Testing Cannabis for Water Activity
It may not have a famous name like heavy metal contamination or pesticide contamination, but water activity is one of the key indicators that your cannabis product will maintain its quality, freshness, and integrity throughout its expected shelf life.
What is water activity?
Water activity is a way to determine how susceptible cannabis is to microbial contamination. It is a thermodynamic measurement that indicates how tightly bound the water's available energy is - essentially how free-flowing and readily available the water in the product is. Water activity should not be confused with moisture content, which measures the total amount of water present in a product.
The higher the measured water activity in a cannabis product, the more freely water can be used by microbes as a food source or to support chemical and enzymatic reactions leading to spoilage and contamination. Anything higher than the recommended benchmarks can promote the growth of yeast, molds, fungi, and bacteria, and can also promote enzymatic production. However, cannabis flower should not be too dry: anything lower than the recommended benchmarks can cause some terpenes to deteriorate, resulting in little smell or flavor.
Why is water activity important?
Water activity is vital to cannabis product quality in three major ways:
Food and product safety. One of the primary reasons water activity is measured in food is to ensure that these products are not likely to develop microbial growth or harbor mold growth. This ensures quality, freshness, and most importantly, product safety, which is particularly important for patients who are more susceptible to any contaminants in flower that may be inhaled.
Long term storage. The shelf life of a cannabis product is greatly impacted by water activity. High water activity can mean that a cannabis product won’t last through the intended sell-by date on the package. Proper water activity levels ensure that your product won’t spoil or rot before it makes its way to customers or patients.
Product quality. Higher or lower than acceptable water activity levels in a cannabis product can degrade sensitive phytocannabinoid and terpene content.
How is water activity measured?
Expressed as aW, water activity measures the ratio of water pressure of a manufactured cannabis product, like an edible, against the water vapor pressure of water under the same conditions. Unlike a moisture analyzer, which simply determines water levels in the cannabis product, water activity requires more advanced equipment to detect and quantify this pressure. The newest emerging technology uses a tunable laser diode (TLD) to quickly and more reliably measure water activity. A chilled mirror dewpoint hygrometer can also be used.
Ideal water activity levels
Water activity results can range from 0.000 (devoid of water content) to 1.000 (pure, liquid water). To control cannabis product contamination, it is recommended for flower to have a water activity value between 0.550 and 0.650, and for cannabis edibles to have a water activity value of less than 0.85.
The difference between water activity and moisture content
While you may see these terms used interchangeably, that is not correct. Water activity is used as a way to determine how easily microorganisms can grow in a product, and indicates the potential for microbial growth, such as mold or mildew. Visit the moisture content page on the True Labs website to learn more about moisture content and requirements for testing moisture content as set out by the state of New Jersey.
Does New Jersey require water activity testing?
Many states have regulations in place requiring cannabis water activity testing. While New Jersey does not have water activity level testing requirements yet, the state of Maryland does, and NJ is currently following Maryland testing standards on an interim basis. It is still a good idea to test for water activity for product quality and the health of the patients and customers buying your product. Measuring water activity is an assurance that your flower won’t grow mold or otherwise develop contaminants in transit or while waiting to be sold at the dispensary.
In addition to staying in compliance with regulations, obtaining recommended water activity values in cannabis products has a huge benefit to producers of extending overall product shelf life. True Labs for Cannabis tests for water activity so that producers can gain confidence that final cannabis products stay clear of contamination and safe for consumers.
Why True Labs for Cannabis?
As a north-central New Jersey based analytical laboratory, True Labs for Cannabis is dedicated to the needs of Garden State Alternative Treatment Centers (ATCs), which include vertically integrated cultivators, producers, and dispensaries, and delivering high quality and compliant products to patients and adult use consumers. Our standards are designed to be more stringent than simply meeting requirements set out by the state, offering testing services that go above and beyond the bare minimum. We strive to bring the latest technology and processes to your cannabis or industrial hemp products, so your customers are assured they are only getting the best cannabis products.
True Labs for Cannabis is also a certified woman-owned business in the state of New Jersey, the only one in the state, and one of the few in the U.S. who can claim the same. Our CEO and founder brings a passion for quality, careful diligence, and compassion to True Labs, dedicated to building and enhancing the credibility for the entire legal cannabis testing industry.