Help creating an off grid crock pot

We eat a lot of dried beans which we cook in an electric crock pot (takes 4-8 hours depending on bean).  

I was thinking of creating something similar to the Rock Pot Kit below.  Looks like we could make one  (our preferred method over buying new).

Basically an insulated cooking vessel that you add a heated stone into + your preheated food to let slow cook through the day.



Has anyone tried this with a Wonder Bag, by adding an additional heated stone?  If so, what would be the best material for the stone? I have some old round steel weights (?) or maybe a pizza stone (?) or would a fire brick be best (?)  I may also invest in the stone provided by Rock Pot.

I wonder if "haybox cooker" or variations of that would give some more ideas.  I'll see if I can find the thread I'm thinking about.

Another idea is an electric pressure cooker.  These are super insulated.  Bring it up to pressure, then turn it off without opening.   Probably take the same electricity to cook as a slow cooker, but it wouldn't be spread throughout the day.

https://permies.com/t/8127/Haybox-Cooking-Thermal-Cooker-Box

This might have some ideas

Beans really need to be actively boiled for several minutes to get rid of the lectins. I don't think I'd trust just using a hot stone to bring them up to temperature and hold it there long enough to do that job.

I usually soak mine overnight, then bring to the boil on the stove for about five minutes, then transfer to a haybox for eight hours.

Using a wood cook stove to cook beans  eliminates a lot of paraphernalia, any pot with a lid will do, and the heat is nearly free. Been cooking beans this way for 40 years.
There might be some truth in that old saying that "the key to our future lies in the past"

If you can , dig a hole, build a fire to fill the hole, bury the bean pot in the coals, add more fuel on top let it burnto coals put sod bak on top come back in 24 hrs, beans will be done, Bean hole beans   google it

Another source of inspiration could be the Easy Bake Coffin. It's an electric slow cooker, like a crockpot, with some improvements. It's a lot bigger, sized and shaped like a coffin, hence the name. While it's heating, I believe it uses about the same power as a crockpot. But it saves a lot of power because it's heavily insulated and has a thermostat. A crockpot heats until you shut it off. The EBC heats until it's hot, then shuts off until the temp gets below the setpoint. If you build something similar but smaller, pre-boil the beans and put them in hot, this could do what you want on low enough power to run on a battery. Of course you could also optimize to use no power, but then you've got yourself a haybox cooker, which was already mentioned above.

Burra Maluca wrote:Beans really need to be actively boiled for several minutes to get rid of the lectins. I don't think I'd trust just using a hot stone to bring them up to temperature and hold it there long enough to do that job.

I usually soak mine overnight, then bring to the boil on the stove for about five minutes, then transfer to a haybox for eight hours.

Thanks so much Burra, Yes, I would be boiling the beans first.  I built a hay box yesterday from a styrofoam cooler lined with wool, and hemp fiber I had on hand.  Box more practical than the sewn bag. Wonder if I should use the metal pot I boil them in or transfer them to a preheated dutch oven type vessel.

Scott Leonard wrote:If you can , dig a hole, build a fire to fill the hole, bury the bean pot in the coals, add more fuel on top let it burnto coals put sod bak on top come back in 24 hrs, beans will be done, Bean hole beans   google it

Love this, I remember my grandfather baked his potatoes this way. Will try this when our burn ban lifts.

r ranson wrote:https://permies.com/t/8127/Haybox-Cooking-Thermal-Cooker-Box

This might have some ideas

Perfect, this will have all the info I need. Thank you so much.

I just use the same pot as I boîl the beans in.

As someone mentioned, Easy  
Bake Coffin is the best idea. I've been toying with the idea of using solar panel + battery to power a crock pot (small 80 -120 watts ) I didn't know the Easy Bake Coffin idea was around till just now, but my idea was to enclose the crock pot within a wooden cube first (plywood with hole for the power cord and a top hole for steam and maybe a thermometer) . Then install a fishtank like( or other thermostatic) switch that will keep the crock pot within ?5 degrees of cooking range ?180-185 and prevent pot from overheating and damaging element. Next, using foam board/radiant barrier cut panels, continue to add onto the existing plywood box to about 4-5 layers. With 1/2 inch material that should give r value around 5-6. Goal is to get to the point where only a fraction of the OEM watts are actually needed (ie 20-25) to maintain cooking temperature. Then your batt only needs to run the power 25 percent duty cycle or 15 min of each hour and it's same as using the OEM 80 watts at full duty. Theoretically, if you have a single 100 watt panel on a cloudy day, it could cook a whole lot of beans and not drain out the battery. The physics/thermodynamics says it will work, since by adding insulation, you are approaching IDEAL conditions(heat loss minimization) for the formula for water heating and the cooling curve for a liquid(namely water). Next will be micro refrigeration, using small cube mini fridge. Crazy and zany but these ideas may be useful for off gridders( where every watt counts) and in an extended grid down situation

For simplicity and cost, the CanCooker is a good option

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