Hi Canyon -- I took a lot of chemistry in college and thought it was really interesting, but I was by no means a chem wiz (and that was back before my beard turned gray
), but what the hell, I'll take a whack at this. (I already caught a dumb mistake in the noodling below. There may be more...)
I calculate about 12% weight loss from decarboxylation too, yeah. I think that the weight loss from just the decarb process alone would be difficult to measure, though, since you'd also have low-molecular-weight organic molecules (e.g. terpenes) off-gassing and water evaporating and God only knows what other kinds of reactions going on.
But maybe if you just monitored the total weight of the sample over time you could see when the weight stops
changing and that might be useful?
I would guess that the weight would drop rapidly at first and then more slowly, so it could be hard to know when to say "when," buy maybe you could just set an arbitrary limit, saying "It's done when the weight is changing by less than 1% in five minutes," or something like that?
Hypothetically, a 500-gram sample that's 15% THCA would have 75 grams of THCA.
That 75 grams of THCA would drop to about 66 grams after being totally decarboylated, for a loss of 9 grams.
The 500-gram sample might loose another 50 grams of H2O (10%)(??) and maybe 2 grams(??) of terpenes and other small organic molecules to drop a total of 9 + 50 + 2 = 61 grams to 439 grams in this wild-guess scenario.
And weighing the sample every 5 minutes you might see that the weight drops the most in the first 30 minutes, and after that the rate of weight loss slows until from 85 to 90 minutes it only drops 5 grams (1%) of the original weight, so you make that the stopping point and send that sample to the lab?
That might be an effective way to monitor, because even though you don't know exactly what you're measuring, you still know when the your sample has stopped losing significant amounts of weight.
The summer harvest from the little dwarf in the flower pot out on my deck is drying in the corner right now. Maybe I could give this a try just for funzies...