Moisture correction is the arithmetic step that removes water from the denominator of a result. The lab first measures moisture content, most often by loss on drying: a weighed portion is dried under controlled conditions until its weight stops falling, and the loss is taken as water (plus some volatile terpenes, a known small bias). The as-received result is then divided by (1 - moisture fraction).
In practice
Total THC 18.6% as received, moisture 10.5%: corrected = 18.6 / 0.895 = 20.8% dry weight. The higher the moisture, the bigger the correction. A wet sample tested as received looks weaker; the same sample moisture-corrected looks stronger. Moisture is also a quality signal: cured flower around 10-12% w/w moisturebeing reviewed with water activity about 0.55-0.65 is in the safe, well-cured range.
Corrected (% w/w dry) = as-received (% w/w) / (1 - moisture %/100).
Don't confuse with
- Water activity test: measures free water availability (aw), not total water mass.
- LOD (limit of detection): same abbreviation as loss on drying, different meaning.
Myth check
Always check whether moisture correction was applied before comparing numbers. See buyer beware.
The amount of water in a material as a percentage of its weight; cured cannabis flower usually sits around 10-12% w/w, though measurement method matters.Terpenes are volatile hydrocarbon compounds built from five-carbon isoprene units; in cannabis they are made in the trichome heads and are a major part of aroma and flavour.Total THC is a calculated figure, Δ9-THC plus 0.877 × THCA, estimating the maximum THC a sample could yield after full decarboxylation.Dry-weight basis reports a result per gram of sample with its water removed, while as-received basis reports it per gram as delivered, water included; dry-weight figures are always higher.Bag appeal is how good flower looks in the bag or jar, frost, colour, density and trim, which sells cannabis but does not measure its quality.Holding dried cannabis in sealed containers so its moisture declines slowly and evenly over weeks, improving smoothness and aroma.A 0-1 measure of how freely available the water in a material is; for dried cannabis flower the accepted range is about 0.55-0.65 aw.A water activity test measures how much of a sample's water is free to support microbial growth, reported as aw from 0 to 1, with cured flower targeted around 0.55-0.65.Potency testing is laboratory measurement of a sample's cannabinoid content, normally by HPLC, reported as % w/w or mg/g for each cannabinoid plus calculated totals.A COA (certificate of analysis) is a lab's signed report of what it measured in a specific sample, such as cannabinoids, terpenes, moisture and contaminants, with methods and limits.
