From my experience, a third pass is unnecessary. The only way it would really be worthwhile is if you did the third pass at -60 or less. 60C is a good mixing temperature, the only thing I would advise is not dumping frigid ethanol in the mix.
The rapid crashing traps oils in the globs and makes it harder to wash the waxes completely clean. The advantage to having everything hot is the gradual crash, it’s really just making the filtration faster/easier.
Why not do a room temp to take the bulk of gats out then freeze. I room temp filter then do 1 cold filtering and straight ro roto
Awesome, I assumed the third pass was unnecessary since we are already getting good crude test results back.
Would you advise a filter at the beginning before the first freeze? and if no frigid dump, would you advise allowing it to cool to room temp before dumping in the -20C ethanol to make the 10:1 ratio or just using the heated 60C ethanol to make a 10:1 ratio?
This is what I was wanting to do, but just wanted to ensure that it wouldnt cause problems in the process!
I would advise using room temp ethanol to bring it up to 10:1. I wouldn’t bother filtering at room temp unless you’re trying to put a lot of volume through a small filter, it can make the first cold pass easier if you’re stuck using little buchners to filter. Otherwise, it’s just a waste of time and filter paper.
I have always done a room temp to take the bulk of the fats. 30-50gallons usually and then wash the fats with cold solvent to get close to the 10:1 and then into the freezer minimum of 18hrs then through a 1micron stainless filter then its ready for the roto. Otherwyin my experience you have to keep stepping down your cold filtering micron papers and takes days. I can start on monday and its done and in the roto by Tuesday. Just my method and experience
What freezer do you use to take that volume to freezing in 18 hours ?
Just curious ?
Basic kenmore deep freezer that always has dryice in it to pack around the immersion chillers. Its all in 5 gallon buckets so it doesn’t take long to get cold.
Aha it might set someone on the. Wrong foot not knowing that only a freezer without some dry ice most lickly doesn t have enough power to get frozen in 18 hours 
You dont have any issues with di in your freezer? I was worried about the di offgassing and blowing the door off.
I was going to alter my wash to have my SS pots rest in the freezer to help keep frozen.
No i dont wven have them plugged in there just giant coolers basically, and there not air tight enough to have the lid blown off. Just dont stick your head down in there, there aint no oxygen below the rim
Worst case to be sure drill a small hole where there are no coolant lines in the freezer and have some plugs to plug it when not in use to off gas
All medical or lab freezers have a hole for temp probe wires
I was thinking of just shutting it and not locking it. if it’s too much pressure, the door should just pop the seal vs pop the door off.
Yes annd it will
In the door of any freezer there are no cooling lines so thats safe
I have 4 butane cilinders hard lined treu the temp probe hole in the medical freezer some rockwool between gaps
And no problems of ice forming (-86C)
I had someone tell me that you could do 18 hours in -40 freezer, what are your thoughts on that? 
See: Winterization
Yep. That works. To an extent. Depending on solvent ratio and initial extraction temps.
Using In House analytics to define the sweet spot for any given extraction operation would be my response.
Depending on scale and initial solvent of choice, there are alternate solvents & membrane (filtration) based solutions.
Thanks for
That is exactly the thread I was looking for earlier, thank you!
I don’t know the initial extraction temps but I do know she’s using a 10:1 (1L crude : 10L etoh). I’m used to the standard 24 hours at 20c and wasn’t sure if speeding up the process with a deeper temp would degrade the product or have any other adverse effects.
I suggested an Agilent 1220 HPLC as a minimum for in house testing.
You need to look at the wattage or the BTU’s of the freezer then calculate specific heat of the solvent/crude. you can then calculate the time needed to achieve the desired temp based on BTU’s per gallon and the time frame your working with. for example the specific heat of ethanol is .614 BTU’s/lb for 1 degree F so it would be .614 x 6.57 equaling 4.03 BTU’s to drop one gallon 1 degree in 1 hour if you want to get from 60f to -40f in 18 hours you would need 7,254 BTU’s or 2,121 watts at 100% efficiency. You will also need to factor in the thermal conductivity of your solvent mix as well and if you decided to go with jacket reactors, fluid flow rates through the jacket will play a part and can be easily calculate based off the delta T (difference in temp going in and out).
I prefer Methanol for winterization especially if its all going to be post prossed. Filters quicker with less losses. Down side is PPE is absolutely a must and the laten heat of evaporation is about 20% higher.
Not an issue if you LLE to hexane!