Herb drying is the controlled removal of moisture from aromatic plants to a stable water activity while preserving essential oils, colour and aroma, producing shelf-stable ingredients for food manufacturing and seasoning applications.
In trade practice
Herbs are dried whole or in cut form at moderate temperatures with adequate air circulation to limit essential oil loss; higher temperatures shorten drying time but degrade volatile compounds. After drying, material is cleaned, sieved to the specified cut size and checked for stem content, foreign matter and microbiology before packing. Buyers should request essential oil content data alongside standard moisture and microbiological certificates, as essential oil percentage is a key quality indicator for culinary herbs. Common mistakes include over-drying, which causes colour loss, and under-drying, which risks mould during storage.
In a specification
A herb specification typically states drying method, maximum moisture content, maximum water activity, minimum essential oil content, cut size or sieve grade, maximum stem percentage and microbiological limits.