Harvesting Hops
If you brew your own beer, having the opportunity to harvest your own hops is usually quite a treat. Hop cones usually ripen sometime in late summer to early autumn. They are ready to be harvested once they feel papery, spring back when squeezed, and have a strong aroma. The yellow lupulin powder on the inside are indicative that they are ready to be harvested as well.
When you pick the hops, wear gloves to protect your skin from irritation from the tiny hooks in the hop bines that help them climb. Remove any leaves or stems, and place the hops in an open container while you’re collecting. Shake off any bugs, be sure to give them time to escape, and do not wash the hops!
What you are picking are termed “wet” hops, as they are freshly picked and undried. These can be used straight away to make green hop beer, which I will not go into here. Any wet hops not immediately used should be dried as soon as possible. Hops are around 80% water and drying prevents mold and degradation in storage.
Drying Hops
Ideally, you want to dry hops at the lowest temperature possible to preserve the aromas. Target moisture for storage is ideally 8-10% moisture. To ultimately find the percent moisture of the dried hops, you will need to know the percent moisture of the hops that were just harvested. So, prior to drying the entire harvest, you will need to determine the amount of moisture in the wet hops. There are two ways to do this, either:
- assume the percent of moisture (80% is often a good assumption), or
- measure the percent of moisture with a small sample of the hops. If you don’t have a lot of hops, you may not want to waste any by testing moisture content.
If you go for option #2, you will need to weigh a small sample of hops before and after they have been totally dehydrated. To totally dehydrate a small sample of hops, you can either use a food dehydrator (best) or an oven. If you use an oven, do not set the temperature so high that you toast the hops! If you weigh the sample twice with a couple of hours apart and there is no change in weight, you’re likely at 0% moisture.
Once you’ve either assumed or measured the moisture in the wet hops, you’re ready to proceed drying the remaining hop harvest. How quickly hops dry depend upon temperature, humidity, air circulation, and surface area of hops. There are three common methods of drying hops:
- Air Dry – This method preserves more of the hops aromas, but takes the most space and the longest time. Spread the hops out in a single layer on a screen in a warm, dry, well-ventilated area without direct sunlight. Turn them occasionally. This takes 2-5 days, depending on humidity and temperature.
- Food Dehydrator – If you have a food dehydrator, set it to 35-40°C (95-105°F) and spread the hops on the trays. This is the most temperature precise method and can often be done overnight.
- Oven Dry – This is the quickest, but you need to keep an eye on the temperature. Set your oven to a low temperature of 40-55°C (105-130°F). Place the hops on baking sheets in a single layer (see the picture below) and leave the door slightly ajar for airflow. Be sure to check frequently and turn them occasionally. Use a thermometer to ensure the temperature doesn’t go over 60°C (140°F), or you’ll cook away the aromatic oils. This will take anywhere from 2-6 hours.
The hops are likely ready when they’re a bit brittle and break apart easily. The inner stem (called a strig) should break instead of bend. Weigh them and plug the numbers into the calculator above to see if you’re in the 8-10% moisture range before storing.
Storing Hops
Once the hops are dry, pack them in airtight containers, or better yet vacuum-sealed bags if that’s an option. If you are going to use the dried hops within a month, store them in a cool, dark place at room temperature. If you are not going to use the dried hops anytime soon, freeze them to maintain freshness for many months.
