Cannabis processors have a tight moisture target to hit when drying. Too dry, and you destroy trichomes and profits. Too wet, and you get mold, sick customers, and a damaged reputation. How do you get the precision you need to hit the sweet spot? And how do you package to make sure you stay there? Water activity/RH works in tandem with moisture content to transform the way you monitor and control moisture during drying, packaging, and storage. Result: a level of control over your process that allows you to consistently hit the sweet spot that maximizes profit and guarantees safety and quality. In this 30 minute webinar, you’ll learn: • what water activity is and why it’s an essential measurement for cannabis processors • what you need to know about how water activity predicts microbial growth • how to use specific water activity limits to maximize quality and minimize destruction of terpenes • why you should control water activity in the drying process to maximize profitability, control potency, and guarantee safety • how to prevent over-drying and excessive weight loss in the drying, curing, packaging, and storage phases Brian Rice, Director of R&D at Boveda, and John Russell, METER Food Application Support Specialist, will co-present. The webinar will be followed by a 10 minute live Q&A with the presenters.

2. Brian Rice, Boveda
Head of R&D
More than 20 yrs experience
Cannabis storage
John Russell, METER Group
Application Support Specialist
13 yrs experience
Cannabis moisture control
Introduction WATER ACTIVITY AND CANNABIS 2
WATER ACTIVITY AND CANNABIS

3. Brian Rice
Director R&D - Boveda
Nov 2019
Maximizing Cultivation Profits
Through Post-Harvest Humidity Control

4. • Understand how evaporation post harvest affects cannabis
• Gain understanding of water activity (aW), the recognized ASTM measure for determining cannabis
safety
• What is the target moisture level for cannabis flower and understand how it directly impacts
cannabinoids
• How fine-tuning aW levels to their sweet spot drives quality and economic gains
AGENDA

5. • Founded 1997
• Privately held
• Headquarters: Minneapolis, MN
• Defined and built the category of 2-way humidity
control
• Primary Markets:
• Premium Cigars
• Music
• Cannabis
WHO IS BOVEDA?

6. BOVEDA’S PATENTED TECHNOLOGY

7. What is 2-way humidity control?
• Adds or removes water vapor, as needed, to maintain product at the ideal RH
• Water vapor can pass through the Boveda film very quickly to respond to the outside environment.
• Will quickly bring contents and internal environment of a container to RH equilibrium
• Dials in to a predetermined RH (like setting thermostat)
Boveda is not a 1-way humidity controller.
• Desiccants strive to achieve 0% RH (dry).
• Humidifiers push out 100% RH (wet).
WHAT IS BOVEDA?
Boveda is a 2 –Way Humidity Controller
Maintains headspace at a constant RH
Responds to climate changes

8. 1. Terpenes
• Maintain trichome health
• Monolayer
2. Moisture & Weight
• Why it is critical to maintain moisture and its economic impact
3. Cannabis Quality & Brand Reputation
• Prevent mold, over-dry Bud and maintain safe/fresh cannabis
WHAT CAN EVAPORATE?

9. PREVENT EVAPORATION OF TERPENES

10. 12 days
HOW DO TERPENES EVAPORATE?

11. HOW DO TERPENES EVAPORATE?
1 month

12. 2 months
HOW DO TERPENES EVAPORATE?

13. 2 months
HOW DO TERPENES EVAPORATE?

14. • Dry trichomes are brittle, fragile, and have lost potency.
• Keep cannabis between 55% and 62%RH.
• This range promotes healthy, hearty and hydrated
trichomes.
• Trichomes remain flexible and preserve cannabinoids.
PREVENT EVAPORATION OF TERPENES

15. PREVENT EVAPORATION OF TERPENES
(MONOLAYER)
These evaporate without monolayer.
Monolayer formed around trichome
head.

16. • The absence of terpene smell in your container with humidity control is
good!
• Monolayer of water stops terpene evaporation!
• Boveda studies show zero terpene loss when monolayer is formed.
• This layer of H2O keeps trichomes hydrated and prevents oxidation.
PREVENT EVAPORATION OF TERPENES
(MONOLAYER)

17. PREVENT EVAPORATION OF MOISTURE & WEIGHT
• Cannabis aW sample study across 5 states in 2018
• Multiple strains tested from different dispensaries
• All in different styles of packaging
• Almost 90% of these were below 0.55 aW.

18. Typical Supply Chain
PREVENT EVAPORATION OF MOISTURE & WEIGHT
EVAPORATION

19. So what evaporates between when a bud is harvested on the farm
to when it reaches your local dispensary?
1. Water weight is lost = Loss of Revenue
2. Dehydrating bud = Loss of Terpenes & Cannabinoids
3. Overly dry bud = Compromised Trichome Health
PREVENT EVAPORATION OF MOISTURE & WEIGHT

20. Start Weight End Weight
5% drop in RH = $15,000 lost due to H2O evaporation!
PREVENT EVAPORATION OF MOISTURE & WEIGHT

21. PREVENT EVAPORATION OF QUALITY & BRAND

22. PREVENT EVAPORATION OF MOISTURE & WEIGHT

23. Rehydrating from dry using humidity control
Start Weight End Weight
12% increase in RH = ~$48,000 gain in revenue!
PREVENT EVAPORATION OF MOISTURE & WEIGHT

24. • Reduced sales
• Consumer Repeats
PREVENT EVAPORATION OF QUALITY & BRAND
PREVENT EVAPORATION OF QUALITY & BRAND

25. • …maintaining healthy, hearty, and hydrated trichomes.
• …keeping cannabis safe and hydrated between 55% and 62% RH.
• …creating a monolayer of H2O on trichomes that locks in terpenes and
cannabinoids.
• …preserving packaged weight, prevent mold, and avoid costly recalls.
RH CONTROL MAXIMIZE PROFITS BY...

26. THANK YOU

27. WATER ACTIVITY AND
CANNABIS
John Russell
Application Support / Account Executive
METER Group, Inc. USA

28. CONTENTS
Microbial Growth
Common Molds
Water Activity Mode of Action
Water Activity Standard Methods
Moisture Content Challenges
Cannabis Isotherms
Temperature Effect
Controlling RH in the Drying Process

29. WHY DO PROCESSORS
OVERDRY?
■ They want to avoid safety issues.
■ They don’t know the RH of their cannabis.
Microbial Growth WATER ACTIVITY AND CANNABIS 29

30. MICROBIAL GROWTH

31. MICROBIAL GROWTH
■ Scott (1953 & 1957) showed that microorganisms have a limiting water activity level below
which they will not grow.
■ Water activity, not water content, determines the lower limit of available water for microbial
growth.
Microbial Growth WATER ACTIVITY AND CANNABIS 31

32. COMMON MOLDS
IN CANNABIS
■ Aspergillus
■ Botrytis
■ Penicillium
■ Cladosporium
■ Mucor
■ Rhizopus
Common Molds WATER ACTIVITY AND CANNABIS 32

33. INHALING MOLD SPORES
■ Can cause fungal infections in the lungs
■ For healthy individuals, a fungal infection will be much like a chest cold.
■ For the immunocompromised, a fungal infection in the lungs can be life threatening.
– cancer patients
– HIV patients
– elderly
Inhaling Mold Spores WATER ACTIVITY AND CANNABIS 33

34. WATER ACTIVITY
MODE OF ACTION
aw = 0.95 aw = 0.90
Water moves out to
lower aw and turgor
pressure is lost.
aw = 0.93
aw = 0.90
The microbe tries to adapt by
altering its membrane make-
up or by reducing its aw to
maintain turgor pressure. It
will produce or transport in
small solutes to reduce its aw.
AA’s
Polyols
Sugars
AA’s
Polyols
Sugars
aw = 0.93
aw = 0.90
Unable to reach equilibrium with its
surroundings, the microbe will remain in the
lag phase with no growth or will begin
sporulation and go dormant, which can only be
reversed by ideal environment conditions.

35. GOVERNMENT COMPLIANCE
Water activity is a critical parameter for compliance.
Cannabis
ASTM D8196
▪ Determination of Water Activity in
Cannabis Flower
Pharma: USP Method <1112>
▪ ISO 29621: Microbial Control for Cosmetics
▪ ICH: Part 1A & Part 8, decision tree 6 & 8
Other
AOAC 978.18
Compendium of Microbiology Water
Activity Method Chapter 64
ISO21807
USP1112
Government Compliance WATER ACTIVITY AND CANNABIS 35

36. SWEET SPOT
Sweet Spot WATER ACTIVITY AND CANNABIS 36
LOST QUALITY/PROFITS
MOLD/MICROBIAL
GROWTH

37. MOISTURE CONTENT
CHALLENGES
■ Has no standard -- no definition of what is “dry”
■ Many different methods, most involving heat
– Each gives a different answer.
– Is water the only thing that volatilizes?
■ Many sources of variation
Moisture Content WATER ACTIVITY AND CANNABIS 37

38. CANNABIS ISOTHERMS
ADSORPTION CURVE
Adsorption Curve WATER ACTIVITY AND CANNABIS 38

39. TEMPERATURE EFFECT
Water activity is temperature dependent.
● Generally, higher temperature leads to higher water activity.
● The relationship between water activity and temperature for a given product
is consistent.
● Higher temperatures lead to increased rates of decarboxylation.
Temperature Effect WATER ACTIVITY AND CANNABIS 39

40. CONTROLLING RH IN THE
DRYING PROCESS
Dangers of high RH/water activity
● Water activity determines whether mold, fungus, and microbes can grow.
● Water activity determines quality (chemical and physical reaction rates).
How to know when the moisture is right
● Moisture content is not an adequate indicator.
○ not related to quality
○ lacks the precision
● Water Activity = RH
○ needs to be measured during drying
○ lets you hit the sweet spot
Drying Process WATER ACTIVITY AND CANNABIS 40

41. CONCLUSIONS
■ Dry to the right water activity level to hit moisture sweet spot.
– 0.55-0.62 aw
■ Overdry → loss of quality & profits
■ Underdry → mold & microbial growth
Conclusions WATER ACTIVITY AND CANNABIS 41

42. REFERENCES
Centers for Disease Control (CDC).
Scott, W. (1953) “Water relations of Staphylococcus aureus at 30 degrees C.” Australian journal of biological sciences 6 4 : 549-64 .
Scott, W. (1957) “Water relations of food spoilage microorganisms.” Advances in Food Research 7: 83-127.
Troller, J. A., D. T. Bernard, and V. W. Scott (1984) Measurement of Water Activity. In: Compendium of Methods for the Microbiological Examination of
Foods. American Public Health Association, Washington, DC, pp.124–134.
US Food & Drug Administration (2017) Food. Current Good Manufacturing Practices (CGMPs).
USP 32–NF27 Page 606, Pharmacopeial Forum: Volume No. 30(5) Page 1709
References WATER ACTIVITY AND CANNABIS 42

43. QUESTIONS?