Homemade Soybean Tempeh

I will admit that tempeh scared me.  The idea of letting soybeans grow mold was one step further than my usual level of fermentation.  Like natto, cheese and cured meats, it was a ferment that I had been blissfully ignoring… until someone arrived on my doorstep 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 surprisingly – amazingly – incredibly delicious. The flavour was completely different from store bought tempeh.  It was both nutty and creamy at the same time, more like eating edamame than the dense tempeh that I had bought in the supermarket.

I had become a master of the mold.

What is tempeh?

Tempeh is 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 more easily digested.  Tempeh is also 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, try it thinly sliced it for a Reuben sandwich, barbecue it, or dice it up for a stir fry.

Tempeh Basics

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. Don’t forget to make your own starter to save for future batches.

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 kept warm 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 will kill the spores.

Dehulling 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 split in half, 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 so that the hulls can float .  Massage the beans to loosen up all the hulls, then drain off the floating hulls.  You may need to do massage the beans for hulls several times to make sure that you’ve gotten 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 will 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.

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Soybeans in the bag with the mold spores 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.