I'm extracting P. aquatica and here is what I've done:
- Cooked plant material with vinegar, reduced, based with calcium hydroxide, dried, pulled with 99.9% IPA 3 times

The plan is to do FASI precipitation on the combined IPA pulls.

However, I've seen it recommended to put the IPA pulls in the freezer to let impurities insoluble in IPA settle and decant it.
My IPA has been sitting in the fridge and some white powder has settled at the bottom of the jar. It's probably calcium hydroxide, but what if some of it is DMT? It's a lose powder and not crystals. Also the IPA, which was clear at room temperature, is very cloudy after cooling.

I understand DMT is very soluble in IPA, but the colder the IPA, the less soluble it is. Is it possible that when you cool / freeze your IPA pulls, some of the DMT that was in solution at room temperature will fall out of solution?

I guess the most prudent thing to do in such cases of uncertainty would be to save the sediment just in case. But I'd rather not keep a bunch of 'collateral' jars for each extraction if it's avoidable.

I haven't specifically tried freezing IPA with DMT but... Ive tried solvents where DMT is like xylene, and DMT didnt precipitate, so I would suppose that it would def not precipitate.

Should be easy to test if anybody has some IPA and DMT at hand.

You can always save the sediment just in case indeed, and easy enough to use some ehrlich reagent or do any number of follow up tests to confirm whether its indeed not DMT.

Thanks. I guess what would help is some DMT solubility in IPA figures.

For my extraction I eventually ignored the sediment and did FASI on the IPA with the sediment. I don't think there was enough calcium hydroxide in it to worry about. I'm not worried too much about impurities as this is for oral ingestion.

I can always add a dash of ascorbic acid, which - if there is any calcium hydroxide in my product - will convert into calcium ascorbate, a great nutrient providing both calcium and vitamin C.

Although not specifically in IPA, looking at homologues we know freebase DMT is highly soluble in ethanol and only precipitates from 50% aqueous ethanol at about -18°C, rapidly redissolving with even slight warming. I can only imagine that the solubility in IPA is even higher although whether this extrapolates to IPA/water mixtures would, as endl suggests, be fairly easy to determine experimentally. I will try this out eventually.

Given that you used 99.9% IPA, it seems exceedingly unlikely that DMT would precipitate at normal domestic freezer temperatures.

The powder that has precipitated is almost certainly calcium hydroxide or calcium carbonate.