Tempeh is fascinating food. You take soybeans that do not have any taste. Adding a little tempeh starter and a lot of time makes it into something with a lot of taste. I know tempeh can be intimidating. Mediocre supermarket tempeh or tempeh not prepared well can be bitter or boring. But homemade tempeh cooked right is absolutely delicious. I have made tempeh from chickpeas too, but so far soybeans gave me the best results.
Soaking the beans
The first step is to soak soybeans overnight. Put them in a lot of water, as they soak up quite some water. For the best result remove the skins from part of the soybeans. That is easily done by pinching a bean between two fingers. I only remove the skin of a small part of the beans, but it helps the mold grow better.
Cooking the beans
Next up is cooking the beans. They need to be just done. Not totally soft. Somewhere between 1 1/2 to 2 hours will do. Taste them, and if you can easily eat them, they are fine. Drain the beans and let them cool down to below 40℃ (104℉) Mix the beans with tempeh starter. You need around 1 teaspoon of starter for 500 grams of beans. Tempeh starters can be purchased in specialty stores and online. I do get mine from Naturitas.
Packing the beans
Originally these get packed into big leaves. But plastic zipper bags work well. I use the 0.4L Ikea bags and they do the job. Put beans in the bags and make a few holes in every bag to let the air out (and some air in during the process) I do around 20 holes per bag using a wooden skewer.
Let it grow
Next the bags need to be kept in a warm place. The best temperature is around 32℃ (90℉) I have an oven that can be put at this low temperature. With some ovens keeping the light on already brings it to the right temperatures. People have also made special constructions with plastic containers and aquarium heaters. But if your oven can do it, no need…