Storing cannabis: keep it fresh and potent

Cannabis degrades over time, but how you store it makes the difference between flower that’s good for months and flower that’s harsh and weak in weeks.

The four enemies

• Light: UV breaks down cannabinoids fastest. Store in the dark.
• Heat: warmth dries out flower and degrades potency. Keep it cool, not hot.
• Air: oxygen degrades THC over time. Limit air exposure.
• Humidity: too damp invites mould; too dry makes it harsh. Aim for a stable middle.

How to store it well

1. Use an airtight glass container (a sealed jar), not a plastic bag, which builds static and lets air in.
2. Keep it in a cool, dark place, a cupboard, say, not a sunny windowsill or the fridge.
3. Add a humidity-control pack set to 55 to 62% to hold the right moisture level. This is the same trick that can gently revive slightly dry flower over a day or two.
4. Keep different strains in separate jars to preserve their aroma.

How long it keeps

• Flower: best within about six months, though it stays usable longer while slowly losing aroma and potency.
• Edibles: follow the printed best-before date, like any food.
• Concentrates and oils: generally stable for a year or more when kept cool and sealed.

When it’s gone off

Toss flower if you see fuzzy white or grey growth or smell ammonia or mustiness, which point to mould, or if it has dried to a harsh, crumbly powder that offers little aroma. Mould in particular is not worth the risk.

What not to do

Don’t freeze flower (it makes trichomes brittle), don’t leave it in a hot car, and don’t store it loose where light and air get to it.

Sources

• Health Canada, Cannabis storage and safety