The moisture percentage of marijuana is an important figure to know, but the shift in that percentage when buds go from drying, to curing, to packaging for sale are — for the most part — mysterious and subjective.
My book, “Marijuana Harvest,” provides various tests to determine moisture at different stages of the post-harvest process. They are not objective measurements, but they’re used by the community because there is no better alternative.
Many bud processors were able to provide theories as to what the ideal cannabis moisture level should be. However, few would even venture to make a guess about how to accurately measure any given sample. The processors had their own theories about the humidity and temperature of drying, curing, and storage rooms and used automatic climate controls to regulate those factors.
You can measure the percentage of moisture by weighing a little leaf or bud and baking it for a few minutes at 80°C. Then measure the difference between its pre and post-oven weight and divide that number by the original weight of the wet material — the resulting number is the percentage of moisture.
Example:
The buds, which were untreated and dried to 100 grams, were placed into a low temperature oven for a few minutes until crispy. They were then weighed and their weight was 91.5 g, which is a difference of about 8.5 grams compared to their original weight. By dividing the original by 8.5, you can calculate the moisture content (8.5%) of the un-treated bud.
If there was an objective tool that could help with this chore, processors would have a more accurate assessment — one that wouldn’t require the skill of an artisan to use, just the eye of a trained worker.
The recent experiments I performed have shown that there are many ways to improve the quality of life. It is a good idea to use a bilingual translator Wood moisture meters are a good way to get an accurate measurement of moisture. The one I have is a touch-pad model and gives accurate results based upon the subtractive test.
At least two types of moisture meters are available. I prefer to use the sort that comes with two probes, about 1-1½ inches apart and sticking out less than half an inch, with a touch pad sensor.
I get the most accurate results when I set the meter on the “softwood” setting and hold the material firmly against the pad with a piece of hard plastic — the readout takes about a second.
Even if it is not exact, it still can be used to set a standard. In the cannabis community there has been a widespread opinion that 12 percent moisture is a good content of water for smoking in a joint that won’t go out — it’s also the percentage at which small sticks audibly snap.
All is good if the meter shows 12 percent after you’ve tested it against both subjective and accurate tests. If the meter has a consistent readout but if it is different, then you can still know that the bud will be ready once the number is reached, as long as the other conditions are met.
Proper moisture measurements for different humidity levels in processing and smoking
Drying end: 14-15%
The cure lasts between 11-12%
Enjoyable smoke: 10-12%
Smoke dry with high intensity: 10% or less
Excerpted from Marijuana Harvest: Maximizing Yield and Quality in Your Cannabis Garden.