Water activity refers to the water that remains at the surface of the cannabis plant that can sometimes lead to an increase of fungi and bacteria. Certain regulations put limits on the amount of unbound water a plant can contain. The regulations are intended to prevent growth of mold and bacteria. When cannabis is in storage, the amount of unbound water should be between the range of 55 and 65%.
Keeping measurements on the water activity in cannabis plants is important to keep the product protected from microbial contamination. When the water activity is measured to be at a higher amount, then it means that water can move more freely and microbes can use it as a source of food which can potentially lead to spoilage.
Generally, when the value of water activity grows, the chances of microorganism growth are higher. In scientific terms, water activity is the thermodynamic measurement that explains how closely bound the water’s available energy is. Water activity levels can range from 0.000, which means that it is void of all water and completely dry, while someone that is measured at 1.000 means that this would be pure water.
The perfect water activity value is considered to be under 0.600. In California and Oregon, water activity limits for cannabis are set at 0.650. To correctly measure water activity, one must determine the saturation vapor pressure and the vapor pressure of water in the sample at a certain temperature. Devices can take these measurements by using a tiny sample of the product that is inserted into a water activity meter.
Use of Term
The water activity in my plants was tested and found to be at just right right amount, so I think I will most likely be getting a good harvest this summer.