Tempeh #2

Let me show you how my first batch of tempeh came out, and how to start a new one:

Rhizopus oligosporus mycelium beginning to grow.

24 hours after the tempeh workshop–right on time–I began to see the white mycelia of Rhizopus spreading and beginning to bind together the soybeans.

33 hours after inoculation.

By 11pm that evening, most of the surface of the beans was covered by the downy fungus. I probably could have left it longer, but I wanted to go to bed, and didn’t want the tempeh to become over-mature. (I started my new batch, see below, a little earlier in the day to avoid this problem.) I put it in the fridge until I wanted to use it, a couple days later. (No photos of that because we were too hungry to remember to take a picture. But we made this, and it was good.)

The finished tempeh!

The finished tempeh was good and firm. It sliced well–I could have sliced it very thin without it crumbling. It smelled sort of like bread or fresh, earthy mushrooms. It was dry and not slimy at all. These are all the qualities you are looking for. If anything seems off, toss it and start over. As Papah said at the tempeh-making workshop I attended last week, Rhizopus oligosporus is basically like the mold that grows on bread. (In fact, Rhizopus is a genus that includes a few molds that grow on bread and fruit.) But unlike those molds R. oligosporus is a “friendly” mold! When you meet it, you will know it’s good to eat!

Soaked, cracked and hulled soybeans, ready to cook.

Well, that batch was inoculated by Papah at Bandung. All I did was incubate it. I’ve now started a new batch from scratch. I began with already cracked and hulled soybeans that I got at the workshop. If you can only find whole beans (which I will also have to use when these run out) you’ll have to squeeze the beans to remove as many hulls as possible. Yesterday, I covered about a pound (a little under 2 cups) of the dry beans with water, brought it up to a boil, and then took it off the heat to soak for about 6-8 hours. You could just soak them over night. By this time they were still crunchy and inedible. Then I boiled them for about 45 minutes, until they were just cooked through. You do not want them to get mushy, as the process of fermentation softens them  bit more.

Add 1Tbs vinegar to the beans and dry them.

Then I drained the beans and added a tablespoon of vinegar. This will help create an inviting environment for Rhizopus, but not other microorganisms.

Next is a very important step: dry the beans. I used a towel and, following Papah’s suggestion, a hairdryer. You want the beans to be just dry to the touch. Papah described it this way: you are trying to grow Rhizopus, and the beans are like the soil in a garden. It can’t be too wet. The moisture the Rhizopus needs is inside the beans, not on the surface, or it is too waterlogged. Wet beans are a common cause of tempeh failure.

When the cooked beans have cooled and are dry, add 1/4 tsp of the culture.

When the beans are dry on the surface, add 1/4 tsp of the tempeh culture (or follow package instructions–I think some manufacturers add filler to help it spread). You can buy the culture here, they even have free samples! Make sure you sprinkle the culture evenly, and mix gently so that it is spread throughout the beans.

Close up of holes in plastic bag.

Add the inoculated beans to a plastic bag that has been pierced full of holes.

Ready to incubate.




Now, prepare your container. Using a needle or a skewer, poke holes into a small ziplock bag–about half inch apart. This will allow the tempeh to “breathe.” Without circulation, moisture can build up on the surface of the tempeh and make it go bad.

Fill the bag with the inoculated beans and flatten into the thickness that you want your temph to be. You can fold over an edge of the bag to make thicker tempeh. I put my tempeh on a cooling rack on top of a cookie sheet, and into my gas oven. With the oven off and the door propped open, the temperature stays around 85°.

I will be checking the temperature through the day to make sure it doesn’t get too high–trying to keep it below 90°. As the tempeh ferments, it creates its own “body heat.” If it gets too hot it can kill the Rhizopus, or create too much condensation and produce poor-quality tempeh.

This is the first batch of tempeh that I’m making from scratch, so wish me luck and check back in a day!


Venturing into tempeh

Tempeh (image from wikimedia commons)

Today I had to good fortune of attending a workshop on making tempeh at Bandung Indonesian Restaurant. I’ve never made tempeh before–the need to purchase spores and to maintain a relatively high constant temperature during fermentation mean that tempeh is not necessarily a project for beginners. So, I would try making yogurt (coming soon!) first, to get acquainted with controlling fermentation temperature.

Bandung’s tempeh-master “Papah” Mochammad Sjachrani showed us the steps and gave tips based on his 15 years of experience. We got to see, smell, and feel the difference between good and not-so-good tempeh. I went home with a stomach full of the best tempeh I’ve ever had, and the supplies to make my first couple of batches.

Papah's tempeh instructions, ~2 tsp of tempeh starter, 2 lbs of cracked and hulled dry soybeans, and a small bag of cooked and inoculated soybeans

Basically, tempeh is made by inoculating cooked and patted-dry soybeans (hulls removed) with Rhizopus oligosporus. The inoculated beans must be placed into a breathable  form (in this case a ziplock bag with small holes poked into it) and incubated until the Rhizopus mycelium bind the beans together into a firm cake.

I’ll show you all the steps in detail in a future post. For now I’m just waiting for the pre-inoculated soybeans that I brought home to blossom into delicious tempeh. Papah suggested to aim for 72-74°, and to look for finished tempeh in 48-72 hrs. This will allow me to practice the trickiest part of the process, without having to go through all the labor of the earlier steps the first time.

My first attempt at a tempe-incubation set-up: cooling rack on cookie sheet...

I’ve had plenty of luck using my gas oven, turned off, to incubate yogurt. I think it is probably the most constantly warm place in the house, so I will give this method a try. To give the tempe good circulation, I’m placing it on top of a cooling rack on a cookie sheet.

An instant-read thermometer says it’s in the right temperature range (though maybe a little low)–I’ll keep checking over the next few hours to make sure. If it stays too low, I’ll try turning on the oven for a few seconds.

...and into the oven (turned off!)

Come back here in a couple of days to see if my tempeh has come alive!