Standard Historical Last Updated: Dec 17, 2020
ASTM D8196-18

Standard Practice for Determination of Water Activity (aw) in Cannabis Flower

Significance and Use

5.1 This practice is designed for use on cannabis flower by cannabis producers, processors, dispensers, testing laboratories, and end users. aw testing at any point in the supply chain is an important element in ensuring the safety and quality of cannabis flower. Testing can occur spontaneously at any point in the supply chain by regulatory agencies, suppliers, and customers.

5.2 This practice is an important endpoint in determining whether a cannabis flower sample is being stored under optimal storage conditions (see Specification D8197).

5.3 Analysis of water activity should be considered an important quality control step in ensuring a cannabis flower sample is being stored under optimal storage conditions to prevent mold and/or other microbiological growth and/or breakage.

5.4 Maintaining the requisite aw throughout the supply chain from completion of drying through merchandising ensures safety and quality for the consumer.

5.5 Water activity is used in many cases as a critical control point for Hazard Analysis and Critical Control Points (HACCP) programs. Controlling aw should not be seen as a kill step.7 Rather control of aw focuses on preventing the growth and proliferation of microorganisms.

5.6 This practice is designed for use by trained technical individuals with minimal knowledge of complex analytical chemistry procedures.


1.1 This practice covers the recommended procedure for determining the water activity (aw) of a cannabis flower sample.

1.2 Units—The values stated in SI units are to be regarded as the standard. Water activity is a ratio, and thus is without unit designation.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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Book of Standards Volume: 15.10
Developed by Subcommittee: D37.04
Pages: 3
DOI: 10.1520/D8196-18
ICS Code: 65.020.20