Just looking for a consensus opinion regarding the optimum agitation time when performing cryogenic extraction using Ethanol as the solvent?
I have a C-40 centrifuge (40lbs of Biomass per cycle) and using -40 degree chilled ethanol.
I started out erring on the side of caution in order to ensure I was able to extract as many cannabinoids as possible, around 6.5-7 minutes of agitation. I’ve gotten feedback from a couple of people in the distillation field that this is overkill and may have contributed to why I’ve had a slight sugar issue in the final distillate. I have no problem shortening the agitation time, just hate to think that I’m leaving good cannabinoids in the biomass!
Any advice would be much appreciated
There’s a whole lot of variables to unpack here, but the real answer is going to be testing testing and more testing to determine your answer.
First of all, you aren’t going to get 100% of your cannabinoids in a reasonable time/cost-benefit analysis. You should be aiming for about 90% extraction efficiency and still be economically viable.
The amount of time will be longer the higher TAC % your input biomass is.
How are you prepping your biomass for extraction? IMO freezing the biomass first pulls out a lot of moisture and reduces the likelihood of water solubles (sugars and phytos) as well as reduces the speed your alcohol gets deproofed.
What extraction solvent are you using? Is your centrifuge jacketed? Is ethanol at -40 going in or coming out?
Admittedly, the majority of the biomass I had available at the time we got things set up was kind of a mishmash of material from several different sources of varying ages and although in general it was dry, there were a couple bags with a little moisture in them which to your point could have allowed any sugars and phytos to be pulled out during extraction.
The centrifuge is jacketed and the ethanol is -40 going in, my concern is that currently there are no probes on the chilling vessels that tell me the real time temp of the ethanol/miscella once the first extraction/filtration run has finished so it is difficult to know how long to wait until the ethanol is back down to -40 to run another bag. I’m currently working on this with an equipment supplier. All we have to go on currently is the temperature of the actual chiller but I imagine the solvent would warm up by a few degrees as it passes into the centrifuge and filtration skid.
Going forward, the biomass will be much more consistent which will provide a better opportunity to test it before and after extraction, but I like the idea of freezing it to prevent any water soluble compounds from getting pulled out.
Another important factor is the proof of your ethanol. If it’s any lower then 195 then you are definitely going to be seeing the sugars come out of your biomass. I agree with @greenbuggy that you should be shooting for ~90% cannabinoids and that the colder you can get the actual biomass prior to extraction the better for your proof. If you keep the biomass cold enough then you can maintain your solvent at ~-40°C for however many bags you are trying to run. As far as the actual agitation time goes, once you’re sure that you have a good proof on your solvent and everything is the right temp, we hardly ever run longer than a 5min agitation cycle on our 60lb centrifuge. 6.5 - 7 will almost certainly be overkill for a 40lb.
There is nothing “optimal” about pretending your centrifuge is a washing machine capable of actual agitation.
It’s not. Especially so if it was made in China.
Yes, the oem programmed the silly thing to spin slowly in one direction, then slow down and spin slowly in the other direction, but that action doesn’t come close to “agitation” and given the massive (very heavy) rotors China uses is better suited for burning out motors than washing out cannabinoids.
Edit: missed this part…
Western States understands how to build a centrifuge, so you’ve got a decent platform…even if the folks they built it for think it should be run like a clothes washer…
Thanks so much for the advice, definitely helps to reinforce a lot of the key concepts that I’m trying to get in line with while trying to improve the efficiency and quality of the extraction. We’re using 200 proof ethanol btw so that’s reassuring also.
Really loving this forum so far and all of the friendly and helpful discussion!
Your ethanol picks up water quickly. If you’re not monitoring the proof of your solvent, it can change on you and radically alter your extraction efficiency.
No worries always happy to help! Also @cyclopath is % correct. You should be proofing your ethanol before you use it for every run. Especially as your not sure about the material your working with you can run into headaches before you know it with poorly proofed solvent! Keep dialing it in and don’t forget to let us know how it’s going as you process more!
Sorry, youre totally right. I forgot to consider how the moisture in the BM would lower the proof of the ethanol from run to run. I have to get an ethanol tester. Any particular brand or unit you recommend or just a general hydrometer?
I love the SRI units, so affordable but if one doesn’t have a pretty good understanding of method development and analytical principles it can be difficult to maintain accuracy. I’ve had a lot of clients have serious issues with manual injection and prep discrepancies.
right. We’re in the process of getting that set up to better serve us moving forward. Thanks!