Two of the most commonly used types of hops in craft beer are Pellet and Leaf Hop, both of which have similar storage requirements.
Hop storage needs to take into account five conditions: oxygen, temperature, light, moisture, and biology.
Oxygen is the primary enemy of Hops.
The oxidation of high molecular polyphenols in hop polyphenols will give beer a harsh bitter taste. The oxidation of the aroma compounds in the hops will lead to the loss or alteration of the aroma characteristics of the hops, but sometimes the oxidized hops will have a relatively noticeable ester fragrance.
Brewhouse storage method
Currently, hops that can be purchased in large quantities are usually packed in 5kg/bag, and it is difficult to use up the domestic ready-made units in a short time. It is recommended to divide the hops into N small packages immediately after receiving them and take one bag at a time.
Oxidized Hops
Can be added in small amounts at the end of the boil as an aroma in wheat brews.
Nitrogen-filled packaging
There is a large amount of nitrogen in the aluminum foil bag, and there is no adhesion between the hop particles, which is convenient to use and is currently the most widely used packaging type.
Temperature
The recommended storage temperature for hops is not exceeding 4 °C. Above this temperature, alpha acid begins to degrade significantly and polymerizes to form gamma resin, which produces a bitter taste and affects the quality of hops. There is no lower limit required. Low temperature helps preserve the original quality of hops. When the temperature is below 0 °C, the shelf life can be up to 5 years.
Other: Damage to imported hops caused by high temperature often occurs during transportation. In summer and autumn, the country is usually high in temperature, and express delivery takes 2-3 days, which will have a significant impact on hops.
The disadvantage of freezing much below 0 °C is the change in hop morphology. The hop particles themselves contain about 8% moisture.
It is recommended that the lower temperature fanatic divide the hops into small packages to avoid the particles in the large bag from breaking and oxidizing when the hops are taken.
Lights
Lights will cause the color of the hops to turn gray and white, and the aroma components will be lost in large amounts. All hops are currently packed in aluminum foil bags.
Moisture
In the hop storage environment, the relative humidity should not exceed 60%. Excessive moisture can cause:
Alpha acid to polymerize and form gamma resin, resulting in post-bitter taste;
Mold bacteria, hops can kill most gram-positive bacteria and have almost no killing effect on gram-negative bacteria and fungi;
Rot, plant cells in an environment with sufficient water, rot is inevitable.
