I also want to know if I can put a rock in an Instant Pot just for fun

June 27, 2023 2:42 PM

The directions say you can't put a Lucky Iron Fish in the Instant Pot, but it doesn't say why. Is it likely because they just didn't test it? Or is it because something bad will happen?

Clearly you can put racks, trivets, pans, etc. in the Instant Pot with no ill effect. Why not an iron ingot? The only thing I can think is that it might crack, somehow.

Mostly we will use the thing for infused water. But it would be good to be able to use it for soup the usual way we cook it.

posted by blnkfrnk to Food & Drink (8 answers total)

Best answer: There's a useful answer on amazon. It looks like you only get the benefits of the iron fish if you are boiling water, and not if you're pressure cooking. They suggest if you want to pressure cook with fortified water, you can boil the fish in the water first (in the IP or elsewhere) and then use that water for pressure cooking.
posted by moonmilk at 2:51 PM on June 27, 2023 [1 favorite]

Best answer: This makes no sense. The temperature in a pressure cooker can actually get hotter than boiling at atmospheric pressure. As long as you are pressure cooking for 10 minutes or longer the iron content should be the same, or a little higher.
posted by H21 at 3:21 PM on June 27, 2023 [3 favorites]

Best answer: My bet is they think the cook time won't be long enough for a lot of recipes. Reading the background information, you're basically boiling a lump of iron in acid so that you get some dissolved iron salts at the end of it, and I don't see how pressure would have a significant effect on that. Maybe it could break the fish, but assuming the fish is supposed to rattle around in the bottom of a pan of boiling water and put up with sudden temperature shocks that would seem unlikely. That's all conjecture, though.

Their comment doesn't say you can't put it in the Instant Pot, only that you shouldn't use it in a pressure cooker (and they do say that the simmer setting of a pot would be fine). So perhaps, if you have the time to do it, you can simmer the fish in the pot for a while on simmer, remove it and then switch to pressure cooking (which would go a little faster because you've basically preheated everything at that point)?
posted by How much is that froggie in the window at 3:24 PM on June 27, 2023

Best answer: I also think the iron delivery should be fine.

I wonder if the idea is the fish will damage the nonstick coating of the pot (I think it would, but maybe not in a way that bothers you).
posted by SaltySalticid at 3:28 PM on June 27, 2023 [1 favorite]

Best answer: It's at least plausible they're concerned that, under pressure, iron delivery could be too high, not too low.
posted by kickingtheground at 3:58 PM on June 27, 2023 [2 favorites]

Best answer: Their site says that "the product should not be used in a pressurized environment. You may cook with it in a pressure cooker if you are only using the boil or simmer setting." I would interpret that to mean that they are concerned that there might be a small bubble of air trapped inside the fish that might cause cracking if placed under pressure. I don't think the amount of iron is going to be hugely different with pressure cooking versus boiling (even if the pressure cooking is shorter, with the heating up and cooling down time, the time around and above boiling is always going to exceed their minimum of ten minutes).

It's also possible that it's just CYA and the real risk is near zero.
posted by ssg at 4:48 PM on June 27, 2023 [9 favorites]

Best answer: Diffusion vs. temp and pressure is complicated, so ssg is almost certainly correct (or, more accurately, correct enough that you'd need to do serious testing to make a better determination, IMO).
posted by aramaic at 6:01 PM on June 27, 2023 [2 favorites]

Best answer: I would interpret that to mean that they are concerned that there might be a small bubble of air trapped inside the fish that might cause cracking if placed under pressure.

...which brings me to the post title, which was probably facetious but:

NEVER BOIL ROCKS. They often do have bubbles inside and can explode dangerously. Well-meaning aquarium keepers do this to sanitize rocks sometimes and sometimes it goes horribly wrong.

Also most Instant Pots do not have non-stick coating.
posted by mmoncur at 8:15 PM on June 27, 2023 [14 favorites]