When to harvest your hops is a tricky topic and most commercial farmers have their own special ways to determine when to harvest. In general each variety has its own harvest window; Centennial tends to be one of the first to ripen and depending on the growing season they can be ready towards the end of August. But the majority of varieties peak around the second or third week of September and very few are still in the ground come October. Not only does the variety determine when it is best to harvest, but it also determines how long you have to harvest. This is commonly referred to as the harvest window and some varieties like Columbus have a notoriously short harvest window that only lasts a day or two.
The most important thing to look at to determine proper harvest date is the lupulin glands. The lupulin glands run along the middle of the hop cone and vary from light yellow to brown in color depending on maturity. Ideally, hops will be picked when the lupulin glands are fully matured (bright orange) and not overly ripe as they will tend to have unpleasant aromas of onion and garlic if left to hang too long. Starting in the beginning of August you can start pulling off a couple cones, cut them in half with a razor blade and watch the color, shape, and aroma change even day to day. If you have access to a microscope that will give you an even better idea of the ripeness of the lupulin glands as they will start out perfectly round, but start looking more like a raindrop as they ripen.
Some seasoned farmers squeeze the cones and are able to tell maturity based on feel. The young cones will feel waxy and squishy, while mature cones will feel more papery and springy. The most important thing to keep in mind for harvesting is that if you like the way it smells, then you will probably still like it after you brew with it. Keep track from year to year on when you harvest and it will help you to really dial in the ideal harvest date.
When it is time for you harvest, it is important to dress appropriately by not having exposed skin on your arms. Bines can be a bit mean and are notorious for cutting or scraping skin. Eye protection and leather gloves are also a good idea when harvesting. Depending on your growing setup, hack the hops just above the ground and cut the tops from the wire so you can lay the bine down on a table or the ground. It will take awhile to pick all the cones by hand, but the only other alternative is to put in a million dollar picker, which your neighbors might not like too much.
Once the cones are all picked you can brew with them wet, but you must use them within 24 hours or you risk them getting slimy as they start to decompose. If you are not able to use them immediately you are able to dry them out and then store them in the freezer. Commercial kilns use high powered heaters and fans to achieve the goal of less than 10% moisture by weight. And even then it still takes 6-8 hours to properly dry them out. At home, spread the cones out on a screen or breathable fabric so that fans can blow air both under and over the layer. Airflow and temperature can be increased to decrease drying time, but it will still probably take at least 6 hours and be sure to toss or mix up the cones so they dry out evenly. Food dehydrators are also an option, but tend to not dry many hops at once. Once the cones are properly dried it is best to vacuum seal them before tossing them in the freezer.
Hops do not require any care or maintenance over the winter as long as they are cut down to the ground.
Happy growing and brewing everyone! Be sure to tell us about your growing and harvest experience on social, #yakimavalleyhops