How to make a cheap and easy tempeh incubator.
Parts used: 20qt storage bin, thermometer, weatherproof snap in socket, 40 watt light bulb, plastic junction box, electrical cord, non-breakable plate cover, steel plate and a dimmer switch.
Tools needed: Stanley knife, drill, wrenches/drivers; tin snips
Junction joined with bolts. Hole cut out for the socket.
Snap socket snapped. Into place.
Secure the wire clamp, and then insert the power cord.
Connect wires. Use electrical tape to secure the caps.
Romex sheathing was used to hold the cord securely.
Secure the switch in place. Exposed metal should be covered with electrical tape. That is, the back-side of the switch plate, in this example, should be completely covered with electrical tape.
The incubator is now fully functional. However… A few modifications were made after the trial run. The first was to shield the lid above the bulb. Several layers of aluminum foil and paper towel were used, secured with 2-way tape.
The other initial change was to hook the thermometer over the side, instead of using 2-way tape. I cut a thin strip of metal, bent it to hook over the edge, and hold the thermometer – secured, covered with duct tape.
A heat shield was also fabricated from the metal plate, to more evenly dissipate the heat, attached over the bolt ends.
The tray and rack were added in an attempt to avoid using plastic bags. The box was insulated using bubble packaging that the tray arrived in, along with some shop towel and more duct tape.
The setup keeps the temperature very stable, starting out at 85F, quickly rising to 90F with full bulb output, then held steady at 89F at about three-quarters power. The first day it fluctuated between87F and 90F as we adjusted the dimmer, then, by the end of the day it had been honed in right where we wanted.
All in all it’s worked very well. The first two trials with just the tray (Credit for that idea, here), seemed to dry out on top, and the top was not fully ensconced. I gave up on that idea and just use well-perforated, plastic bags.
There are many sites out there with instructions and suggestions. The basics are there: Soak the beans (2.5cups), hull the beans, cook the beans, and dry them well.
Then, it’s 2 tablespoons of vinegar and a teaspoon (Or, in the current case one packet) of the starter mixed with the beans.
Temperature in the incubator should stay between 85f and 90f, and i usually aim from right in the middle of that.
Per the advice of Betsy Shipley – and not seen elsewhere – I’ve taken to baking the cakes at 180F for 30 minutes to stop the fermentation process.