Terpenes 101: Reading a COA Like a Connoisseur
- 3 Apr 2026
Every legal cannabis product sold in New York arrives with a Certificate of Analysis, or COA. It is the single most powerful tool you have for choosing flower intentionally. Once you know how to read it, the COA tells you how strong a product really is, what its aromatic personality will be, and whether it passed contaminant testing. Here is how to decode one in about two minutes.
What is a COA, exactly?
In New York, every cannabis batch must be tested by an Independent Cannabis Testing Laboratory (ICTL) licensed by the Office of Cannabis Management. The lab's report—the Certificate of Analysis—travels with the product all the way to the dispensary shelf and is linked from a QR code on the package. A proper COA lists:
- Cultivator and product details (strain, batch number, harvest date).
- A full cannabinoid profile (THC, CBD, CBG, CBN, and their acid forms).
- A terpene profile by weight percentage.
- Contaminant testing results: pesticides, heavy metals, microbials, mycotoxins, residual solvents, moisture, and water activity.
- A pass/fail stamp and the testing lab's signature.
If a shop can't show you a COA linked to the package—or the QR code on the package doesn't load a matching report—that is a loud sign the product isn't coming through New York's licensed supply chain.
Total THC is not THCa
Flower and concentrates generally list two numbers: THCa (the acid form found in raw plant) and Delta-9 THC (the psychoactive form produced when cannabis is heated). When you light a joint or vape a cart, THCa converts to Delta-9 through a process called decarboxylation. Because THCa loses a carboxyl group during this reaction, about 87.7% of the original THCa mass becomes Delta-9 THC. The industry-standard formula is:
Total THC = (THCa × 0.877) + Delta-9 THC
A flower labeled 22% THCa and 0.5% Delta-9 will come in around footer ~