I will admit that tempeh scared me. The idea of letting soybeans grow mold was one step further than my usual fermentation. Like Natto, Cheese and Cured Meats, it was a ferment that I had been blissfully ignoring… until someone arrived on my doorstep last month with a package of tempeh culture and a piece of advice about how to save the spores.
So I took courage… and read everything I could on making tempeh… then I made my first attempt. The results were amazingly delicious. The flavour was complete different and nicer than store bought tempeh. It tasted nutty and creamy at the same time. It was more like eating edamame than the flavoured tempeh that I had bought in the past.
I had become a master of the mold.
Now for anyone who isn’t entirely sure of what tempeh is, it’s an Indonesian dish where a mold culture is used to ferment soybeans until it forms a cake. The fermentation process is not only delicious, it also turns the soy beans into a complete protein that is easily digested. Also tempeh is more likely to be tolerated by those who have trouble with soy (tofu, edamame and other unfermented soy products).
Tempeh has a nutty flavour that is delicious all on it’s own. However, it can be smoked, marinated or sauced which allows for all sorts of interesting flavour options. If you are uncertain about how to cook tempeh, I have a few ideas. Try it thinly sliced it for a Reuben sandwich, barbecue it, or dice it up for a stir fry.
Cleanliness: I will admit that making tempeh is not easy. There are a number of steps involved and you need to keep things clean as you go along. You don’t want to accidentally grow the wrong type of fungus.
Culture: You might be able to find the starter at an Indonesian grocery store, however, you can also find it online.
Dehulling the Soybeans: The hulls of the soybeans need to be removed in order for the spores to inoculate the beans.
Dry method: If you have a grain mill or a meat grinder, then you can pass soybeans through on the coarsest setting. You want the beans to just be split, so if it’s coming out too fine then this won’t work with your grinder. Once the beans are split put them into water, and the hulls will float. Massage the beans to loosen up the hulls, then drain off the floating hulls. You may need to do this several times to get rid of all the hulls.
Soaking method: Soak the beans for at lest 12 hours. Then with your hands or a potato masher massage the beans so that the hulls fall off and the beans split in half. The hulls float to the top, so drain off the floating hulls as you go. This is quite time consuming, so if you find yourself making tempeh a lot, then I’d suggest that you buy a grain mill.
Fermenting Container: The tempeh needs to be loosely spread out, about 2 cm deep in a vented container for fermentation. You could use a vented plastic container, a baking pan covered with plastic wrap with holes poked in it. However, the easiest way to make tempeh is to use a plastic bag with needle holes poked through at 1 cm intervals.
Incubation Options: The other tricky part about making tempeh is that the starter needs to be incubated at around 85-90 F. Luckily I have my Brød & Taylor Bread Proofer & Yogurt Maker which works well for all my heated ferments. Other options include incubating in the oven with the light on, near a radiator, or a hot water heater. Many people use dehydrators set on the right temperature for incubation. You could also use a cooler with jars of water heated to the right temperature.
The only trick is to measure the temperature as you go along, because tempeh starts to self-generate heat as it ferments. The right temperature is important because if it’s too cold your mold won’t grow, and if it’s too hot you’ll kill the spores.
- 1 lbs dried soybeans (2½ cups)
- 2 tbsp white vinegar
- 1 tsp tempeh starter
- Cover the soybeans with water and soak for 12 -18 hours (even if you use the dry method for dehulling).
- Bring the soybeans to a boil and simmer, until the beans are soft but not mushy, (about 1 hour).
- Drain the beans and gently pat them dry with a towel, then allow them to cool to just below body temperature.
- Mix the vinegar with the beans (to lower the pH so that unwanted bacteria won't grow).
- Sprinkle on the tempeh starter and mix well so that the beans are evenly covered by the spores.
- Fill the fermentation containers.
- Incubate at approximately 88 F (31 C).
- Check the beans after 12 hours. At this point the mold will have started to grow and the beans will start generating their own heat, so you may need to lower the temperature.
- At some point between 24 and 48 hours your tempeh will be finished. You know it's done when the mold has thickened the tempeh into a single dense mass. (There might be some grey or black mold too, but you want to stop before there's too much black mold. See photos below).
- At this point stop the fermentation by transferring to an airtight container and refrigerating for up to 1 week (see notes for cooking and freezing instructions).
-Tempeh can be eaten raw. However, I prefer to steam it before eating. Steam it for 20 minutes in a steaming basket, or with a colander over a pot of boiling water.
-Tempeh can be frozen for up to three months, but you will need to steam it first.
-The black and gray spots on the tempeh are the mold spores and they are completely edible. The tempeh should smell nutty, mushroomy and it might have a hint of ammonia. If it smells bad, is mushy or slimy then throw it out.
Here is my tempeh mixed in the bag before incubation.
Here is the tempeh after 30 hours (still in the bag). You can really see the mold fibers!
And this is what the tempeh looks like after it’s been steamed.