Hemp - Crude Oil - Decarb Temp


Our current process with hemp is to extract with ethanol, filter, winterize, then decarb.

We decarb by heating to 150C, then let it rise to 170C. Keeping it at around 150C for 4 hours. Problem is that after decarb, during our short path distillation, our terpenes are coming out light blue to light green, and for our hemp (Cherry Wine) biomass, they should come out light yellow. Should we lower the temp? Should we lower the time? I’m nervous to do this because I want to make sure all the volatiles are removed, on the other hand, I don’t want to damage the terps or the cannabinoids.

Here is a picture of our terpenes from yesterday:



There’s another related thread. See the research article i posted there as well.

4 hours is an incredibly long time for decarbing especially at those temps. Note what the article says happens to the CBD content over time. There is loss, probably isomerization but they didn’t pursue it to determine where the CBD mass went.
Are you doing it under vacuum i hope?

That blue/green looks like an azulene fraction. Search on the forum here and you’ll find several discussions on azulene.


Thank you for the article reference. A great study. We are going to drop our decarb temp to 130c for 2 hours and see how the terps come out of the short path (and our distillate too of course :). Our VTA short path is a bit temperamental when it comes to decarbed material.


Exposing your extract to 150c for 4 hours is absolutely degrading your oil and negatively effecting your overall quality. 150c is acceptable without vacuum only with a quick, efficient exposure method like some thin film or spray. If youre doing the normal Decarb route with a stainless steel bucket, then 130 is the maximum temp you want to hit. get yourself an overhead stirrer so you can ensure youre not overflowing from the bubbles produced.

125 for 4 hours and good stirring will normally fully decarb and significantly devolitilize. But ideally youd do a hefty devol and only have to go single pass through your VTA for max purity and max yield. DM me if interested in that route


seems like azulene or other undesirebles. My understanding tho is terps convert to terpenoids from the short path process and are useless after. We habe thrown away liters among liters of “terp” fractions