How to Read a Maine Cannabis COA for Terpenes (and Why Most Menus Don't Have Them)

What a Certificate of Analysis is

A Certificate of Analysis, almost always shortened to COA, is the lab-issued document that records the test results for a specific batch of cannabis or cannabis product. Every batch sold at a licensed Maine dispensary has a COA on file at the dispensary and (since 2023) reported to the OCP. The COA is generated by an OCP-certified testing facility using validated analytical methods, and it is the legal record of what is in the product.

The COA answers a single question: did this batch pass the safety and labeling tests the State of Maine requires for it to be sold to consumers? The COA also records optional data (like terpene profiles) when the cultivator paid for it. The mandatory tests are listed in 18-691 CMR Ch. 40, the Maine cannabis testing rule. The optional tests are whatever the cultivator chose to add to the lab order.

For consumers, the COA is the most reliable source of objective data about the product you are buying. Dispensary menu descriptions, budtender recommendations, and strain-name marketing are all subject to interpretation. The COA is the document the State of Maine accepted as evidence that the product is safe to sell and accurately labeled. If a COA says the THC content is 22% and the limonene is 0.4%, that is what is in the jar.

Maine's mandatory testing panel: eight categories, no terpenes

Under 18-691 CMR Ch. 40, every batch of adult-use cannabis sold at a licensed Maine dispensary must pass eight categories of analytical testing before it can be released for sale:

1. Cannabinoids — THC, THCa, CBD, CBDa, and a small number of minor cannabinoids, reported as percent of dry weight. This is the number that drives the menu price.
2. Water activity — a measure of moisture availability, must be below 0.65 to prevent microbial growth.
3. Foreign matter — visual inspection for stems, seeds, insects, hair, and other contaminants.
4. Heavy metals — lead, cadmium, mercury, arsenic. Required for all product types but with stricter limits for inhalable formats.
5. Microbial contaminants — total yeast and mold, plus specific pathogens (E. coli, Salmonella) for inhalable formats.
6. Mycotoxins — aflatoxins and ochratoxin A, tested because cannabis flower is susceptible to mold that produces these toxins.
7. Pesticide residues — a panel of 50+ compounds specific to cannabis production.
8. Ethyl acetate residuals — added in 2023, applies to extracts produced using ethanol or ethyl acetate as the solvent.

Notice what is NOT on that list: terpenes. Maine's mandatory testing panel does not include terpene analysis. The OCP has historically defended this choice by noting that terpene content is not a safety concern (terpenes are non-toxic at the concentrations present in cannabis), and that adding it to the mandatory panel would increase testing costs for cultivators without a clear safety justification. The result is that terpene data is an optional add-on, paid for by the cultivator when they choose to, and reported on the COA only when the test was conducted.

What a COA actually contains

A typical Maine COA runs 1-3 pages and is structured as a series of labeled sections, one per test category. Every COA includes the following header information regardless of the testing facility:

• Sample ID — a unique identifier that ties the COA to a specific batch in the cultivator's records
• Batch ID — the Metrc package tag identifier for the product
• Product type — flower, pre-roll, concentrate, edible, tincture, topical, etc.
• Strain / Cultivar — the name on the label (note: the strain name is self-reported by the cultivator, not verified by the lab)
• Test date — when the sample was received and analyzed
• Test methods — the analytical instruments and techniques used (typically HPLC for cannabinoids, ICP-MS for metals, qPCR for microbes)
• Pass/fail status — overall batch status, plus pass/fail per category

Below the header, the COA is organized by analyte category. Each category lists the analytes tested, the result for each (in the appropriate units — percent for cannabinoids, ppm or ppb for metals and pesticides, CFU/g for microbes), the action limit (the threshold above which the batch fails), and whether the result passed or failed.

At the bottom of the COA, the testing facility's name, address, license number, and signatures appear. The COA is a legal document; the testing facility is certifying the results under penalty of perjury. A COA that does not have the testing facility's signature and license number is not valid, and any dispensary selling product with an unsigned COA is in violation of OCP rules.

Where terpene data shows up on a COA

Terpene data appears on a Maine COA only when the cultivator paid for terpene analysis. The OCP does not require it, the testing facility is not required to offer it, and most cultivators do not pay for it. The result is that terpene panels are present on a minority of Maine COAs.

When terpene data IS on the COA, it appears in its own section, typically titled “Terpenes” or “Terpene Profile,” near the bottom of the document. The section lists each detected terpene by name, with the result reported as a percentage of dry weight (or sometimes as mg/g, which is the same number — 1% = 10 mg/g). The list is usually ordered from most abundant to least, and it includes a “Total Terpenes” line at the bottom.

Maine testing facilities that offer terpene panels typically use gas chromatography-mass spectrometry (GC-MS) for the analysis. The detection limit is usually around 0.01% by weight, which means anything below 0.05% is reported as a non-detect (ND) or a trace amount. The COA should also indicate the method detection limit (MDL) for the terpene panel; this is the threshold below which the instrument cannot reliably distinguish terpene from background noise.

The cultivators that routinely pay for terpene testing in Maine are the ones that treat it as a quality differentiator: Theory Wellness, HIGHLY Cannaco, select caregiver network brands, and a handful of smaller operators. If terpene data is on the menu or the product page, it is a sign the cultivator invested in the test, not a regulatory floor.

How to read terpene numbers

If you have a COA with a terpene panel, the numbers follow a consistent logic. The total terpene percentage is the most useful single number: it tells you the overall aromatic intensity of the product. As a rule of thumb, total terpene content above 1% is average for quality indoor flower, above 2% is high, and above 3% is exceptional. Anything below 0.5% total terpenes is unusually low and may indicate old, degraded, or poorly-cured product.

The individual terpene concentrations tell you the chemical profile. Above 0.5% of a single terpene is considered “dominant” in the profile; the cultivar's effect (if any chemical profile is predictive of effect, per the 2024 Johns Hopkins limonene research) is most likely to be driven by the dominant terpenes. Between 0.1% and 0.5% is considered a secondary contributor. Below 0.1% is trace and probably not pharmacologically meaningful at the dose you are inhaling.

For consumer decision-making, focus on the top three terpenes by percentage. The top three typically account for 60-80% of the total terpene content, and the secondary and tertiary compounds have diminishing predictive value. A cultivar that is 0.8% myrcene, 0.4% β-caryophyllene, and 0.2% limonene is going to have a substantially different effect profile than one that is 0.3% myrcene, 0.2% β-caryophyllene, and 0.7% limonene, even though both have similar total terpene content. The budtender at any licensed Maine dispensary can usually help you translate the numbers into an effect description if you ask.

One important caveat: terpene percentages on a COA are measured at the time of testing, not the time of sale. Terpenes are volatile, and storage conditions (heat, light, oxygen exposure) cause them to degrade over time. A cultivar that was 2.5% total terpenes when tested in March may be 1.8% by the time you buy it in August. The Maine-required testing and the optional terpene testing both happen at the time the batch is packaged; the COA is a snapshot, not a permanent record of the product's terpene content.

Maine's open testing data portal

The OCP publishes aggregated testing data at maine.gov/dafs/ocp/open-data/adult-use/testing-data, with quarterly updates. The data portal includes the mandatory test results for every batch tested in the state, organized by analyte category and testing facility.

What the data portal is good for: understanding overall pass/fail rates by analyte category (microbes fail most often, then pesticides, then heavy metals), identifying which testing facilities are doing the most volume, and tracking the industry-wide trend in test results over time. The 2025 data showed a roughly 6.4% overall fail rate, which is consistent with what other state programs report.

What the data portal is NOT good for: looking up terpene data for a specific product. The portal publishes the mandatory test results, not the optional terpene panels. For terpene data on a specific Maine product, you have to ask the cultivator or the dispensary directly. The data portal is also not updated in real time — it lags by a few weeks to a few months, depending on the quarter.

Sample walkthrough: a typical Maine COA

To make this concrete, here is what a typical Maine dispensary COA looks like in practice. The product is a 3.5g jar of indoor flower, the cultivator paid for terpene testing, and the COA runs about 2 pages.

Header: Sample ID 25-04-1987, Batch ID 1A4060300000001000001234, product type “Cannabis, Flower,” cultivar “Maine Treehugger,” test date April 18, 2026, testing facility “ProVerde Laboratories” (Maine license #TL-014).

Cannabinoids: THC 22.4%, THCa 0.31% (total THC 22.7%), CBD 0.08%, CBDa <0.01% (total CBD 0.09%). All within Maine's required reporting precision. Pass.

Water activity: 0.582 (limit 0.65). Pass.

Foreign matter: None detected. Pass.

Heavy metals: Lead <0.1 ppm (limit 0.5), cadmium <0.05 ppm (limit 0.2), mercury <0.02 ppm (limit 0.1), arsenic <0.1 ppm (limit 0.2). Pass.

Microbial: Total yeast and mold 1,200 CFU/g (limit 10,000), E. coli ND, Salmonella ND. Pass.

Mycotoxins: All five regulated mycotoxins ND. Pass.

Pesticides: All 50+ screened compounds ND. Pass.

Terpenes (optional, present because the cultivator paid for it): Myrcene 0.42%, β-caryophyllene 0.31%, limonene 0.18%, α-pinene 0.08%, linalool 0.06%, terpinolene 0.04%, humulene 0.03%, ocimene 0.02%, bisabolol 0.02%, others trace. Total terpenes 1.21%. The dominant terpene is myrcene, with β-caryophyllene secondary and limonene as the third. The budtender at the dispensary would describe this as a myrcene-dominant, relaxing, body-effect profile with some β-caryophyllene for anti-inflammatory contribution.

That last paragraph is the kind of effect translation a knowledgeable budtender can do at the register. The COA gives you the raw numbers; the budtender's job is to translate the numbers into the consumer-experience language you are used to hearing on the menu.