The Fireless Cooker That Feeds

[ajot]

Little nitpick: the title is "The Fireless Cooker that Feeds Low-tech Magazine", as in "this is the fireless cooker we use".

[tyleo]

Thanks for this. I was quite confused by the title. It appears as "The Fireless Cooker That Feeds" for me. I thought, "Isn't any sort of cooker supposed to feed?"

[cedricd]

Explaining this just to make sure I get it.

When we cook we're bringing up food to a certain temp, then maintaining it at that temp till it's done cooking. If we could perfectly insulate it, then it could hold that temp as long as we want without being on the fire. So the only energy input is getting it hot -- after that it's cooking on its own.

So this is trying to approximate that by insulating the pot.

I always sort of assumed that there's a lot of heat 'loss' from food itself heating up -- as in most the cook time is getting the food up to the temp (i.e. when cooking a steak), not waiting for it to cook at the temp. But I suppose that for certain grains and stews and things that thinking is wrong.

[falcolas]

You're not wrong - once the food is at the right temperature, it's done. You can hold food at the "right" temperature for a long time, but if you go above it, it'll over-cook.

There's a few ways to heat food up, the most common of which is to heat the vessel to well above the right temperature and wait for the food to come up to the right temperature. The cooker linked takes advantage of this method since it is fine if the vessel comes down in temperature a little bit, so long as it doesn't get below the food's "done" temperature. You still have to be vigilant about the temperature of the food, to ensure it's not overcooked.

The less common method is to heat the vessel (often water) up to the right temperature, and let the food come to equilibrium. This is basically sous-vide, and would not work with the linked method, since the temperature of water can't go down. You might be able to fudge things a bit by over-heating the water a bit, but then you risk overcooking the food.

[brudgers]

A longer article that was cited, https://www.lowtechmagazine.com/2014/07/cooking-pot-insulati...

[finiteseries]

Everything related to heat transfer is still relevant and very, very interesting, but I love how dated the assumption of non renewable energy is now in that method of calculating thermal efficiency.

Who cares if the perfect turbine could only ever convert 59% of the wind power through it!

[blacksmith_tb]

It's a very large teapot cosy, in other words. Seems reasonable, though obviously you still need some way to bring the pot up to temp (for that cast iron, induction would be efficient if not low-tech).

[RankingMember]

Yeah, when I think of a cooker, I think of something that heats something up, not just keeps it going.

The stove with one burner dropped down [1] seems more practical, not requiring a separate device/extra step.

[1] https://krisdedecker.typepad.com/.a/6a00e0099229e8883301a3fd...

[druadh]

They do mention that in the article "doubles the efficiency of any cooking device because it shortens the time on the fire"

[ziggus]

There's a few commercial versions of this idea that combine some sort of insulation with a vacuum container, which increases the efficiency.

https://www.cabelas.com/shop/en/thermos-cook-and-carry-syste...

[jerrycruncher]

There was also an infomercial[1] for a product called "AirCore" in the US a couple decades ago for something similar.

[1] https://www.youtube.com/watch?v=SIIWBvgyvmI

[AmosLightnin]

When cooking, the rate of heat needed to maintain the same temperature is exactly the rate at which the food is cooling. So heating up a pot and insulating it is roughly equivalent to heating up a pot and continually heating it to maintain the same temperature. If we changed the culture of cooking to recognize this, we could save a lot of energy.

[falcolas]

The pot in this "cooker" is dropping in temperature. Slowly but surely, since no insulation method is perfect against heat transfer.

[cultofmetatron]

And this is why the instant pot is such a good value. It's very insulated and incredibly efficient

[GeekyBear]

I have a different brand, but I use my electric pressure cooker many times a week. It's a great time saver for cooking real food from scratch.

[jack_riminton]

As well as easy-to-use, safe and consistent

[nllewellyn]

We used to cook up a stew or a joint in a casserole dish with a lid (like a dutch oven), and put it in a haybox for the day so we had a hot hearty meal at the end of a day outdoors.

https://en.m.wikipedia.org/wiki/Dutch_oven https://en.wikipedia.org/wiki/Haybox

But I've just found this and it looks excellent! https://en.m.wikipedia.org/wiki/Thermal_cooking

[falcolas]

TL;DR: It's just a good amount of insulation around a vessel (like a crockpot) that's been heated up in some other way.

[elitepleb]

A great way to cook rice when electronic assistance is unavailable.

[aitchnyu]

Styrofoam is stable upto 79 C / 175 F. But is it completely safe, especially from offgassing?

[turtlebits]

These have existed for years in Asia. Just search for “thermal cooker”.

[foobarian]

What problem is this trying to solve exactly

[aspyct]

Cooking when/where energy is scarce. Very useful to save on fuel while camping, for example. Also, I suppose, next time the electric grid is down and you want to cook on battery.

[oh_sigh]

A lot of people out in the country don't actually have a gas line to their house, and cook using bottled gas. I lived in a situation like that at one point - the cost of the gas saved by the device wasn't really important to me, but it was the burden of making a half day trip to the city to replace the bottle that pushed me to conserve gas.

[fnord77]

so, styrofoam is not technology?