Crockpot on High with a tea towel under it?

January 29, 2013 12:56 PM

My mother left a crockpot with a tea towel under it on the counter today before she went to work. It was on high. It was pretty hot. Am I overreacting in thinking that this is unsafe?

The crockpot has no timer, if that makes a difference at all. I'm assuming that she was going to turn it off when she got home at 4:30pm (she leaves at 8am). I don't want to bring it up with her if I'm being silly about this. Anecdotes are welcome as well.

Thanks in advance!

posted by heavenstobetsy to Home & Garden (21 answers total)

Best answer: The idea of a crockpot is that you can leave it on cooking all day while you are gone. I do it all the time.
posted by Eicats at 12:58 PM on January 29, 2013

Best answer: If you're concerned about the crockpot, then you're being silly because that's what they're for. If you're concerned about the tea towel, you're not being silly at all. Fabric is combustible. If your mother wants to protect the counter from the crockpot, she should use a heatproof trivet.
posted by Sidhedevil at 1:01 PM on January 29, 2013

Response by poster: I have no issue with the crockpot being on. But is it really cool to have a tea towel underneath it? It just seems wrong to me.
posted by heavenstobetsy at 1:01 PM on January 29, 2013

Best answer: Fabric is combustible.

If the crockpot is going to get hot enough to set a cotton or linen tea towel on fire when that tea towel is placed underneath the crockpot then the crockpot isn't safe to leave on in the first place.
posted by yoink at 1:05 PM on January 29, 2013 [11 favorites]

Best answer: Assuming a cotton tea towel, the autoignition point is 756° F (407°C).

I don't think you have much to worry about here.
posted by ook at 1:05 PM on January 29, 2013 [8 favorites]

Best answer: Cotton catches on fire at 410F (210C). The crockpot itself, let alone the external bottom of it, is not typically going to get anywhere near that.
posted by cmoj at 1:05 PM on January 29, 2013

Best answer: I probably wouldn't leave it unattended on a can of gasoline, but I (personally) wouldn't worry about leaving it on a tea towel.

Or, said another way, if your crockpot is so hot on the outside that it would cause a tea towel to ignite, I would not think it is safe to leave unattended under any circumstances.
posted by Admiral Haddock at 1:06 PM on January 29, 2013 [2 favorites]

Best answer: Oops. ook is right. You need an autoignition temperature in this case. Even less likely.
posted by cmoj at 1:06 PM on January 29, 2013

Best answer: I wouldn't do it, but I doubt it would ever be a problem. Lots of countertops and tables are combustible, and you can leave a crockpot on top of them. The only problem I see is that the tea towel could fill up the vent space under the feet of the crock pot but I think that's more of a theoretical danger than a real-life danger.
posted by mskyle at 1:06 PM on January 29, 2013

Best answer: The fire point for a cotton cloth is around 400 degrees F, which is a lot hotter than a crock pot will get under normal circumstances. The exterior of a crockpot shouldn't exceed about 300 F and will probably be a lot closer to 200-something assuming it's full of water which will limit the temp to 212 F.
posted by GuyZero at 1:06 PM on January 29, 2013

Response by poster: I don't think there are any vents underneath or anything.

Thanks everyone, this is useful information. I may mention the trivet as opposed to tea towel, but otherwise, it seems fine. Thanks!
posted by heavenstobetsy at 1:09 PM on January 29, 2013

Best answer: If the crockpot is full of water (or broth, or gravy, or anything like that) it acts as a temperature mediator. If it gets hotter than 100C then water starts boiling off and keeps it there. Once all the water is gone, only then can it get hotter.
posted by Chocolate Pickle at 1:09 PM on January 29, 2013

Best answer: The tea towel might not be cotton, though. I have a few made of synthetics, which are much more flammable. Probably better not use the towel i'd say.
posted by windykites at 1:26 PM on January 29, 2013

Best answer: As long as there was space between the towel and the bottom of the pot, I'd say it's fine --- i.e., if the pot has at least some sort of stubby legs to raise it above contact with the towel.
posted by easily confused at 1:29 PM on January 29, 2013

Best answer: A good idea.... if it fits, set the crock pot on the stove while you're gone.
posted by HuronBob at 1:36 PM on January 29, 2013 [2 favorites]

Best answer: I think this is a very bad practice.

Crockpots have a thermostat which makes and breaks the circuit to the heating element many times in the course of a cooking a single typical meal, and each time the circuit breaks, there's a little spark between the contacts which can cause pits and mounds to grow on the contact surfaces, which can in turn over a long period of time cause the contacts-- very rarely-- to weld together and cause overheating, as happened to me once with an electric frying pan.
posted by jamjam at 1:57 PM on January 29, 2013 [1 favorite]

jamjam: "… cause the contacts … to weld together and cause overheating"

Which is why crock pots - which, unlike electric frying pans, are designed to run for long periods unattended - include an additional thermal cut out (typically 250°F or so) in series with the normal thermostat / simmerstat.

Seriously, these things are designed to only just be able to boil watery liquid at best - the element etc. is not really capable of getting too much hotter than that. And, if through a chance series of failures it does (e.g. thermostat sticks AND element shorts internally), the thermal cutout(s) operate at just above boiling.
posted by Pinback at 2:28 PM on January 29, 2013 [1 favorite]

If there was an electrical fire caused by the crockpot, then yes, the tea towel would burn. And so would the rest of the kitchen. Barring that, nbd.
posted by elizardbits at 2:55 PM on January 29, 2013

I imagine she's doing it to catch any spills. If it really concerns you, try getting her to put something like a pizza pan under it instead of the towel.
posted by Chocolate Pickle at 4:42 PM on January 29, 2013

If the crockpot is going to get hot enough to set a cotton or linen tea towel on fire when that tea towel is placed underneath the crockpot then the crockpot isn't safe to leave on in the first place.

Which is why crock pots - which, unlike electric frying pans, are designed to run for long periods unattended - include an additional thermal cut out (typically 250°F or so) in series with the normal thermostat / simmerstat.

Sometimes appliances fail; if the crockpot's failure takes the form of "Run too hot until unplugged" then a trivet will save your ass whereas a tea towel will just make nice tinder.

Moral: buy your mum a trivet.
posted by sebastienbailard at 5:23 PM on January 29, 2013 [1 favorite]

It is possible for a crockpot to cause cracks/damage to Corian (and even granite/quartz) countertops; not that it gets super-hot and scorches, but the slow addition of heat all day means that when you take the pot away there's thermal stress between the warm area underneath (mine's not too hot to touch, but hotter than"warm") and the cool area elsewhere, or something like that.

Anyway, whether that's why or not, there's probably a reason why she likes putting a tea towel underneath, but there are definitely less-flammable things that she could use instead. The crockpot is not supposed to get hot enough to cause damage, and she's surely done it many times before with no problem - but things do malfunction, and suddenly overheating is a common failure mode in slow cookers.
posted by aimedwander at 8:58 PM on January 29, 2013