Q: Do you prefer warm ethanol rather than cold?
RVL: No, no. It has to be, in my opinion, -40 degrees Fahrenheit, that’s kind of the sweet spot. What happens when you extract warm is you pull sugars, because there’s still a little bit of water in it. It’s exactly like table sugar, when you go to recover your solvent and you heat it up, it caramelizes; it literally turns to caramel inside of the AutoVap. That’s called fouling. It will foul the tubes, which makes it harder for the stainless to transmit heat into the solution and eventually will clog the system. Most people see the effects of warm ethanol extraction when they go into the DR-10. I have seen baseball-sized clumps of sugars forming there. If you feed these sugars into a wiped film, which runs at much higher temps, it will foul within hours.
Q: Does it ruin the machine or do you just have to clean it out?
RVL: It doesn’t ruin it, but you have to break it down and clean it and it’s very time-consuming, especially when you go into wiped film distillation. It’s nearly impossible to distill sugar-heavy oil inside of that unit; it fouls very quickly because of the temperatures it’s running. It takes at least a full day to break down and clean the equipment, and subsequently dry it of water to achieve a vacuum deep enough to distill cannabinoids again.
Q: When you get something that cold, does the machine itself get that cold or do you have to have the whole facility that cold? How do people work with that?
RVL: Just the equipment will get that cold. A lot of our tanks are built with a fluid jacket and then an insulation jacket around them. We typically have one really big low-temperature chiller controlling the facility, so that’s applying a glycol mixture at -45 degrees or -50 degrees Fahrenheit, which does the job of cooling down all the solvent inside the machine.