Capers are the flower buds of a thorny shrub that grows around the Mediterranean region.
Capers are hand-picked between April and August, before they flower. They have been used as a seasoning or garnish since the 16th century, pickled in vinegar in wine-producing countries, or in brine in countries where salt was not heavily taxed.
National preferences regarding caper buds illustrate the differences in taste between different cultures. The French prefer "non-pareil" capers: small, pickled in vinegar, crispy and tart. The Italians, on the other hand, prefer capers that have been picked closer to flowering and pickled in brine: they have a more floral and slightly bitter flavour.

A Gourmet's notebook