Chemical Separation: Chemical separation is another technique used to remove the trichomes from the plant matter; but it is far different from mechanical because it uses what are sometimes very volatile gases for extraction. However many of the techniques are remarkably safe under the right conditions, and furthermore, many of the solvents used are not even very volatile. Regardless, there are many other parameters to consider when discussing solvent VS. non solvent extractions. Bottom line: solvent-based extractions are defined that way because they chemically bind to particles of resin on the plant on a molecular level, in a way that water does not.
Alcohol: One solvent that is sometimes used to extract cannabis flowers, however it is more frequently used to dissolve raw concentrate for a secondary distillation process. The legendary cannabis medicine that more or less started it all, “Rick Simpson Oil,” is a raw extract made with alcohol. Alcohol is somewhat dangerous to use in extraction processes, but is easily contained and removed from the final product. Dabbable products made with alcohol include The Clear and both THC and CBD isolates.
Butane: Butane is easily the most controversial solvent used in the process of making concentrates, and a lot of this is indirectly due to the radical popularity of the product made with it. BHO or Butane Hash Oil is made by filtering cured, dried cannabis through liquid butane gas. It may sound a little sketchy if you’ve never heard of it, but the process, when done correctly, is actually quite safe and the resulting product, if processed correctly, will be completely free of residual solvent. Why would somebody want to use butane gas to create raw cannabis extract? There’s actually a really good reason. Butane is an extremely non-polar molecule, meaning, in brief, that it binds with great efficiency to the fats, lipids and oils produced by the cannabis plant. This means that not only will it pick up the vast majority of cannabinoids on the plant matter, but it will also pick up all the terpenoids as well. The terpenoids are all of the essential oils, just like the ones you buy at Whole Foods, that give cannabis such a wide variety of unique and pungent aromas. Therefore, hash made with butane typically has considerably more flavor and aroma than any other type of solvent-based concentrate. This makes it an extremely valuable resource to Maine’s recreational cannabis industry.
Carbon Dioxide: Carbon dioxide is easily the safest solvent used to create cannabis extract, for one reason in particular: unlike competitors butane and alcohol, carbon dioxide is actually flame-retardant, rather than combustible. This means that, even in the event of a gas leak, there would be little or no risk of fire; however, the gas does need to be kept under pressure, and so, just like butane, it requires the presence of a complicated system of pressurized tanks and valves to contain it. Carbon dioxide is an efficient solvent, but it requires much higher levels of pressure than butane, and therefore requires what is known as a Supercritical CO2 Extraction unit, making it much more costly to get started. Furthermore, CO2 does not have a reputation for producing particularly flavorful concentrate, and is more useful for production of medical grade products.
Pros VS. Cons: These solvents are extremely useful for the commercial manufacture of concentrates. They yield efficiently, consistently, and regularly. They yield high quality, high quantity concentrates- and yet this consistency is also a problem. The fact is, you can take any material, grown as poorly as material can be grown, with pesticides and toxins galore, and make extracts that look fantastic with it. Fortunately we have testing facilities to make sure we aren’t smoking poison, but in any event what we’re smoking might not be organic if we’re talking about solvent.