Tempeh Incubator

Having made one test run making tempeh for the first time at home, I decided I’m going to be making it regularly so I wanted to make a solidly built incubator. After looking around on the net, I ran across a website from a professional tempeh maker that had a pretty nifty incubator setup. (http://www.makethebesttempeh.org/how-to-make-a-tempeh-incuba.html)
I learned quite a bit while making this, and I’m still fine tuning it because of some cheap equipment not functioning as it’s supposed to. I picked up a relatively inexpensive air pump , but after 24 hours of using it the temperature kept being increased by it. I didn’t realize it until the end, when I did some tests and removed the air stone and minute by minute the temperatures dropped. I put it back in, and the temperature increased yet again.


I took one thing from this: Never cut corners on the key components.  I’m repurchasing a water heater & air pump due to my decision to go inexpensive.  I’ve also learned that after 10 hours, the tempeh’s self-created heat from the fermentation will collect quite a bit in this well insulated container.  The water does a great job of distributing the temperature, but I found myself needing to drop ice into the water to bring it down from 92 degrees as it kept climbing higher and higher.  After I purchase a new air pump, I’m going to see how things work out.  Worse case scenario, I will use my geek powers to fabricate a water chiller with temperature controller.

Outside of the incubator, this is how I did tempeh, which will probably change soon:

  • Collect 3 cups soybeans, and crack them in grain mill (I use kitchenaid grain mill on coursest setting)
  • soak cups soybeans overnight
  • rinse soybeans and cook for 30 minutes
  • drain soybeans, and dry them well.
    NOTES: There are many ways to do this, but I’ve done both of these:
    1) put soybeans in bowl, and use a hair dryer on soybeans while stirring, until they are well dried.
    2) Put soybeans into a pillow case with zipper, and put into dryer. (THIS WORKED WONDERFULLY FOR ME)
  • Put dried soybeans in bowl & stir in 1 teaspoon white vinegar very well
  • Put 1 teaspoon tempeh starter culture into soybeans and stir in very well (for 2-3 minutes)
  • Make sure water bath in incubator is at 86-88, and put soybeans into stainless steel hotel pan.  Evenly spread them over the entire pan, patting down.
  • Place pan into incubator, make sure air pump & heater are running, then put the lid of the cambro container back on.
  • Note the time.  10-12 hours later is time to examine and make sure the temperatures are okay.
  • Periodically view the temperature to make sure it doesn’t skyrocket over 91-92 degrees F.  It’s not that it can’t go that high, it’s just not conducive for good growth.
  • After 10 hours, heat will be generated by the soybeans from fermentation.  White coating of mycelium should be visible by 12-14 hours.  It will thicken as time goes on.
  • It is possible to stop at 24 hours, but I recommend 30 hours due to protein fermentation that occurs which makes it taste better.
  • When it’s time, pull the tray and let it cool to room temperature.
  • preheat the oven to 180 degrees, and cook tempeh for 35-40 minutes to pasteurize.
  • Pull from oven, and let cool.  It’s ready to be cut/shaped/used for food!






I have cut tempeh into squares the first time and cooked in a pan.  I’ve decided for now that tempeh will be replacement for hamburger patties & the remains will be chopped and used as filler with anything else being made.


EDIT August 3rd, 2015
I just had some of this tempeh for dinner (a sous vide cooked patty with spices, olive oil, balsamic vinegar) and the smaller sections of soybean made by the Kitchenaid grain mill (quarters instead of just halves) made the patty taste more full and have a great texture.  I prefer it more than the last batch I did with the beans being split in half by hand.  It also was less prone to having a bean slip out when being flipped or moved roughly since it was solidly tied together by the mycelium like this.  The patty also seemed to absorb the marinade quite a bit faster than it did with the last batch.

EDIT August 22nd, 2015
I made a couple of adjustments to the design of the tempeh incubator.  With the temperatures in Phoenix during the summer not being terribly helpful, my house is about 80 while I’m home & hovering between 85-90 while I’m at work.  As you can imagine, this can make the last 12 hour run of tempeh creation a little rough.  What I did was created a make-shift water radiator system.


Above is a picture before I created pass-through holes for tubes & electrical wires.  On the back wall of the cooler, you will see a submersible water pump.  This pump is a bit of an overkill, with 290 gallons per hour ( http://www.amazon.com/gp/product/B0012UZYMG?psc=1&redirect=true&ref_=oh_aui_detailpage_o06_s00 ), but I wanted something that would be scalable to multiple coolers/incubation areas in the future.  I also picked up a miniature radiator for the water to pass through and release the heat into the air.  ( http://www.amazon.com/gp/product/B00CFDS3JA?psc=1&redirect=true&ref_=oh_aui_detailpage_o06_s01 )  The radiator has a vinyl tube attached to it’s intake, which has a reducer ( http://www.amazon.com/gp/product/B003VAUMX6?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00 ) attached to it to connect the pumps tube to it.  The other tube on the radiator goes directly back into the water bath in the cooler.  The radiator has a small 120v powered fan attached to it, ( http://www.amazon.com/gp/product/B00G05A2MU?psc=1&redirect=true&ref_=oh_aui_detailpage_o04_s00 ) which is whisper quiet.

It doesn’t pass much air, but it blows enough air to pass over the radiator fins and absorb heat.  This design was not meant to be excessive in energy movement, as I wanted to keep the temperature motion neutral and not swinging drastically in both directions.  I was originally planning to use a coolant block used in PCs, attach two peltier coolers to it, and an aluminum heat dissipator on the top.  The reason I did not was because it would require a 12v to 120v energy transformer (for one item, why?) and it would be an excessive amount of cool water for 1-3 degrees variation.  Peltiers are great for computer processors at 150-175 degrees fahrenheit, but definitely an overkill for 88-91.


The coup de grace for the entire setup is a temperature controller ( http://www.amazon.com/gp/product/B011296704?psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00 ) with two circuits – one for heating & one for cooling.  This temperature controller has a thermostat which I put into the water bath to measure.  I then attach two power strips to the temperature controller, one on each circuit.  I placed the fan & water pump onto the cooling circuit, the heater is the only thing on the heating circuit currently.  The fish pump is attached directly to the wall since it runs continuously.

After going through the instructions, I boiled it down to setting the temperature I desired (88), the amount of degrees below the temperature I desired that would activate the heating circuit, and the amount of degrees above the temperature I desired that would activate the cooling circuit.  The rest is simply calibrating the thermostat, and setting the “pump standby time” to 0.  I used it with a “hands off” approach today, and things went swimmingly.  The highest I’ve seen the temperature go was 90.3 degrees, and that’s with the controller set to activate the cooling circuit at 90 degrees.
I am planning on expanding the incubator into becoming a pasteurization system for the tempeh, where the temperature would rise to 180 degrees for 35 minutes.  Once that plan is put into effect, it’ll also be capable of being a sous vide system.  That isn’t something I’m trying to do however, since I already have an Anova sous vide system that I use regularly and it works wonderfully.

10 thoughts on “Tempeh Incubator

  1. Gunter would be very proud of you since you followed his instructions to the tee. It is so much fun to read about how people are doing making their own tempeh at home. Unfortunately, Gunter the tempeh guru, passed away on May 2, 2015 to bladder cancer. Gunter who was the great inventor, plant based diet eater, exerciser, etc. was brought down by this terrible disease.
    Love the pictures and if you are ever in the area of Ventura county California come by and we can chat and eat tempeh.
    Betsy Shipley

  2. Betsy, the webpage information Gunter put onto the website was a godsend to me. I’m deeply sorry about his passing, and I’m also very impressed on his scientific way of thinking. Thank you for stopping by my page and letting me know who went through testing and sharing all of that valuable information.
    I’m going to be taking this project further, as well. It’s becoming a pet side project now! If I’m ever heading in that direction, I may well take you up on that.
    Dan Lund

  3. Dan did I tell you that Gunter filed a patent for a smaller size tempeh incubator that could be used in restaurants and small shops making artisan tempeh for the local community? We connected with a group called TempehSure.com who is taking our idea to the next level, meaning they are developing the prototype and will begin manufacturing the incubator early 2016. I suggest if you want information about how far along they are in the project that you contact them at:www.TempehSure.com. Their site gives a brief bio of the key people involved with this project.
    Happy tempeh making
    betsy shipley
    This email would be the best and quickest way of contacting me since I don’t read each tempeh alert.

  4. I hope it takes off, that’s a great idea. It’s also nice to have something available that you can buy to make this wonderful food. It’d look nice in any kitchen, as well 🙂 I’m waiting to see how things go with it!

  5. Thank you for the links! Your guide is a great service to those of us who are not as DIY tech savvy. I have one more question. What is the reducer? I ordered the radiator, the water heater, the external thermostat control, the fan, and the pump, and I have two power strips. I am about to order the two hoses. Am I missing any parts? Thanks!

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