Proposed ASTM Standard Aims to Establish Consistent Moisture Testing for Cannabis Flower

*W. CONSHOHOCKEN, Pa.* — ASTM International is developing a proposed
standard (WK95556) that aims to identify an accurate technique to determine
percent moisture in cannabis flower, harmonization across and between
states for moisture determination.

WK95556 is being developed by the laboratory subcommittee (D37.03), part of
ASTM’s cannabis committee (D37).

According to ASTM member Morgan Keefer, for cannabis flower products, the
label often reflects a moisture conversion [dry weight percentage] which
means that all the numbers on the label are heavily impacted by how much
water was in the flower.

“The issue with this is there is no standard method for determining how
much water is in the flower (which is a basic method) so the methods that
are being used for this are all over the place and even the results are all
over the place,” says Keefer, senior accreditation officer at A2LA. “Some
laboratories may dry in an oven, they may use very hot oven temperatures
which evaporate more than just the water weight, they then count the whole
difference in weight before and after the oven as ‘water weight’ and
perform the conversion which, if done in this way, would guarantee that all
of the cannabinoid and terpene percentages increase across the board.”

The proposed standard is intended for use by testing laboratories; to be
implemented as a required method by state regulatory bodies; and to be
added to scopes of accreditation.
About ASTM International

ASTM International is a not-for-profit nongovernmental organization that
develops voluntary consensus standards and defers to appropriate government
authorities to determine the legal and regulatory framework regarding the
control and use of cannabis. Over 12,000 ASTM standards operate globally.