Oliver, thanks for your easy, practical solution for a food incubator, that as you show, works very well. I'd add only that perhaps the light bulb would be more advantageously place at the bottom, under the rack, in order to enhance and uniformize the convective heat transfer in the air volume. I realize this may not matter much because the Styrofoam is such a good insulator and heat loss to its walls are minimal, which would otherwise cause temperature nonuniformities. You went after the simplest construction but I on the other hand went for a more compact/dedicated approach, with some unique features. I wound up gluing together 3/4 inch thick plain rigid Styrofoam and I installed two simple racks inside using 1/8 inch dia stainless steel rods. The overall dimensions are a little over 12 x 12 inch^2. The rods are spaced to accommodate "snack" size plastic storage bags. This way, out of one batch of 1.5 lbs dry beans, I get about a dozen separate meal-size portions 6 rods in each of the two rows. The bags are hung from the rods, as the rods penetrate through the top of the bags, just under the bag seal, with plenty of air around each bag.. I also put a very small centrifugal fan at the bottom, with the cord penetrating the side of the Styrofoam at the bottom. The fan is only 5 Watt RMS, and it's just what I need only when I first load up the box. After a short time, starting with the beans at about 80 F (recommended fermentation temperature is about 80 - 90 F), the temperature INSIDE the bags - the beans themselves, not the air around them - starts increasing because of the fermentation heat release. I then unplug the fan and the beans have been staying in the desired temperature range. I measure temperature with a Type K thermocouple wire inserted in one of the bags. I don't like the idea of using plastic bags and would much rather use the traditional banana leaf. But that will be a next improvement, and I do re-use the plastic bags. With the plastic, I find that you need to poke sizeable holes through the sides, roughly an inch apart, and a diameter minimum 1/8 inch or more. Otherwise, the beans can stay a bit too moist, suggesting that you really should dry them before fermentation. The last batch I mad took less than a day to ferment. NOTE: from the suggestion of Contain Rain, below, I think humidity in the air in the box is important, and so I make the following modifications: Rain, this is an excellent question and it illustrates the one feature of the traditional banana leaves method that Oliver's (and mine) method leaves out. In fact, I didn't think of it, and you're right, the tempeh I make seems too wet. What I need to do is to put more holes in the plastic bags and put some holes in the Styrofoam sides, and probably keep the fan on all the time (5 W RMS) in order to keep the humidity low in the box. This will require experimentation to get it right, and thanks much. Enjoy Tempeh, and thank those past Indonesians for being so clever, intelligent, and responsive to the many ways Nature wants to help us, despite the horrible violence many of us now display to each other and to Nature itself.

Nice presentation. Thanks a lot.

Thanks to your wonderful video. Now I have my own yogurt, natto, and tempeh incubator = Hamilton crock pot (keep warm) + Willhi temperature controller.

I just use a cooler, temperature controller and a seed germination heat pad. I use what I have on hand. Light in a tin can can be another source of heat, but for a small space, what I have is enough.

That's really awesome man! Great video

Really nice way of story telling and tone.

I made a similar incubator, but I found the cheap temperature controller was poorly calibrated and overheated the tempeh. So, I used my Sous Vide cooker placed inside the box as a heat sources and temperature controller instead it worked very well.

there is also one other web site with pvc pipes to move the water...have to locate it again.

Some great ideas her mate But tempeh takes 12-15 hours to ferment(Plus many hours outside the box at room temp) to ferment Are you able to be there for the entire 12-15 hours monitoring constantly?

Sorry about my post being in bites. They should be all together as the people actually are together www.tempehgirls.com/2016/10/26/tempeh-nachos/ . It is due out this August due to some nice redesigning they did. Their is a video on it too with recipes and blog.

show us the tempeh you made with your incubator!

How do you handle humidity?

Now, it's time to sell the kit on eBay.

Styrofoam cooler would be less trouble

Why didn’t you get a dollar store cooler?

Thank you for is to ser