If you leave a mixture of THC and terpenes that have a magically identical boiling point to thc, eventually the THC will be all that remains, bc it’s vapor pressure is so low that it’s not volatile, whereas the (similar boiling) terpenes will evaporate.
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So the turps would boil then the thc would boil after? While maintaining the same temps?
The terps would evaporate regardless of temperature and the thc would not. They aren’t boiling exactly, but they would still be loosing mass.
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So the vapor pressure is a measure of volatility?
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Absolutely
Steam distillation makes use of the powerful vapor pressure of water to grab things that have enough vapor pressure. This is why cannabis terpenes are steam distilled to make cannabinoid free oils.
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So if you were trying to remove terpenes you’d want to use something with a high volatility and a low affinity for cannabinoids?
Seems like options are
Nitrogen
Steam
Pentane
Is there anything else that makes sense?
Honestly, I can’t really answer that well. I thought it would be simple but having higher fats/terpenes likely changes storage conditions compared to an extract that is mostly thca. How solid is it at 75F, how opaque is it? Etc. I’m going to think about this a bit more and I’m sure I’ll come up with a slightly better answer.
Anyone else? Many of you deal with this daily…
I’d think that a material that is substantially thca would be easier to store, and that fats and terpenes would solvate the material slightly, and promote little sugar crystals etc.
So if you had one product that was from aged weed, made with a tube and butane, doing only a light pass rather than a complete extraction, it may be largely thca and thus be best to store very cold and away from air and light. However another material which was done with a properly blended butane/propane/etc mix and fresh dope and run to completion in a closed loop, may have enough “solvent” (natural products from the plant) to nucleate under similar conditions.
Can anyone else help?
I replied to the wrong spot 
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Yeah I meant all of those under vacuum 
I’m hoping to do the dewatering and turpene removal at the same time. Seems like nitrogen is the way to go…
Actually I guess you could still have the plant dry if you used steam as well…
How would you recommend storing shatter prior to and after packaging in bulk? Do you recommend room temp or refrigeration? I need it to stay as stable as possible. I have had it at room temp for days but getting worried. I am not in a cold part of the country…Thank you
From what I know; most things are less stable in heat, oxygen, and light. So vacuum sealed/nitrogen fill, and in the fridge/freezer is your best bet?
warmer temps can induce sugaring, which isn’t necessarily a bad thing… its just not shatter anymore.
max shelf life is most likely achieved in a cool, dark, and dry place. If it is in a container, filling the headspace with nitrogen like tweedle said would be a great idea to reduce oxidation.
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Wouldn’t want that to happen
isnt that too low??? its boiling poing is 170ish
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Not sure if you were able to solve this issue but if you’re drying on a roto initially I have noticed that leaving the extract on for an additional 10-15 minutes after the last drop of EtOH has come off makes a difference in the Vac oven. Setting the temp around 95F and flipping every 12 hours seems to work for us. Always keep full vac after the initial muffin calms down.
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I usually pull it off the Roto when the solution is viscous and begins to bubble around the entire flask. Also, the quicker you pour it after the roto the better…less material left behind on the inside of the flask.
You Roto until no etoh drops at all ?? What is the deepest vac you pull on the roto?
Yeah that sounds like you’re getting it down to a pretty low concentration of EHO and yes the quicker you are the hotter the flask stays which allows you to get more extract out. 45mbar is what we pull. You will see the last drips come off the condensation column then wait 10 min before pulling it off.
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Could have been the extra terps.
Just to help everyone still interested in this thread in our lab we have actually adjusted our slab purging procedures which have given great success and far less sugaring than before.
Upon initial pour we allow the slabs to go through an initial purge for about 90 minutes or until they become stagnant. By this I mean very little bubble activity. Kill the vac and head to the freezer for your first flip! After this flip you should see another surge of bubbles. I suggest flipping at least 5 to 6 times every 90 minutes on the first day of pouring. This will allow the majority of your ethanol to come off very rapidly. The first 3 flips may require the freezer but this is strain dependant and if you’re good enough you’ll only need to go in there for the first flip.
If you see sugar just pick it out, be sure to get a wide area around the sugar so you don’t allow it to keep spreading. I usually take 1 inch from the sugar spot away.
Our slabs usually dry in about 2 days, our regulations call for below 5000 ppm ethanol. If you don’t have access to an in-house lab I would keep flipping every 90 minutes for 3 days and your slabs should be well below the 5k ppm limit! Hopefully this helps some of you guys level up and get that fire shatter!
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Can you share updates of what worked with you?
Perform cryoethanol =<40C on cold flower, reduce in the roto at 35C, once reduced similar to maple syrup consistency, pour slabs, purge at 95-98F and full vac (control the vac over the next 90 minutes to ensure no overboil or loss), after this initial muffin stage the bubbles will stop forming, let it dry at full vac for 18-24 hours. Then flip the slab initially, cont full vac and same temp 95F it will bubble on that side a little more but not like the initial purge. Flip every 8-12 hours for a couple days. 3 days should get the etoh out. Then remove the vac and increase the heat to ~105-108F (Strain dependent) and flatten out the slabs ( if you go past 110F for too long you may start seeing come sugaring. good luck
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