Letting a blend rest

A blend tasted immediately after mixing and the same blend tasted a week later are not the same product. Whether you build that into the process or discover it through customer feedback is up to you.

Two things happen while it sits

One is physical and well documented. One is sensory and mostly reported by practice. They work in opposite directions, which is why resting has an optimum rather than being simply good.

Moisture equalizes

Components enter a blend at different moisture contents. Sealed together, they equilibrate: the wetter material gives up water to the drier one until the batch settles at an average.

That is usually helpful, because it removes the local damp spots where caking and spoilage begin. It is unhelpful if the average is too high, in which case resting has distributed a problem rather than solved it. A blend that cakes uniformly a week after mixing was a blend with a wet component.

Aroma marries, and it is not folklore

Volatile compounds migrate between particles in a sealed container. The sharp edges of a freshly mixed blend soften and the result reads as more integrated. Practitioners describe this consistently; it is not something published specifications measure.

Against that, resting is time, and time is the mechanism by which ground spice loses volatile oil. So you are trading integration against strength, and past some point you are simply storing a finished product.

How long, and where

Days rather than weeks. Sealed, cool and dark, in the same conditions you would hold any ground stock, because the blend is now the most perishable thing you own.

Then taste it against the previous batch before it goes into jars, not after. The rest period is the last point at which a correction is cheap.

References