TEMPEH
DO IT YOURSELF

What Is Tempeh?

Tempeh is made through a process known as mould fermentation. Legumes are fermented using a filamentous fungus (Rhizopus oryzae var. oligosporus). As the fungus grows, it breaks down components of the legumes and produces a white network of mycelium that wraps around the beans, binding them together into a firm block. It looks a bit like Turkish delight – but it's tempeh!

Fermentation changes the structure of the legumes, making certain nutrients easier to digest and absorb. Depending on the microorganisms involved, the process can also influence vitamin content, including certain B vitamins and vitamin K2, and produce compounds with antioxidant activity.

Tempeh is traditionally made from soybeans, but many other ingredients work beautifully too: chickpeas, lentils, different types of beans, grains and pseudocereals.

How Does Tempeh Differ from Other Mould-Fermented Foods?

The fungus Rhizopus oligosporus gives tempeh its distinctive flavour, often described as nutty and slightly cheesy.

We like to compare different fermented foods to familiar types of cheese: koji reminds us of cream cheese, natto of blue cheese, and tempeh, thanks to Rhizopus oligosporus, belongs firmly in the Camembert category.

How to Prepare Tempeh

Tempeh is usually fried. Although it can be eaten without further cooking if it has been properly prepared and made ready to eat, we strongly recommend cooking it – it tastes SO much better!

Simply fry it in a pan with a little oil until golden brown, or deep-fry it like French fries. Don't forget to season it! Our favourite way is with a splash of soy sauce.

What's the Difference Between Tempeh and Tofu?

Unlike tempeh, tofu isn't fermented. If we were to compare them to dairy products, tofu would be curd cheese, while tempeh would be Camembert.

Compared with tofu, tempeh generally contains more fibre and often more protein per 100 g, although the exact nutritional values depend on the products being compared.

Fermentation also breaks down certain compounds in the beans, which may improve digestibility and nutrient availability. However, this does not automatically mean that tempeh contains probiotics or has a proven beneficial effect on the gut microbiome.

MAKING TEMPEH AT HOME
INSTRUCTIONS / TIPS AND TRICKS

Step-by-Step Guide to Making Tempeh

Mould needs air, warmth and moisture to grow. Before getting started, it's important to create the right conditions at home.

You can build a simple home incubator without spending much money. If you just want to give tempeh a try, an oven can also work as a makeshift incubator, provided you can maintain the correct temperature.

For those who get hooked, here's our guide to building your own incubator.

Step 1: Soaking

Soak your chosen ingredients – soybeans, chickpeas, lentils or whatever else you're using.

Soaking time depends on the size and type of ingredient. Soybeans, chickpeas and most beans are best soaked overnight, while smaller grains and pseudocereals such as millet, amaranth and quinoa need much less time – often no more than an hour.

Step 2: Cooking

Now cook your legumes until al dente.

Discard the soaking water and cook the legumes in fresh water until tender but still firm to the bite. You can add a little vinegar to the cooking water, which can give the finished tempeh a more pleasant flavour.

Don't overcook the beans. We still want something to chew on!

Step 3: Inoculation

Next, it's time to inoculate the substrate. In other words, we're introducing the fungal spores to our cooked beans.

All you need is your tempeh starter and a spoon.

Dosage: 10 g of our tempeh starter is sufficient for 5 kg of cooked substrate.

Before inoculating, make sure the legumes have cooled to below 35°C and that their surfaces are dry.

The easiest way to do this is to spread them out on a clean kitchen towel after cooking and gently pat them dry.

Then transfer the beans to a dry bowl. Don't add the starter while they're still on the damp towel – otherwise, the spores will stick to the fabric instead of the beans.

Sprinkle the starter evenly over the beans using a spoon or a small sieve.

Mix, mix and mix again!

Every bean should come into contact with the spores.

Step 4: Packaging

Tempeh mould needs oxygen to grow, so we have to make sure air can reach the beans during fermentation.

There are several ways to do this.

One simple option is to use a food-safe plastic bag and perforate it with a toothpick. Make small holes approximately 1 cm apart across the bag.

If you make tempeh regularly, our pre-perforated tempeh bags are a more convenient option.

You can also ferment tempeh in glass or stainless-steel containers.

The important thing is to keep the layer of beans no thicker than 5 cm and ensure adequate airflow. Do not seal the containers airtight.

Step 5: Fermentation

Place your tempeh in the incubator.

Incubation conditions:

Temperature: 30°C
Relative humidity: approximately 85%
Initial incubation time: around 24 hours

After about 24 hours, you should begin to see a white layer of mycelium developing.

Depending on the temperature, humidity, substrate and activity of the starter culture, fermentation may take longer.

Your tempeh is ready when white mycelium has grown evenly throughout the beans.

Often, the mycelium binds everything together into a firm tempeh cake. How well this works depends partly on the type and size of the beans.

But don't worry: not every single bean needs to be perfectly bound together.

Keep an eye on the temperature inside the tempeh itself. As the mould grows, it generates metabolic heat, so the temperature of the beans can rise above the incubator's set temperature.

Step 6: Harvesting

Remove the finished tempeh from the incubator and cool it down promptly in the refrigerator.

Tempeh is at its best when it's fresh, so we recommend enjoying it soon.

For longer storage, freeze it in portions.

And don't forget to cook your tempeh thoroughly before eating it.

Anleitung Schritt für Schritt Tempeh selber machen

MAKING TEMPEH AT HOME
FAQs

Which Legumes Can Be Used to Make Tempeh?

Almost any legume can be used to make tempeh. It also works with grains and pseudocereals such as quinoa and buckwheat.

Two things are particularly important:

Nutrient content: The substrate (the beans or grains on which the tempeh mould grows) needs to provide sufficient nutrients to support fermentation.
Accessibility: The mould needs access to the nutrients inside the beans. This is why beans should ideally be dehulled, split or cracked before fermentation.

Can I Use Other Spores to Make Tempeh?

No. Traditional tempeh is made using specific Rhizopus mould cultures. Using a different type of mould would result in a different fermentation process and potentially an unsafe product.

How Long Does Tempeh Keep?

Fresh tempeh is best enjoyed as soon as possible after fermentation, when its flavour is at its finest.

When properly refrigerated, fresh tempeh may keep for around 7–10 days, depending on hygiene, packaging and storage conditions. Homemade tempeh should be cooled promptly and kept refrigerated. Refrigeration slows fermentation but does not stop it completely.

Tempeh also freezes very well, making freezing an excellent option for longer storage.

Is Tempeh Healthy?

Yes! Tempeh is generally considered a nutritious food and offers several nutritional benefits.

Protein: Tempeh is an excellent source of plant-based protein and contains all nine essential amino acids. It is a particularly interesting option for vegetarians and vegans.
Fibre: Tempeh made from whole legumes contains dietary fibre, which contributes to normal digestive function.
Fermentation: During fermentation, the mould breaks down certain components of the beans, potentially improving digestibility and the availability of some nutrients. However, tempeh should not automatically be considered a probiotic food.
Vitamins and minerals: Depending on the ingredients, tempeh can provide iron, magnesium, phosphorus and other micronutrients. Vitamin B12 is not reliably present in tempeh and should not be assumed to be a significant nutritional source.
Fat content: Tempeh contains mainly unsaturated fats, although the total fat content depends on the legumes or grains used.

How Do You Cook Tempeh?

Here's one of our favourite ways to prepare it:

Cut the tempeh into slices, cubes or strips.
Heat a little oil in a frying pan over medium heat.
Add the tempeh and fry until golden brown and crispy on both sides.
Add a splash of soy sauce, followed immediately by a little water. Soy sauce burns easily, but the water creates a delicious savoury glaze that coats the warm tempeh.

Tempeh is wonderful with kimchi or other fermented vegetables. A fresh salad also makes a lovely accompaniment.

Alternatively, tempeh can be deep-fried, grilled or roasted in the oven.

Always cook homemade tempeh thoroughly before eating.

Do I Need Special Equipment to Make Tempeh at Home?

Yes, a few things are essential.

Besides tempeh starter spores, you need the right conditions for fermentation: high relative humidity (around 80%) and a temperature of approximately 30°C.

During summer, tempeh fermentation may occasionally work at room temperature — although who really wants their home to be 30°C?

In winter, you'll generally need some kind of incubator to maintain a stable temperature.

You'll find a few ideas in our guide: How to Build a Tempeh Incubator.

TEMPEH TROUBLESHOOTING

Help, Mould!

Great! That's exactly what we wanted.

Tempeh is made with mould, after all. Small grey or black spots can be perfectly normal. They often appear around the air holes in the fermentation bag, where moisture and oxygen levels can encourage sporulation.

Help! My Tempeh Has Black Spots!

Black mould usually sets off alarm bells. But with tempeh, things are a little different.

When tempeh ferments for too long or gets too warm, the Rhizopus mould begins to produce spores. This is called sporulation — the mould's way of reproducing.

These spores are grey to black. In an otherwise healthy tempeh fermentation, a few dark spots caused by the tempeh culture itself are generally harmless.

Black spots often develop around the air holes in the fermentation bag, where condensation and exposure to oxygen can influence mould growth.

If the entire tempeh turns grey or black, it is usually a sign that fermentation has gone too far. Remember, tempeh generates its own heat during fermentation, which can accelerate the process.

A few grey or black spots? Usually no problem.

Completely dark, heavily sporulated tempeh? Overripe. Best to discard it.

However, colour alone cannot tell you whether a fermentation is safe. If you are unsure whether the growth is from your tempeh starter or an unwanted mould, discard the batch.

Pink, red or other unusual coloured mould? Discard it!

No Mould Growing on My Tempeh?

If your tempeh isn't developing its characteristic white mycelium, several things could be responsible:

The beans or grains were too hot when you added the starter.
The substrate was too dry — perhaps the beans weren't soaked or cooked long enough.
The starter spores were no longer viable, too old or improperly stored.
The incubator was too cold or too hot.
There wasn't enough oxygen during fermentation.
Too much vinegar was added to the cooking water.