Purging refers to the process that is used to remove any leftover solvents from a cannabis concentrate. Such solvents that need to be removed are usually butane or propane. This ensures that the end-result of cannabis concentrate is completely safe and ready to consume.
There are some cannabis concentrate users that will say that it’s not possible to completely purge a concentrate of solvents, but that is the desired outcome. If butane oil is not purged, then users will be consuming a product that isn’t of high pharmaceutical quality. Purging the concentrates usually will require a vacuum to heat the product at a temperature that is around just less than the atmospheric pressure. Molecules will heat up and discharge the gas and once the pressure is turned down, the gas will then be released and the vacuum oven draws it out of the chamber.
This method is known to be the best way to purge, but it tends to be financially costly, so sometimes it is not the most popular or preferred method if people are doing this in their homes. One other purging method is a water-based one where a vacuum pump is used to extract the solvent into a dish that is floated in hot water.
The goal is to evaporate the solvent from the oil. Sometimes, the entire purging process can be avoided if a solvent that isn’t considered to be too harsh is used. Dry sieve and water hash are produced without utilizing any type of solvents and CO2 extraction also doesn’t need purging either.
Use of Term
I prefer to do the purging process on my concentrates to remove any of the excess solvents that were used to make it. I prefer to avoid consuming anything other than the concentrate itself, so purging gives me a peace of mind.