[Rattman111]

Hi folks,

Been soaking up the knowledge here for months and finally need to start a thread to get more info about vacuum purging. I'm reading very mixed responses regarding "average" purge times.

I am on my 3rd run through a BVV closed loop extractor. This run was 1/4 lb run through an 18" de-waxed column. Running a mostly indica blueberry strain. High quality product and frozen after drying for a week or so. Slightly ground up in food processor... roughly pea sized buds. Total nug run! After first purge/flip I measured 15g of oil extracted using about 1.5lb of butane. I'm very pleased with the yield!

I am on day 5 of my purge and the oil is STILL reacting to a vacuum. I'm getting tons of bubbles still although they seem to be totally clear for the most part. I've flipped the slab twice since initial purge. Using a BVV vac chamber... heater matt set to 97 degrees. Oil is at about 95 degrees using laser thermometer.

In an old thread Graywolf said "We purge in about a 1/6" to 1/8" film, at 115F and -29.5" Hg until the solvent bubbles cease, for shatter every time, assuming we are using reasonably fresh material."

I got the oil as thin as I could pour it. Definitely not thicker than 1/8 inch!

Why am I still getting bubbles after 5 days? Does oil visibly react to the vaccum or just the butane? Do I continue purging until all bubbles have ceased... or just until they are clear (like now)?

Thanks much in advance for your guidance!!

Regards,
Rattman

[Rattman111]

I'm also concerned about purging terps. Is that an issue of "time" or only of "temperature"??

[Rattman111]

I'm going to try increasing the temp to 102 on the digital mat... should get me to 98-100 degree oil..

[SkyHighLer]

It's my contention vacuum purging in a thin film at 115F at down to -29.5" Hg just until the bubbling slows to a crawl is adequate. Any residual butane is non-toxic, and can't be detected or recognized by your senses.

My argument is presented in full here (sorry it's a brain draining three pages long, but I believe it should hold up under the highest scientific scrutiny,)

https://www.icmag.com/ic/showthread.php?t=348869

[Rattman111]

Your argument makes sense to me SkyHi! ...and thank you much for the response! I'll have to go back and read it again a few times tho to understand all the numbers.

Please forgive my ignorance.... but are you saying the bubbles are fine as long as they are not moving around once they form under vac? Or do I need to wait until the slab is completely flat and void of any bubbles popping up before concluding that the purge is completed?

And it sounds like I really need to increase my temps if you are at 115F?! I know different plant strains react differently to the process, but I made a really nice stable shatter from a northern lights strain without going above 100f on the heat mat recently. I see a lot of guys (Brett Maverick included) shooting for an oven temp of 98f. I don't have an oven, I only have a BVV 2 gallon vac chamber.

Once again, I really appreciate the wisdom! Thank you!

[Rattman111]

Just found this older thread that talks about purge temps Sky. You made some great points.
Increasing temp to 115f now.
https://www.icmag.com/ic/showthread.php?t=334561

[Gray Wolf]

Originally Posted by Rattman111

Hi folks,

Been soaking up the knowledge here for months and finally need to start a thread to get more info about vacuum purging. I'm reading very mixed responses regarding "average" purge times.

I am on my 3rd run through a BVV closed loop extractor. This run was 1/4 lb run through an 18" de-waxed column. Running a mostly indica blueberry strain. High quality product and frozen after drying for a week or so. Slightly ground up in food processor... roughly pea sized buds. Total nug run! After first purge/flip I measured 15g of oil extracted using about 1.5lb of butane. I'm very pleased with the yield!

I am on day 5 of my purge and the oil is STILL reacting to a vacuum. I'm getting tons of bubbles still although they seem to be totally clear for the most part. I've flipped the slab twice since initial purge. Using a BVV vac chamber... heater matt set to 97 degrees. Oil is at about 95 degrees using laser thermometer.

In an old thread Graywolf said "We purge in about a 1/6" to 1/8" film, at 115F and -29.5" Hg until the solvent bubbles cease, for shatter every time, assuming we are using reasonably fresh material."

I got the oil as thin as I could pour it. Definitely not thicker than 1/8 inch!

Why am I still getting bubbles after 5 days? Does oil visibly react to the vaccum or just the butane? Do I continue purging until all bubbles have ceased... or just until they are clear (like now)?

Thanks much in advance for your guidance!!

Regards,
Rattman

No, you stop when the solvent bubbles cease, not to be confused with CO2 bubbles from decarboxylation.

Solvent bubbles are random sized and some large, while CO2 bubbles are small uniform fizzy bubbles.

Starting with Cotton Candy, at 115F and -29.5" Hg, with a couple flips, we are below 500ppm in less than four hours.

At 95F, viscosity and surface tension are higher, so harder for the bubbles to escape.

The best temperature is the temperature that your specific oil fully melts, usually between 110F and 120F.

[Rattman111]

Thanks Graywolf, and nice to meet you sir!!
And thanks much for all you do for the community!

My temps will be higher moving forward.
The slab has already improved after only an hour at the higher temp.

I would love to try the cotton candy technique instead of pouring.
I don't have a recovery pump but I do have a site glass on my collection vessle.
I have the BVV mini extractor with added 4x8 extension for the site glass.... so my collection vessel is 14 inches high by 4 inches wide. Is that too small to attempt this technique? Pulling a vac in those dimensions would have the muffin sticking to the sides for sure. I'm not understanding if the frozen cotton candy is expected to cling to the sides of the collection vessel or not.

[Gray Wolf]

Originally Posted by Rattman111

Thanks Graywolf, and nice to meet you sir!!
And thanks much for all you do for the community!

My temps will be higher moving forward.
The slab has already improved after only an hour at the higher temp.

I would love to try the cotton candy technique instead of pouring.
I don't have a recovery pump but I do have a site glass on my collection vessle.
I have the BVV mini extractor with added 4x8 extension for the site glass.... so my collection vessel is 14 inches high by 4 inches wide. Is that too small to attempt this technique? Pulling a vac in those dimensions would have the muffin sticking to the sides for sure. I'm not understanding if the frozen cotton candy is expected to cling to the sides of the collection vessel or not.

Thanks for the good thoughts!

A 4" dia x 14" high vessel would work, but would be limited in how much you could run at a time. It will fill the space and touch all surfaces, but it isn't sticky when dry, so not hard to remove, especially if you chill it first.

It is the high vacuum pump, as opposed to a recovery pump, that produces the cotton candy foam. You turn off recovery and turn on high vacuum when the visable LPG is gone and large "blurpy" bubbles are left.

[Rattman111]

24 hours at 115F did the trick friends!
Beautiful stable shatter in the end for me!

Thank you again for sharing your wisdom!