Decarbing gone wild

I can’t for the life of me decarb without getting caramelization and burnt material. I’ve used hotplates, waterbaths and an overhead stirrer. I had best results with the water bath, but it took forever.

I also seem to lose way more than i expected, more than a third when I’m done. Staying at 115c. Last batch started with a bit more than 2.5 liters ended with 1.75 liters. Took 7 hours with magstirrer, stirred with the overhead, still caramelized the edges.

Are you decarbing under a full vacuum?

I think that’s gonna change everything for you

If you can’t use vacuum your gonna have to blow inert gas over it

Btw you lose a good bit, but I don’t know the exact amounts

I believe someone that knows for sure chiming in now or they will soon!

Lost weight during the decarb is pretty normal. Loss can be in the form of water, terpenes, and loss of the carboxyl group. All these things have mass and speak for the the weight difference you’ve observed. What method are you using to isolate your bulk thc? It sounds like removal of plant sugars and inert gas may help.


A lot of crude on the market still has solvent or even water in it, so that could account for the loss. Decarboxylation does release CO2, leaving you with theoretically 87.7% of the starting weight (if you had pure THCa)

It shouldn’t take 7 hours at 115C. I decarb under vacuum, and I don’t get that “carmelized” layer left behind


How long should I under a full vac? If you didn’t have means to get vac oven should I switch my chamber to stainless steel vessel, then could I set on magnetic stirrer hot plate to hit temps, or is the stirrer not needed… Just trying to figure out easier ways I don’t have the means to set up the old argon tank at the moment, I could see me taking it from the shop lol

You could inflate a balloon with argon and attach it to your decarb setup

Edit: This is a photo from google, not mine


If you stir, it will happen much faster, but it will also bubble up a lot more heavily, as only so much gas can escape through the orifices at once. If the flask is very full, I don’t stir at all and increase temperature very slowly until the bubbling ceased (140-160C). How long the process takes actually seems to vary based on the pump, but usually 30 min - 1 hour in the same round bottom flask I distill from. Higher CFM pump can rip the CO2 out much faster, which means a smaller “muffin” in the flask. If it starts boiling over, bleed a bit of air back into the system (if no inert gas is present)

Wait, what? Where does the CO2 go?

Ideally this would be good to decarb small amounts of thca isolate. In a much larger format one could place a second needle into the septa to allow gas to flow from the balloon, through the flask, and out into the air. If you use a small Guage needle the gas flow will be very slow and controlled. This is a viable option for someone without gas and vacuum mantifolds. It is often practiced in educational settings where there are a lot of students learning air and water free chemistry.


I’ve been using etho for the extraction, this time it’s been with kief at room temp.

I think I’m gonna try and decarb in the bf under vac. The entire run took 7 hours, was only at 115 at the end when it stopped bubbling. It was stuck at 78c for the most part, so i think it was boiling off solvent. I decarbed in a 5 liter beaker. Was also thinking about maybe trying a sidearm flask on the magstirrer.

So just to be clear, you setup your glassware and collect your heads while doing this? I thought decarbing in the bf muffins the system? I’m not sure how I’m doing this.

Yeah, solvent and terps will collect here. I like to use the roto’s pump to handle this job, so I don’t beat up the Edwards/Welch. Once decarb is coming to a close, I switch to the high vac pump.

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Hmmmm, yeah if i can decarb in the bf as I’m collection volatiles that would be a game changer.

You should be decarbing a little hotter, for a lot less time. 78c is going to take forever. I’ve used a big steel pot, a jacketed reactor, a convection oven, and a bunch of other janky methods. I’ve never had a problem decarbing in atmospheric conditions, and am not a fan of doing it in the bf for fear of the brown hash :volcano:


I had it set to 121c on a hotplate in. 5l beaker. It was just stuck at 78c forever. I might have to go back to pot and induction plate. Believe me, i don’t want to be doing it that long. Even with me constantly stirring with a spatula its been caramelizing. The new hotplate had some issues, so i used the overhead stirrer i just got but the paddles are to small. I think my stirbar is getting degaused, cause it’s not performing like it did. So I’m gonna try decarbing a smaller batch in the bf today. See what happens. My mantle also always overheats to fast or slow as fuck, so i’m getting burned material which i think is inhibiting the stirbar from spinning. So I’ve just not gotten anything dialed in yet… i will get there though.

Is your vessel open or closed? Do you notice a large amount of reflux?

Hmm are you getting an accurate temp reading then? Do you have second way of checking… Also I know my method no where near as accurate and I will only have this problem getting over temp… Way over… You said stuck on 78c , might double check to verify…

I’m probably wrong but sometimes in theses situations it can be the smallest thing and you can get the answers where you least expect it

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The decarbing is done in an open vessel. This time on my brand new scilogex mag stirrer. I was having issues with the stirbars getting stuck mid spin, so i opted to use the overhead stirrer. I set the mag stirrer to 121c, when it hit 78c it stopped. I verified with a second thermometer which gave similar readings, 1-2 degrees higher. I thought it might be boiling off solvent and after a couple of hours it started going up. The overhead stirrer was set very high with no muffin occurring.

Edit: im gonna try the pot and hotplate again, maybe put the beaker on a griddle. I’ve been trying to go as slow as i can, but it’s still taking to long and caramelizing whichever combo of things i try.

Used hotplate with the overhead stirrer, got temp up to 140 then down to 112 to finish in 2h 45 min. That seemed to solve my situation.

I’ve also been priming my new Frankenstein setup half lab soc silvered head for volatiles and half summit laminar path. Both heads have their own dewar cold trap run by one pump each. So i don’t have to break vacuum for the first time ever. System was running at 198 micron with the 12 cfm volatile pump just now. Gonna run the decarbed material. Waiting for the glassware to preheat. Then it’s on.

Ethanol boils at 78C.
suggesting to me that “stuck” actually indicates “boiling off solvent”.