FactorDoWhy
ContainerAirtight jars or tinsAir stales spices and fades aroma
PlaceCool, dark drawer/cupboard, not over the stoveHeat and light drive off the flavour oils
MoistureDon't shake over a steaming potSteam clumps spice and invites mould
FreshnessWhole lasts years, ground 1–2; label & dateBuy what you'll use; replace when it's faint