Short answer
A cannabis humidity pack is a small pouch that holds relative humidity inside a sealed container at a set level, usually 58% or 62%. One pack per jar, replaced every 2 to 4 months in normal use, keeps CBD flower and THC flower from drying to dust or climbing into mold territory. If the pack turns stiff or crunchy, the salts inside are spent and it is time for a new one.
What a humidity pack does
These packs are two-way regulators. They release moisture when the air in the jar is too dry and absorb moisture when it is too wet. That is the difference between a humidity pack and a piece of orange peel or a damp paper towel, which push humidity in one direction and invite mold. The pack holds the flower near its target water activity, which matters because water activity above 0.65 feeds mold and bacteria, while flower that drops below about 55% crumbles and burns hot. Terpenes stay intact longer at a stable humidity, so flavor, aroma, and vapor quality follow.
Prerequisites
- An airtight glass jar with a rubber gasket or a tight metal lid. Plastic bags and most tins leak.
- A hygrometer, if you want to verify the reading instead of trusting the pack.
- Fresh packs in the RH you want: 58% for dry-herb vaping, 62% for smoking, 55% or 69% for narrower preferences.
How to use a humidity pack
- Fill the jar no more than three-quarters full so air can move around the flower.
- Set one pack on top of the flower without burying it.
- Seal the lid and close it tight.
- Store the jar at 60-70 F in a dark cabinet, away from windows and appliances.
- Check the pack and the hygrometer after 24 hours.
- Wait 24 to 48 hours for the pack to pull dry flower back to the target range.
- Swap in a new pack when the old one turns firm or crisp, or every 2 to 4 months.
Do not open the jar for a quick smell more than needed. Each open costs humidity, and the pack has to work again to restore it.
Match pack size to jar
A 4 g pack covers about 7 g of flower in a small jar. An 8 g pack covers about 28 g. A 67 g pack covers bulk storage near 450 g. Undersized packs work harder and wear out sooner, so buy for the container volume rather than the amount you happen to have on hand.
Mistakes to avoid
- Sealing flower that is still wet. Packs control humidity; they do not fix a bad cure that trapped moisture in the stem.
- Using packs with concentrates or oils. They are made for plant material.
- Storing in a warm spot. Heat drives terpene loss faster than a few points of RH.
- Assuming one pack per jar lasts forever. Spent packs look fine on the outside.