Testing the Moisture Content of Cannabis
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ASTM International’s recently formed committee on cannabis (D37) has approved its first two standards. Both deal with the aspects of moisture in cannabis.
According to committee members, cannabis is generally sold by weight, with a large measure of its quality determined by the amount of moisture it contains. The standards provide a procedure to determine the water activity in a cannabis sample (soon to be published as D8196) and the range of water activity suitable for safe and effective storage of a cannabis flower sample (soon to be published as D8197).
Committee member Jon DeVries, CEO of DeVries and Associates, notes that using the new standards will allow for more efficient study of the volatility of hydrocarbons within the essential oils of cannabis called terpenes. (The interaction of various terpenes is believed to provide therapeutic benefits associated with cannabis; however, as moisture leaves the plant, differential terpene evaporation occurs as well.)
“Incorporating these standards avoids the very real problem the industry experiences in which flower specimens are sent to a lab for testing, creating a time lag in which the batch from which the sample came is drying out,” says DeVries. He adds that the batch continues to dry as it is being packaged and made available to patients and others, resulting in a cannabis and terpene profile that no longer accurately reflects test results.
He said that the new standards could help producers avoid this situation in industry efforts to promote product safety.