now swollen and soft. It's important that the beans become very dry, otherwise undesirable bacteria can grow and create off-flavours.
Step 4: Inoculating the dehulled beansPut the cool and dry beans in a clean container and sprinkle them with 1 teaspoon of tempeh starter (can be ordered at tempeh.com) and mix thoroughly. The exact amount of tempeh starter required is given on the package of tempeh starter.
Step 5: Incubating the beansTake 2 plastic bags about 18x28 cm and perforate them with holes at a distance of about 1 cm by a thick but sharp needle.
Divide the soya beans in the two bags and seal them. Press them flat, making sure that the total thickness of the beans is not more than 3 cm.
Place the packed beans in an incubator at 30°C or at a warm place for about 24-48 hours or until the container is filled completely with white mycelium and the entire contents can be lifted out as a whole piece. A simple incubator can be made with putting a light bulb in an old fridge. Depending on the room temperature bulbs with different wattage (15W, 25W, ..) can be used, but remember that the tempeh will also produce some heat on its own.
The fresh tempeh will feel warm and will have a pleasant mushroom flavour. The finished tempeh can be store in refrigerator for 7 days or a few months in the freezer.