Tempeh - how to make your own

Tempeh is a protein rich food which consists of fermented soy beans. It is originally from Indonesia but it has gained popularity throughout the whole world. It can be used as a meat substitute and has a neutral taste which makes it possible to flavor it with your own favorite spice. This food can be done in 24 hours!

Today I will write about how to make your own tempeh and about the chemical procedures that involves this food process. If you are not interested about the chemistry behind the process, simply skip the following text and jump to the heading named "Make your own tempeh" below.

Chemical Process
The fermentation of the soy beans is made by adding a fungus named Rhizopus oligosporus which will form a white mycelium (similar look like the one on Brie cheese). This mycelium will hold the beans together and form a cake. The chemical process when fermenting the beans is that the Protein Efficiency Ratio (PER) will increase, this means the protein in the beans will be more bioavailable, because the fermentation will partially break down the protein. Also the B-vitamin content will increase and there will be an degradation of inhibiting enzymes, such as trypsininhibitors.

Rhizopus oligosporus
This fungus can be hard to buy, depending on where in the world you live. But google it and you will find online shops that sells it. This fungus grow at 30-42 degree celsius and grows really fast. R. oligosporus has a strong lipolytic activity which will break down some of the fat in the beans to free fatty acids, this will affect the taste. It also has a proteolytic activity, which will break down protein into amino acids, this will also increase the taste of the tempeh when you cook it. If the fermentation is not stopped the proteolytic activity will start to release ammonia which will raise the pH and the fermentation will stop, because the fungus does not like higher pH. The fermentation will also break down the beans matrix, which will make the beans cling together and form the "cake".

Make your own tempeh
You need:
500 g of soy beans
Rhizopus oligosporus (google it and you will find it), Look at the instruction for amount on specific fungus, this comes with the product
Vinegar
Flat Boxes with lids that has air holes

First, the beans must soak for 8 hours in water.
Then you have to rinse them, this is kind of tricky and not all shells have to be removed, but most part of them should be rinsed. You can do this by taking many beans in your hand and rub them.

Put the beans in a cooking pot, fill up with water (approximately 5 cm above the beans) and add two table spoons of vinegar.

Boil for 30 minutes.

Put the beans in a colander and remove the water.

Put the beans on a clean towel and spread them gently and try to dry them with another clean towel, but do it gentle.

Let the beans cool down to approximately 37 degree celsius (you can feel this with your finger).

Add the Rhizopus oligosporus (correct amount should be given on the instruction of the fungus) and mix the beans well so that the fungus is spread evenly.

Put the beans in the flat boxes. Press down as much as possible.


Put the boxes in a warm place (about 30 degree celsius) for 24 hours. This can be tricky if you live in a cold place. But you could use your oven, just put the lamp in the oven on, and no heat. This COULD be enough for most ovens. But no guarantees are given.

You should be able to see the white mycelium after about 12 hours. And after 24-26 hours it is ready.

Either eat directly or freeze it down. The tempeh can last in refrigerator for a couple of days, but I recommend freezing if you are not going to cook it directly.

I prefer to fry it gently in oil and adding chinese soy sauce. Enjoy!