# Moisture content

> 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.

- Canonical: https://genetixbay.com/knowledge/glossary/moisture-content.html
- Also written: MC, water content, moisture percentage, % moisture, moisture level
- Glossary category: Harvest, drying and curing · Evidence: Supported
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

Moisture content (MC) is the mass of water in a sample as a percentage of its total (wet-basis) mass. Fresh cannabis is around 75-80% water; well-dried and [cured](https://genetixbay.com/knowledge/glossary/curing.md) flower is commonly cited at about 10-12% w/w.

## In practice

Growers estimate it from weight. A plant typically loses about 70-80% of its [wet weight](https://genetixbay.com/knowledge/glossary/wet-weight.md) in drying, so [dry weight](https://genetixbay.com/knowledge/glossary/dry-weight.md) is commonly about 20-25% of fresh weight. Weighing a marked jar or test bud through the dry shows how fast you're going.

House position: what matters during the cure is the bud's moisture content and [water activity](https://genetixbay.com/knowledge/glossary/water-activity.md), not [jar RH](https://genetixbay.com/knowledge/glossary/equilibrium-relative-humidity.md) as such. Curing is a slow, steady decline in moisture, not holding it constant. MC and aw are related but not identical: two cultivars at the same MC can sit at different aw.

## Units and formula

MC (wet basis, %) = (wet mass - dry mass) / wet mass × 100.

## Don't confuse with

- **Water activity**: how available the water is, 0-1.
- **Dry-weight basis**: lab reporting convention for [cannabinoids](https://genetixbay.com/knowledge/glossary/cannabinoid.md).
- **Relative humidity**: water vapour in air.

## Related terms

[Water activity](https://genetixbay.com/knowledge/glossary/water-activity.md), [Equilibrium relative humidity](https://genetixbay.com/knowledge/glossary/equilibrium-relative-humidity.md), [Wet weight](https://genetixbay.com/knowledge/glossary/wet-weight.md), [Dry weight](https://genetixbay.com/knowledge/glossary/dry-weight.md)

## Read more

- [Drying cannabis: the 60/60 method and water activity](https://genetixbay.com/knowledge/harvest-cure/drying.md)
- [Curing and burping: jars, humidity and how long](https://genetixbay.com/knowledge/harvest-cure/curing-burping.md)

## Sources

1. ASTM D8197. Standard Specification for Maintaining Acceptable Water Activity (aw) Range (0.55 to 0.65) for Dry Cannabis Flower. ASTM International. https://store.astm.org/d8197-22.html
2. ASTM International, Standardization News. Two cannabis standards you should know about (D8196 water activity measurement; D8197 range). https://sn.astm.org/node/2445/printable/print