Why does relative humidity matter for cannabis storage and what exactly is relative humidity? Without getting too technical, this post will serve to enlighten the interested connoisseur and reinforce those scientific principles that make your herb stay fresh.
Relative humidity (RH) is the ratio of the partial pressure of water vapor in an air-water mixture to the saturated vapor pressure of water at a prescribed temperature. That’s as technical as it gets, it’s all downhill from here.
Cannabis buds are flowers. Flowers, after they are picked and cured, lose water and evaporate. Flower buds, like the one’s we’re trying to store, are extremely susceptible to water loss. If the flowers’ trichomes lose too much water, then so will its flavor, taste, aroma and potentially potency. Trichomes, from the Greek meaning ‘growth of hair,’ acts as a shield, protecting the plant from predators and insects as well as producing a resin that helps to insulate the plant from UV-rays and low humidity. Trichomes are where all of the goodies are stored, and if the flower experiences a total water loss, then you’ll not only taste the dryness, but you may have just wasted your money on quality cannabis.
There seems to be a few misconceptions about the optimal cannabis storage humidity range. Some claim that if the environment is over 15%, you’ll get mold. After many trials, we’ve discovered that the RH can get as high as 65% without the risk of any mold. The ideal range is 55% to 62% RH because this keeps the buds sticky and fluffy. The higher ratio of water vapor in the air slows the buds from evaporating its moisture content, so you can keep the RH at this level for months without losing the potency or flavor of your herbs.