After reading the “Cookie Monster Nug Run Review” in our first issue I was moved to provide a little insight in regards to the purging process that was mentioned with this butane extraction.
In the review it reads, “This nug run was extracted from a live resin and purged for 72 hours through a closed loop system extraction machine.” This butane extraction process refers to the removal of butane/propane (hydrocarbon residual solvents) from extracts once the extraction process is finished.
When using a closed loop butane extractor system for Cannabis Processing the butane/propane is introduced to the plant material by flooding the bottom of the column, or passing the solvent through the the top of the column where it saturates the plant material for about 30-40 minutes under extremely cool temperatures.The Solvent is then passed through the plant material that has been packed into stainless steel columns where hydrocarbons penetrate and extract Cannabinoids and/or Terpenes from the plant material. All of the extract, and Butane/Propane is dripped into the bottom of the extractor to a part called a “collection pot.” The plant material columns are then removed. Next, the collection pot is heated so that majority of the hydrocarbons used as a solvent can be distilled and retained for extractions in the future. At the end of the extraction process you are then left with roughly 95% cannabis oil and 5% propane or butane residual solvents in your collection pot. At this point it then still needs the 72 hour purge. The oil is then scrapped or poured onto large sheets of parchment paper, medical grade silicone sheets, or huge Pyrex dishes for a vacuum purge. The purging typically happens in an Across International vacuum oven. This is the point in the process where you can pin point temperatures and lower atmospheric pressures inside your oven to remove residual solvents without forfeiting the most loud aromas that we all cherish, the terpenes.
The purge is the most important factor in the consistency of your final product. Whether it will be live resin, shatter, budder, honeycomb, or honey oil. All other consistencies like distillates, isolates, rosin, Co2, etc. have additional refining, or completely different processes for extraction.
Live Resin Extraction
Live Resin is a different form of extract because there is no drying or cure process before it is extracted. The plant is simply chopped, and immediately frozen or extracted to retain the maximum amount of terpenes that may have been lost in the drying process. The high terpene content in this extract makes for a very runny/sappy extract that can be purged at room temperature around 70 degrees fahrenheit and 25hg (inches of Mercury) inside the vacuum oven. (72hours) This will typically produce an end product with 0-2% decarboxylation. So 98% of the thc content would test as THCA. Both Butane and Propane are great solvents for this method of extraction.
Shatter & Budder Concentrates
Shatter is often created by using butane to extract concentrates from a dried cured plant. It is a stable extract with higher THC and less terpenes then live resin extractions. This extract is typically purged between 90 and 100 degrees Fahrenheit before being finished at 30 hg(inches of Mercury) inside the vacuum. It works at a rate of 2-10% decarboxylation so (at max) 90% of the THC content will result in THCA and 10% would be THC9.Fully dewaxed BHO/PHO will likely end with this consistency regardless of the purge temperatures. I prefer Butane as a solvent for my dewaxed shatters.
Butter is the same as shatter only purged at a higher temperature at 100-125 Fahrenheit. Therefore it is slightly higher in decarboxylation, at 10-30%, so at max 70% of the THC content will be THCA and 30%THC9. Lower temperatures can be use to sugar up waxy extracts. The lipids hold in the terpenes aromas very well and PHO is my preferred method when making sugars and waxes.
Honeycomb & Honey Oils
Crumble and honeycomb butane extractions both purge at a temperature around 130-140 Fahrenheit and 50-60% decarbed before being run at 25hg (inches of mercury) inside the vacuum oven. Honey oil is done at a 150-180 Fahrenheit purge with 25hg (inches of mercury).
All Images from @profuse_extracts