IIF YOU'VE VISITED a medical marijuana dispensary in Oregon, or if you've checked out the recently opened recreational stores in Washington, you've noticed the labels that list THC and CBD content—along with CBN, and any residual pesticides, molds, mildews, or other horrible things that you don't want to ingest.
Where do these numbers come from, and who does the testing?
Oregon law currently requires that all products be labeled with the name of the lab that did the testing, so an independent third party lab is a stamp of legitimacy. Meanwhile, it helps to understand exactly what labs are seeking when they perform tests. I consulted with Green Leaf Lab, a Portland-based independent tester of cannabis, to learn what they're looking for and how they find it.
CANNABINOL (CBN)—As mentioned previously ["A Glossary of Terms," July 23], there are more than 400 compounds in cannabis. The main ones that impact your brain and body are THC, CBD, and CBN, or cannabinol. We've explored the first two, but the third, CBN, is the result of THC degrading and oxidizing from exposure and heat, often due to poor storage. Ever found and smoked an old joint that had been sitting in a forgotten drawer, then discovered you couldn't move? CBN is the reason. This is why proper weed storage is crucial, dummy.
SOLVENTS—In the case of concentrates, the majority of these are made using butane. As such, labs test for any residual solvents that may remain from improper "purging" and sloppy production. These can include acetone, ethanol, propane, and chloroform. This is one reason many cannabis connoisseurs insist on water- or ice-extracted concentrates. They have a cleaner taste, and no one blew their damn fool hand off or burned down their double-wide when making them.
MICROBES—Testing labs also look for bacteria, yeasts, and molds. This is known as a microbiological screening, and is important for users with compromised immune systems from chemotherapy, AIDS, and other conditions, or individuals with strong allergies to these substances.
PESTICIDES—Not all cannabis is grown using organic methods. Oregon law requires that samples submitted for testing do not exceed 0.1 parts per million of these four pesticides: chlorinated hydrocarbons, organophosphates, carbamates, and pyrethroids. If a lab finds more than that amount, the sample is considered unusable.
HOW THE TESTING IS PERFORMED—If I tried to explain the methods and equipment used, I'd start carpet-bombing your dome with terms like "high-performance liquid chromatography," "mass spectrometer," "analytical columns," and shutupshutupSHUTUP. Green Leaf Lab's website (greenleaflab.org) has more detail about their specific process, but very roughly: A small sample of cannabis is placed in a solvent, which is blasted through a tube that allows for the various compounds to be identified and counted upon separation. From these results, they determine the final content of THC and the presence of any undesirables.