Hop components (such as alpha acids and essential oils) undergo changes as soon as they are harvested. The rate of loss is dependent in part on storage conditions, and on the variety, and condition of the hops when baled. For example, alpha-acid stability is expressed as the percentage of alpha-acids remaining in baled leaf hops after six months of storage at ambient temperature.
Although hops deteriorate with storage, the aging process can be slowed with refrigeration, anaerobic packaging, and minimizing contact with light. Of these three, refrigeration is the most important, followed by anaerobic packaging. For optimum preservation, hops should be stored at temperatures between 0 and 2°C.
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