How to make tempeh with our tempeh culture
Jeff and I attended a Tempeh residential in Yogyakarta, the heart of Java - and not only did we take a deep dive in tempeh making in all shapes and sizes and with different mediums, and in very humid weather with steaming pots and frying pans around - we ate a lot of tempeh - fried crisp as a Tempeh Mendoan with sambal, steamed in banana parcels, crumbled into coconut-rich curries. Our favourite way is taking a freshly made round block, slicing it and frying it - see below. That's it. So delicious. Making your own could be the only way you'll experience that real, fresh tempeh flavour here in Australia - most stores will only stock frozen or pasteurised however you might find a maker at your local market.
Check out our sausage style shape we made... we also made burger shapes and blocks.
The sausage one was sliced and fried golden - so so good.
OK, so on to making Tempeh
Tempeh is a traditional Indonesian fermented soybean cake bound together by white mycelium from Rhizopus oligosporus cultures. The fermentation transforms cooked soybeans into a firm, sliceable cake with an earthy, nutty flavour and remarkable nutritional density. Unlike many ferments, but as you'd expect with mycellium, (think Koji) tempeh requires temperature control (around 30°C/86°F) and needs humidity. It will develop within 24-48 hours. This is perfect for summer in Australia - you might not even need an incubator! This is one of those protein ferments that you cook - and benefit from the fermentation in a different way - the tempeh is already 'pre-digested' and nutrients more readily available. It's also very delicious.
Ingredients
- 500g dried soybeans (organic preferred)
- 2 tablespoons vinegar (white or apple cider)
- 1-2 teaspoons tempeh starter culture (Rhizopus oligosporus)
Equipment
- Large pot for cooking
- Colander
- Clean tea towels
- Perforated bags (or ziplock bags that you'll poke holes in) or banana leaves - best!
- Incubation setup: insulated box, heating pad, or dehydrator set to 30°C (or a hot muggy day)
- Thermometer
Method
Prepare the soybeans: Soak your soybeans in plenty of cold water for 8-12 hours or overnight. They'll nearly double in size. This step softens the beans and begins breaking down some of the complex sugars.
Dehull the beans: Drain and rinse the soaked beans. Now comes the satisfying part - you need to remove most of the hulls. Rub handfuls of beans vigorously between your palms or knead them firmly in the bowl. The skins will split and float to the surface. Fill the bowl with water, agitate gently, and pour off the floating hulls. Repeat this process several times. Don't worry about getting every single hull - aim for about 90% removal. The hulls can interfere with the mycelium binding the beans together.
Cook the beans: Split the dehulled beans in half by squeezing them gently (this increases surface area for the culture). Place them in a large pot, cover with fresh water, and bring to a boil. Reduce heat and simmer for about 30-45 minutes until the beans are fully cooked but still hold their shape - they should be tender enough to squash easily between your fingers but not mushy. Undercooked beans won't ferment properly; overcooked beans create excess moisture.
This is how two of the producers we visited in Yogyakarta cooked their beans - I think in the case of you making it now? Start with a smaller amount, in a regular pot ;) But there is romance in cooking over wood.
Dry the beans thoroughly: This is crucial. Drain the beans well and spread them on clean tea towels. Pat dry and let them air-dry for 20-30 minutes, tossing occasionally. You want them quite dry to the touch - excess moisture is the enemy of good tempeh, encouraging unwanted bacterial growth instead of the desired fungal fermentation. The beans should still be warm (not hot, not cold) when you inoculate.
Acidify and inoculate: When the beans have cooled to body temperature (around 35°C or lukewarm to touch), stir through the vinegar - this lowers the pH, creating an environment where the tempeh culture thrives and competitors struggle. Sprinkle the tempeh starter evenly over the beans and mix thoroughly for at least a minute. Every bean should have contact with the culture.
Pack into containers: Transfer the inoculated beans into your prepared bags or containers. If using ziplock bags, fill them about 3-4cm deep and flatten to create an even layer - this ensures uniform heat distribution. Using a sterilized needle or pin, poke holes every 2cm or so across both sides of the bag. These holes allow the mycelium to breathe (it's an aerobic organism) and release metabolic heat. If using banana leaves, wrap the beans in a parcel tied with kitchen string and pierce holes throughout.
The beans still feel loose as you're putting them into the bags, almost feels like.. how is this going to work? If you look carefully you'll see there are lots of little holes in the bags in the first photo.
. You can do this yourself...below is the tool that one of the producers used. 
With this burger shape above - we used silicone mats to cover the tempeh to keep it warm and not dry it out.
One of the producers we visited used Jack beans and teak leaves - if you can get banana leaves do it! Much better than plastic!
Incubate: Place your packets in your incubation chamber set to 30°C (86°F). The first 12 hours are critical - the culture needs to establish itself before competing organisms can take hold. During this time, you'll notice the bags may fog up slightly from metabolic activity.
This is no longer a fridge - but an incubator - you can fashion one yourself in containers with heat mats or hot water bottles etc. Setting ourself up with a little incubator sure does make it easier. At home, we have a small insulated locker we made for our koji, and an old bar fridge we use for other things.
Monitor the fermentation: After about 12-16 hours, you'll see the first signs of white mycelium forming, usually starting around the air holes. By 24 hours, the beans should be partially bound together. By 30-36 hours, you'll have a firm cake of beans completely covered in white mycelium. Some grey spotting is normal, especially where the mycelium is very thick. Black spots indicate sporulation - the culture making spores. This is edible but indicates the tempeh is fully mature.
Cool and store: Once the tempeh is firm, bound together throughout, and has a pleasant mushroomy aroma, remove it from the incubator. Let it cool to room temperature, then refrigerate. Fresh tempeh will keep for about a week refrigerated, or you can slice and freeze it for several months.
Our blocks were beautiful and strong
The Jack beans in teak leaves after a couple of days.
Troubleshooting
Beans won't bind together: Usually caused by excess moisture, insufficient culture distribution, or temperature fluctuations. Make sure beans are truly dry before inoculating and maintain steady temperature.
Ammonia smell: The beans fermented too long or temperatures were too high. The tempeh is past its prime but still edible if the smell isn't overwhelming.
Yellow or pink colouration: Contamination. Discard and troubleshoot your sanitation and drying steps.
Slow fermentation: Temperature likely dropped below 28°C. Try to maintain 30°C consistently, especially in the first 12 hours.
Variations - Beyond Soybeans:
Once you've mastered soybean tempeh, you can experiment with other legumes (black beans, chickpeas) or grains (barley, quinoa). Many Indonesian makers blend soybeans with other ingredients or use other stronger beans and wild rice. Just maintain similar moisture levels and adjust cooking times for your chosen base ingredient.
- Black beans (sweeter, earthier flavour)
- Chickpeas (nuttier, firmer texture)
- Split peas (traditional in some regions)
- Mixed beans and grains (adding barley, rice, or quinoa creates interesting textures)
- Lupini beans (if you're in WA, these make excellent tempeh!)
Cooking Your Tempeh - for Tempeh Mendoan see here
Fresh tempeh needs cooking before eating. Here are some favourite preparations:
Marinated & Pan-Fried (the gateway method):
- Slice tempeh 1cm thick
- Steam for 10 minutes (improves digestibility and flavour)
- Marinate in: tamari, ginger, garlic, sesame oil, rice vinegar, maple syrup
- Pan-fry until golden and caramelised
Tempeh "Bacon":
- Slice thinly (3-5mm)
- Marinate in: tamari, smoked paprika, maple syrup, liquid smoke
- Fry until crispy
Crumbled for Bolognese or Tacos:
- Crumble or pulse in food processor
- Sauté with onions, spices
- Add to tomato sauce or taco filling
Grilled Tempeh Steaks:
- Cut into thick slabs
- Score the surface for marinade absorption
- Marinate in your favourite flavours
- Grill or BBQ until charred
Indonesian-Style (how it's traditionally eaten): see Tempeh Mendoan
- Cut into chunks or thin slices
- Deep fry until golden and crispy
- Serve with sambal and rice
Quantities & Flavour Ideas:
Basic Marinade Formula:
- 3 tablespoons tamari or soy sauce
- 1 tablespoon rice vinegar or lime juice
- 1 tablespoon maple syrup or honey
- 1 teaspoon grated ginger
- 1 clove garlic, crushed
- Optional: sesame oil, chilli, herbs
Storage of Finished Tempeh:
- Fridge: Up to 7 days wrapped in paper or breathable container
- Freezer: Up to 3 months (slice before freezing for easy use)
- Fresh tempeh continues to ferment slowly – small black spots are just spores developing
Need a Break? That's Completely Fine
Your tempeh culture will keep for months in the pantry, however I tend to keep mine in the freezer. There's no pressure to make batch after batch – just store it away and it'll be ready when you are. Life gets busy, and your culture understands.
The beauty of tempeh is its transformation - you're not just preserving soybeans, you're creating something entirely new, with enhanced digestibility, reduced antinutrients, and complete protein. The mycelium pre-digests the beans while adding its own subtle flavour and nutrition.
