Making Tempeh

Growing my own tempeh has been on my list of things to try. I have recently received a free sample of tempeh starter from Tempeh Info. So way I go to give it a try. I was a bit nervous to keep a constant temperature of around 30deg C to incubate the beans. I don't want to spend ££ to buy/build an incubator, so I racked my brain and find what I already have at home. I started gathering a few items like an electric plant propagator sitting in the cupboard, an old glass thermometer and a portable light.

If you have a way to keep the beans in a warm area around 30 deg C then an incubator is not required.

To build an incubator (my method)

• a clean electric plant propagator available from most garden or DIY stores. This is the main heat source. (do not use propagator if murky unless it is scrubbed till very clean)
• a rack put inside the propagator tray to enable air circulation on bottom side of the bags during fermentation.
• clean tea towel lining the tray to help absorb any moisture building up in the incubator
• a thermometer to check temperature, able to read 20 - 40 deg C easily. I used a traditional glass thermometer, you can use any cheap thermometer like a room thermometer or a probe.
• portable light with a 40 watt bulb for extra heat when needed.
• some string to tie the light fitting on the inside of the propagator lid. Make sure the light bulb is not in contact with the lid to prevent heat damaging the plastic.
• a small piece of sticky tap to seal the vent on the lid, remove when temperature gets higher than required.
• a clean blanket to conserve heat

Other tools or items required

• large bowl for soaking, cleaning and dehulling beans
• large sieve for collecting bean skins
• colander to drain beans
• large pot to boil beans
• cooking spoon
• 2 plastic ziploc bags to fill the beans and shape the tempeh
• metal/bamboo skewer with pointed tip to prick holes on the bag

Ingredients for tempeh

• 600g dried soy beans
• 4 - 5 tbsp vinegar for boiling beans
• 1 tsp tempeh starter
• plenty of water for soaking, cleaning and boiling beans

Now that I have an incubator, the next thing to do is soak and prepare the soy beans.

Instructions how to make tempeh follow this link.

Here is my step by step slideshow

My incubator heat control

I used two heat sources, one from the electric propagator and the other is a light bulb tied to the inside of the lid. 

 
To conserve heat I also covered the incubator (propagator) with a blanket. 

 
A thermometer put on top of the beans to check temperature. 

 
With all this preparations my incubator has maintained a regular temperature around 30 - 32 deg C for the first 12 hours. 

 
After that I noticed the temperature has risen to about 34 - 35 deg C. I then turned off the light leaving the propagator on only. This has perfectly maintained the right temperature for the remaining incubation time. 

During incubation time, check temperature every few hours or as often as you can. During the first 8 -10 hours the beans need to absorb heat, after that they will give out heat once fermentation is well on its way.

 
If temperature has risen more than 33+ deg C, do any or all of these with my method of incubation

• turn off the light heat source
• remove the blanket
• remove sticky tape to let warm air vented out
• open the lid for few minutes to cool then put it back on and continue.

Seeing the beans growing into tempeh - incubation time

• During the first 8 -10 hrs there was nothing much happening. 
• The beans absorbed the heat from whatever heat source given.
• Gradually as the beans getting warmer condensation seen on the inside on the bags.
• By about 12 - 13hours, temperature rose quite high due to beans giving out their own heat during fermentation.
• By about 18 hours, I saw thin film of white mould on the beans
• By about 24 hours, the white mold has grown much thicker and beans have stuck together forming a firm piece.
• By 30 hours, both bags have become solid matured tempeh ready for harvest. 

Outcome

I was very pleased my first batch of tempeh has turned out to be very successful and harvesting time was much shorter than instruction given by the starter's manufacturer. I will definitely make more tempeh from now on.

The tempeh looked just like a piece of creamy white nougat, no black spots. It has no odd smell quite nice kind of mildly nutty and mushroomy. The white mould feels just like that on a piece of brie.

Yield 2 blocks total weight just under 1kg

One thing I will improve in future is the shape of the tempeh. I will try to make the tempeh thicker into a loaf or log shape block. Maybe I will try wrapping the beans with banana leaf like the traditional method.

Making tempeh is not difficult. The worst job was dehulling the beans which took a bit of elbow grease and time. 

The proof of the pudding is in the eating as they say. I will post the taste test and recipes later.