Heat source for fermentation

[byron.hawkins]

I'm looking for a small and efficient heat source so that I can use a camping cooler for making yogurt and other lacto-fermented stuff. In my last apartment I had a gas oven that maintained 105°F all by itself, because of the pilot light :-) But I just moved, and the appliances here are electric.

For now I am using a cooler with a light bulb inside, but of course that is not cost effective. Can anyone recommend some kind of cheap device that I could put in the cooler to keep it around 105°F? Thanks for your help.


Byron

[Tim Hall]

Light bulb is probably the best, cheapest option really. I've used all kinds of things, like reptile heat cords, heating pads, etc. In reality anything that generates the amount of wattage you need is going to use about the same amount of energy. Incandescent bulbs are really inefficient in this way, and work just as well as heating elements as they do light sources. There's really no difference between the tungsten filament in a bulb and the heating element (assuming electric) in your oven.

You might play with the wattage of your bulb. If the cooler isn't too big and seals well, you might be able to get away with as little as 30W.

The system I use is probably way overkill for most people, and it's expensive initially. I use a thermostatically controlled 2-stage relay, one for cooling, one for heating. It's probably more energy efficient than just leaving something turned on, but the control unit costs around $100. For yogurt I only use the heating stage (and you can get cheaper 1-stage units) - plug a 100W bulb into it and put that and the milk inside my oven or an ice chest. For more temp-critical ferments (koji, beer, tempeh, mushrooms) I plug a chest freezer into the cooling side, and drop the light bulb in the freezer to keep it within 2 degrees of the desired ambient temperature.

[Wind]

Can't find the link right now, but there was a comment about making yogurt i non-electric yougurt-maker from eBay. It was said that this is essentially kind of styrofoal/plastic shell, you put your culture in a fitting glass jar, heat it to 110 degree, close it, and put inside this thermos-like device. In 10-12 hrs yogurt is ready.

I had yogurt maker from garage sale for $5, worked like charm.

[Tibor]

Tim, I'm trying to understand how your 2- stage works when you are using the freezer on the cooling side of your controller. What's the difference between the sides of your 2-stage? I want to start learning about mushroom cultivation and my tempeh incubator is too small .I want to use a small freezer I have, so can you explain to a tech challenged guy how it works? And which brand of unit did you buy?

And while you are at it, I can't figure out(and I've tried numerous times) how to use the quote highlighted function for just a sentence or two.

thanks :)

[Tim Hall]

Tibor, depending on the application I may not actually use the cooling, or heating, or I may be using both in conjunction to keep tight control over the temp. The controller I have is called a "two stage" controller because it has two relays inside, two plugs for two devices, and I can set a max low temp and a max high temp.

As an example, let's say I want to keep some beer right around 68F, and let's say my ambient temp is in the high 70's (actually in the mid 80's right now). I'll plug the freezer into one stage and set that for say 69F, then plug a light bulb into the other and set that for 65F. The thing about the freezer is it will continue to draw in heat for a time even after the compressor stops, so it can potentially drop the temp slightly below what that yeast likes. But if that happens (temp goes below 65) the light bulb will switch on and briefly warm things back up a degree or two. I sometimes have to play with the temperature ranges, but ultimately I can get an average temperature that hovers right around 1-2 degrees of my target without the devices having to switch on and off a lot (short cycling).

Even though there's a little overlap with energy usage with this method, it's still very efficient, and requires little energy to maintain that temp range inside a chest freezer where the hot/cold doesn't leak out like an upright fridge with a door.

I actually have a preliminary design (which is probably way overkill for easy mushrooms like oyster mushrooms) in mind specifically for mushroom farming - if you can kinda follow this: 1) remove the lid to the chest freezer, 2) build a "frame" out of 2x6's that attaches to the perimeter of the top of the chest freezer, kinda like adding a 6" lip to the top of the freezer, 3) this frame then houses a microcontroller that will moniter/control temp, a computer fan for fresh air exchange (either on a timer or set to a CO2 sensor), and maybe a humidistat that will control a humidifier, 4) re-attach the freezer lid to the frame, the freezer is now ~6" (nominal) taller than before.

* For quotes, I just manually delete the text I don't want inside the BBcode. Look up BBcode.

[Tim Hall]

Wow, these have gotten more expensive! This is what I have...keep in mind it may require some wiring (adding plugs.) Also make sure you're getting one for 120VAC and not a low-voltage DC model.

http://www.etcsupply.com/ranco-etc24100 ... p-109.html

Also Johnson Controls makes similar controllers, and there are probably other manufacturers out there now making similar products.

Tibor, the only reason I have this two-stage setup is because I use it for so many different things over a wide range of temps. If you plan on working with things on just the cool side or the warm side, you may be able to get away with a single stage controller. Some of my ferments want to go into the low 50's, some want to be in the mid 80's.

But let's say you want to do something in the 80's and your ambient/room temp is always below this, all you would need is some kind of insulated inclosure, a heat source, and a single-stage controller wired for heating (switches on at a minimum temp.)

If I ever get around to building some of this more advanced stuff, I'll maybe post a how-to with illustrations and photos.

[Tim Hall]

This one is totally prewired, and ready to go out of the box...

http://www.etcsupply.com/ranco-etc21100 ... p-110.html

It's just not NEMA rated for moist/wet environment, which should not be a problem, because the controller stays outside your incubator.

[Tibor]

Wow Tim, thanks so much for taking the time. I appreciate it. I get it now .I'll check out those links and see which way I go. I wired my present incubator so I am capable of some stuff. Thanks.

BTW, I did make viable potent spore. After all those fails, it was very exciting. Gem culture spore was the ticket. I'm doing a bit more experimentation before I put up a post.

[Tim Hall]

Tibor, I was talking with some friends who've suggested I get into doing a small-scale commercial mushroom production. Here's a device that will override the controls on a window ac unit. I may be converting the storage building in my backyard into a climate-controlled grow room at some point.

http://www.storeitcold.com/howitworks.html

[Tibor]

The reason I stay so tuned to this forum is to learn, and to get inspired and also to inspire others. How can you possibly beat an almost completely home made tempeh reuben ,with a pickle and a glass of kombucha :) . I do use a lot of mushrooms in my tempeh recipes which leads me to want to learn how to grow some. Thanks for the info, Tim.