I was attempting a 48-hour infusion at 98-100 degrees. After about 13 hours, I noticed a lot of steam coming from the water. I used a thermometer to check the temperature, and it was a little over 150 degrees. Given the high temperature for that duration, I don’t think I can trust that the properties of the oils and herbs haven't degraded.
How long and at what temperature do you do your infusions?
Meh. If out doesn't smell burnt and you don't think water got
into the oil I would use it.
At the end of the day can you confirm the properties of your oils/herb infusion doing:
the cold infusion method?
double boiler on the stove?
Instapot?
Infusing difference for any particular lengths of time?
differences between freshness of oils and herbs?
It's all guesswork without scientific equipment. I remember reading a passing comment on a cosmetic science FB post, that infusions at home aren't done properly in general (unfortunately, no further details were given... but I assume that it either had to do with contamination or potency or both.)
So don't waste the oil. At the very least use it as makeup remember or on your feet or something, but I'd just use it in my hair and be more mindful in the next batch.
I either use cold infusion or if I use warm infusion I do a double boiler. For the double boiler, I'll boil a pot of water then reduce the burner to the lowest setting possible. Then I'll put my herbs mix into a stainless steel bowl bigger than the pot so that the bottom of the bowl is getting heated by the water/steam. You want it to steam heat the bowl not boil from bottom. Boiling from the bottom would turn it into a bain marie which is too much heat (as you pointed out).
I don't know what temperature this results in, but I leave it on the stove for about 8 hours with this heat.
When I make emulation, I use a heat and hold method for my oils and water mixtures. Each are held at 80C (176F) for 20 min. Supposedly, this helps to kill micobs and the like. I'm not sure if the temperature you mentioned was C or F, so I put this here as some sort of gauge.