Tuesday, July 4, 2017

Two Fermentation Heat Sources Compared

I have tried using different heating methods to keep the fermentation temperature at an optimum. I like to use the oven as my fermentation vessel because I can scale up production when I want to share natto with friends. So for me, the heating source has to be strong enough to heat the inside of an oven and I do not want to manually manage the temperature.

I have tried using a yutanpo (japanese water bottle heater), pet heating pad and the oven warm setting. They all lacked the control I was looking for. 

So I bought a Single Burner Electrical Coil along with a Digital Controller Thermostat. This turned out to be the two most important pieces of equipment to give me a reliable fermentation regardless of the season or ambient temperature. I have been using this setup for more than three years. (Note: This is not the proper use of the single burner electrical coil so use at your own risk).

Single Burner Electrical Coil and Digital Controller Thermostat

I recently found a 150 watt Ceramic Infrared Heat Emitter online (plus the white socket power plug) and was curious to see if it would be powerful enough to heat the inside of an oven up to 98F (37C) needed to ferment natto. (Note: Again, this is not the proper use of the ceramic infrared heat emitter so use at your own risk)

150W Ceramic Infrared Heat Emitter, Socket with plug, and Digital Controller Thermostat

In order to test the two heating sources, I used a temperature data logger (Elitech GSP-6 Temp Logger) to follow the two heating sources. I charted this over some time measured in minutes.

Set Temp: 98F (37C)

Single burner
Max: 108F (42.4C)
Min: 95F (34.9C)
Avg: 101F (38.3C)

Ceramic Emitter
Max:  103F (39.4C)
Min: 94F (34.5C)
Avg.: 98F (36.8C)

The set temp for the digital controller thermostat was 98F (36.7C) for both runs. The ambient temp was around 80F (27C). It can be seen that the Single Burner Electrical Coil (Red line) had a higher peak temperature and it took longer to cool. This is because the particular single burner I use has a solid metal plate instead of a metal coil found in most. One disadvantage is that the dial is getting finicky and I have to jiggle it until it switches on. 

In contrast, the 150 watt Ceramic Infrared Heat Emitter had shorter On/Off cycle and had a lower max temp. It is simpler in design so there are fewer things that can break compared to the single burner. 

Both of them are great heat sources in conjunction with a digital controller thermostat. I use a glass baking pan as the fermenting vessel so the higher max temp of the single burner is not much of an issue due to the insulating properties of glass.

The 150W Ceramic Infrared Heat Emitter is a new addition so I will be using this to test it out. Moving forward, my recommendation will be for the 150 watt Ceramic Emitter. I will post any new info if my recommendation changes.

If you have any questions, please "Contact Me" instead of leaving a comment.

Natto Dad