Tempeh is a traditional Indonesian food made from fermented soybeans. You might think of it as a firm Camembert cheese made from soybeans instead of milk.
Tempeh is highly nutritious, high in protein, easy to digest, and tasty. It can be consumed the same way as tofu or meat: marinated, cooked in a variety of ways, and incorporated into many dishes.
Tempeh is prepared with legumes (often soybeans), water, and tempeh starter culture (Rhizopus oligosporus or Rhizopus oryzae). Once the legumes are cooked, the starter culture is added, and the beans are incubated. During fermentation, the culture develops white filaments (a kind of mycelium) that bind the legumes together.
Although you can buy it at the grocery store, it is easy and safe to make tempeh at home!
Which Legumes Should Be Used to Make Tempeh?
Traditional tempeh is made with soybeans.
However, any legume can be used to make tempeh.
It is therefore possible to make tempeh from:
White beans, black beans, pinto beans, azuki beans, red beans, etc.
Gourganes (or Broad Bean or Fava Bean)
and all the others!
Note that in the FAQ at the end of the article, you will learn that it is also possible to use grains to make tempeh…
Using Dehulled Legumes
This is by far the easiest option!
To make tempeh, the legume shells (teguments) must be removed! Otherwise, the culture cannot penetrate the seed. Therefore, an important step is saved by using legumes that have already been splited, broken, or dehulled.
Place the soybeans in the large bowl and cover with 8 cups (2L) of cold water.
Soak the soybeans overnight (or longer).
Drain the beans, rinse, and discard the water.
If you are not using dehulled soybeans, remove most of the hulls by hand.
Cooking the Soybeans
In a large saucepan, bring 8 cups (2L) of water (unsalted) to a boil.
Add the soybeans to the saucepan.
Cook, uncovered, for about 25 minutes or until the soybeans are al dente.
While cooking, skim off any foam that forms on the surface.
Drain very well.
Adding the Starter Culture
Spread out well the soybeans on a clean dishcloth and rub lightly to dry them off.
When the soybeans are dry to the touch, transfer them to the mixing bowl.
Add the vinegar to the beans. Mix well.
Add the spores. Mix very well.
Fill the bags with the soybeans. Do not pack. Do not exceed 1 inch (3 cm) in thickness. Close the bags.
On a cutting board, spread out the bags and with a fork, poke holes ½ inch (1 cm) apart. More holes are better than less.
Place the bags on a tray or directly on the oven rack.
Turn on the oven light and open the door.
After 60 minutes, check the temperature with a thermometer placed on a bag. If the temperature exceeds 90°F (32°C), then open the oven door slightly more to keep the temperature around 86°F (30°C). Check the temperature from time to time.
After 12 hours, turn the bags over and turn the oven light off.
The tempeh is ready to be consumed when a white film covers the entire soybeans, and the beans form a solid loaf. Fermentation of the tempeh can take from 24 to 72 hours.
Refrigerate or freeze the tempeh to stop fermentation.
Tempeh can be kept in the fridge for about a week. It can be kept in the freezer for several months.
Have you tried it?Share and tag @revolutionfermentation!
How do you eat tempeh?
Here you are, with fresh, beautiful chunks of tempeh ready to be cooked!
Besides being rich in protein, tempeh is also high in fibre. It can easily replace meat or tofu in your meals.
To cook it, be inspired by Indonesian, Asian, vegan, and fusion recipes… or create your own!
Here Are Our Favourite Recipes:
TLT (Tempeh Lettuce Tomato) or TMK (Tempeh, Mayo, Kimchi) sandwich
Asian-style glazed tempeh
In a dragon bowl
In a stew with coconut milk
Tempeh ribs in BBQ sauce
Simply fried in oil
Is tempeh too strong for your taste? Boil it for a few minutes before adding it to your recipes.
Note: Always cook tempeh before eating it.
Avoiding Mistakes and Improving Your Technique
As you can see from the tempeh recipe, making tempeh is relatively simple. However, it is normal to make mistakes at first or to want to improve your technique.
To successfully make tempeh, or to improve your technique, you need:
A good starter culture.
Perfectly clean equipment.
Good control of the incubation: temperature, humidity, and acidity.
Good Tempeh Starter Culture
It may sound obvious, but to produce good tempeh, you need a good starter!
Having a tempeh starter with a high concentration of active spores (example: 8 million spores/g).
Having a tempeh starter with an unexpired Best Before date.
A tempeh starter stored in a cool and dry place (ideally in the freezer).
If your tempeh starter is a few weeks past its Best Before date, add more when inoculating.
It is not recommended to reuse a portion of tempeh as a starter culture (backslopping), as there is a risk of contamination.
To limit the risk of contamination, it is recommended to thoroughly wash and sanitize the equipment that will be in contact with the tempeh culture. Sanitizing destroys microorganisms that are still present after cleaning.
This is especially true if you reuse incubation material (Ziploc bag or other reusable containers), as these may still contain microorganisms after cleaning.
You should pay particular attention to the cleanliness of:
The incubation temperature should be between 80°F and 92°F (27°C and 33°C) to allow for proper growth of the tempeh.
A temperature that is too high could favour the development of pathogenic bacteria, such as Bacillus cereus.
Since tempeh produces its own heat after a few hours of fermentation (it is said to be exothermic), it is important to monitor the temperature. Generally, 12 hours after the start of incubation, the heating is stopped, as the tempeh itself produces enough heat to reach the desired temperature.
Acidity protects against harmful bacteria. It is therefore important to add vinegar when preparing tempeh.
Vinegar can be added at two different times: when soaking the legumes, or when adding the culture.
Even if the acidity of the tempeh decreases during fermentation, it will still be safe, as the enzymes and molecules created by the culture will carry on protecting against harmful bacteria.
Tempeh culture needs oxygen to grow, otherwise, it will suffocate! However, tempeh must not be allowed to dry out during fermentation.
A good level of oxygen is obtained by punching holes in a small Ziploc bag. You also want the beans to have a good texture and not be overcooked and allow air to circulate between the beans.
Depending on the type of incubator, more or fewer holes can be made in the bags or no bags at all.
When bagging, the legumes should not be wet to the touch. Too much water on the legumes promotes the growth of bacteria and slows down the colonization of the tempeh culture.
To remove as much moisture as possible, drain the legumes as much as possible after cooking, then spread them out on a clean cloth and rub them lightly. A fan may be used.
Waiting for the legumes to dry in the open air is not recommended. Too long a waiting time between cooking and inoculating opens the door to contamination.
If you see drops of condensation in the bags during incubation, the beans were probably too wet.
Frequently Asked Questions about Tempeh
Can tempeh be made from grains?
Yes, tempeh can be made from a variety of cereals and grains such as rice, quinoa, millet, barley, buckwheat, sunflower, etc.
You can make tempeh from grains only, or you can mix grains and legumes. Cook the grains al dente in a separate saucepan and drain them well. Add them to the legumes along with the vinegar.
Can Tempeh Be Made Without Starter?
No. Unlike other fermentations such as fermented vegetables, you need a starter culture to make tempeh. You cannot make tempeh without tempeh spores.
It is not advisable to use tempeh as a starter culture (backslopping), as there is a risk of contamination (and intoxication). We recommend always using tempeh spores from a reliable source to start a new recipe.
Can Canned Legumes Be Used to Make Tempeh?
No. Canned legumes are not suitable for making tempeh. They are overcooked and make tempeh taste mushy.
In addition, they contain added salt or additives, which slow down and hinder the fermentation process.
Can I Make Tempeh Without Plastic Bags?
Yes, it is possible to make tempeh without plastic bags!
Resealable plastic bags (such as Ziploc) with holes create an environment that is neither too wet nor too dry, with good air flow.
This environment can be recreated in various ways:
Banana leaves (traditional technique)
Reusable silicone bags with holes
Closed and perforated plastic containers
Open containers can also be used. However, the tempeh may dry out quickly, which may affect the fermentation process. This technique is ideal if you use a hot water bath to ferment the tempeh, or if you can maintain a high level of humidity in your incubator.
Under these conditions, you can use:
A shallow glass dish
Stainless steel catering dishes
If necessary, cover one side with a lid or with perforated aluminum foil to allow air flow.
Why Didn’t My Tempeh Ferment?
If even after 48 hours, your tempeh still doesn’t show any signs of fermentation, there’s a problem!
There are several possible causes:
The legumes were not shelled enough
The incubation temperature was too low or too high
There was not enough air flow
The spores were no longer good or too weak
Don’t be discouraged! With a few adjustments, you can make delicious tempeh.
Why Is My Tempeh Black?
When tempeh ferments too long, black spots appear.
This is perfectly normal and edible! These are tempeh spores.
In Indonesia, very ripe, black tempeh is called Tempe bosok. It is prized for its stronger taste and smell compared to fresh tempeh.
Ripe tempeh may have a stronger ammonia smell. This is normal and safe. Next time, remove the tempeh a little earlier from the incubator.
Why Is the White Part of My Tempeh Uneven?
Sometimes the mycelium does not grow evenly everywhere and leaves parts of the legumes untouched.
Poor air flow in this section or insufficient mixing of the spores may be the cause.
Discard the uncolonized parts and eat the rest.
How Do I Know if My Tempeh Is Good?
Well-fermented tempeh is covered with a white mould and has a mushroom and undergrowth smell with a hint of ammonia.
It is easy to identify tempeh that has not succeeded:
Rancid garbage smell
Slimy or sticky texture
Bright-coloured mould (green, pink, orange, etc.)
It is then recommended to throw it all away.
Are There Any Risks in Eating Tempeh and How Can I Avoid Them?
Some fermentations, such as sauerkraut or kombucha, are protected from pathogens by their natural acidity. However, tempeh does not have this natural defence and precautions must be taken to ensure that there is no contamination.
Don’t panic! Tempeh is much safer to eat than many foods in your fridge (especially if they contain animal products).
Bacillus Cereus Bacterium
The health risk with tempeh is mainly due to the Bacillus cereus bacterium. This can cause indigestion which resolves spontaneously within 24 to 48 hours (ref.).
How to Prevent the Development of Bacillus Cereus?
The optimal incubation temperature for Bacillus cereus bacteria is 98°F (37°C), so it is important not to overheat tempeh during incubation to prevent the growth of the bacteria.
Bacillus cereus does not tolerate acidity, so the addition of vinegar is essential.
Cleanliness of the equipment is required to prevent contamination. Sanitation is recommended, especially if incubation containers are reused.
Having a quality culture also helps to protect against contamination.
What Is Better Between Rhizopus Oligosporus & Rhizopus Oryzae?
There are two main strains for tempeh making: Rhizopus oligosporus and Rhizopus oryzae.
Both cultures can be used to make tempeh at home, but they are slightly different.
The more common culture is Rhizopus oligosporus, which colonizes faster tempehs made from various legumes. However, Rhizopus oryzae is excellent for creating amino acids and processing complex fats from legumes, especially soybeans.
Both strains offer comparable quality results and can be used in any recipe.
Can I Eat Raw Tempeh?
No. We do not recommend eating tempeh raw. Always cook it before eating it.
Most store-bought tempeh is pasteurized and therefore safe to eat raw. Homemade tempeh, on the other hand, should always be cooked to avoid infection by harmful microorganisms.