Hop cultivations in Japan and elsewhere are usually conducted by contract system between beer company and grower. Harvesting Hops are usually picked by hand. Hops collected in September when they are ripe, carefully dried by artificial heat and packed in bags or bales. From bloom to harvest requires about 40 days. Sometimes hops are treated with sulfur dioxide to improve the color and prevent change of active principle.
Hops deteriorate upon aging and exposure to atmosphere.
Kiln-drying is practiced in some humid areas. Yields and Economics Yields vary according to locality, climatic conditions, and variety. Hops are grown in mnay other countries also. United States imports about 6 million kg, mostly from Europe for different flavors. A growing amount is being marketed in extract form.