It can't just be me – I come to use a particular jar of dried herb, spice or seasoning, to find it completely stuck together and impossible to get out. It's so frustrating, and seems to be worse with onion and garlic powder, which always seem to cake soon after the containers are opened.
This happens when moisture and humidity get into the container causing it to clump together and form a rock. Whilst the moisture will reduce the flavour and strength of the herbs, a lot of them you can re-invigorate by removing the moisture. Far less wasteful than throwing unused herbs and spices away.
How to remove the moisture
The easiest way is in the oven. I heat my oven to about 125C (250F) and use a metal skewer to get break the clump (or in this case garlic powder) out of the container, onto a sheet of baking paper, on a baking tray.
After just a couple of minutes, the heat will have removed the moisture, and I remove the tray and allow it to cool. Once cooled, I transfer it back into the container using a funnel and it now dispenses freely!
To prevent it happening again
Make sure the containers you store your dried herbs,spices and seasonings in are completely air-tight and always shut the lid/ close the container properly. Storing somewhere cool and dark (or even in the freezer!) will also help prevent moisture coming into contact with the inside of the container.
Avoid the temptation to shake the container directly into a pot of steaming food – this will allow moisture in. Spoon what you need out of the container, away from the stove top.
You can also add some dried beans or rice to the container to absorb any moisture and prevent the mixture from clumping.
Storing the containers upside down will also help prevent air getting in, making them last longer.