Nick Carr on August 26, 2020 0 Comments The dog days of summer are nearing an end. The mornings now begin to whisper of the coming seasonal change with just a hint of cooler air, quickly forgotten in the heat of the day. But, it’s there none-the-less and it’s nature’s reminder to homebrewers and commercial hop farmers alike: Harvest time is near. For places in the Northern Hemisphere, hop harvest falls somewhere between mid-August and the end of September. Many amateur hop gardeners have been watching those small coned jewels developing on their bines. Excitement and expectation mount, but suddenly you find yourself backed up against a series of questions. How do I know the optimum time to harvest? What’s the best way to harvest? What’s the best way to store them? Well, don’t get your hop bines twisted, this article will give you all the information you need and maybe more than you want. So, sit back and read on, my fellow hop wrangler, it’s time to harvest. When Is It Time To Harvest? So, your bines are drooping under a heavy load of coned goodness. But, how do you know when the cones are ripe? It’s a question every homebrewer gone hop grower must face. It’s easy to get excited and harvest too early, but you’ll be doing yourself, your hops, and your beer a disservice if you jump the gun here. Better to harvest late, than harvest early. Early harvesting means the hops were unable to reach their full alpha-acid potential. It can also adversely affect both the present season’s and the next season’s yield because it can disrupt the reserves of carbohydrates in the roots. If this is your first year harvest, expect a small one; just enough to maybe augment your next 5-gallon batch or drop in a special, smaller one gallon “homegrown” batch. The second year, after the root has established, will be better, and the following years even better. Checking for cone ripeness isn’t hard, so the travesty of picking early really shouldn’t be as common as it is among home hop growers. At any rate, let’s make sure it doesn’t happen to you. The most accurate way to test ripeness is to test the cones dryness. Most hop varieties are ready to harvest when they have reached about 23% dry matter. To test this: Take a sample of your hops. Pick a day when it hasn’t rained in a couple of days and harvest the sample after the dew has burned off. If you have several hop plants of the same variety be sure to sample across all the plants, taking from the upper parts of the bine. Weight this sample on an accurate scale that can read less than a gram. Write this weight down. Now you want to dry the sample out completely. To do this you can use a food dehydrator, a conventional oven, or even a microwave though in this article MSU doesn’t recommend using a microwave, saying the sample is too small to absorb all of the wave output and can damage the microwave. The food dehydrator will likely take at least 24 hours to dry the sample out. The oven and microwave will do it faster, but you will have to monitor your hops more to avoid burning them. Every-so-often take the hops out and re-weigh them. You should see a constant drop in weight. Once the weight levels out and hasn’t changed for two-three weigh-ins, they are at zero moisture. At this point record the weight and divide this number by your original weight. This is your dry matter percentage (I write out an example of this calculation in the “Drying” section). If the number is within one or two points of 23% you’re safe harvesting. If not, you can at least estimate when the hops will be ready. Hops lose 1% dry matter anywhere from 4 to 7 days (the UVM reference gives a chart for several varieties) so depending on what your test found you can work out approximately when your hops will be close to ripe. This may be the most accurate way to know when to pick, but it’s not the only way. You can also look for a certain set of characteristics in your hops. These characteristics can be slightly ambiguous and hard to recognize, especially for the inexperienced hop gardener. But, closely monitoring your crop and even testing for these characteristics a couple of times before you enter the harvesting window will go a long way in helping you recognize the character change when they are ripe. When To Harvest Ready Not Ready Visual Small leaves of the cone appear to be opening and leaves at the base of the stem are beginning to dry and possibly turn brown; bright yellow lupulin should be easily visible around stem and inside cone Cones appear closed and tight; no signs of lupulin (orange lupulin generally means you’re late) Touch Cone is springy, returning to its original shape after being compressed; dry, Papery, light, slightly sticky Cone doesn’t immediately return to its original shape, instead remaining compressed; compact, soft, damp-feeling Aroma Expected hop fragrance. A mix of: (pungent/pine/onion/grass) If they smell vegetal or “green” Hear Holding the cone to the ear and rolling or lightly shaking should result in cricket-like rustling No sound If you want to be sure you’re getting the hops at the optimal time the dry matter calculation is really the only way to go. But, if the hops adhere to the above characteristics you can be reasonably sure they are within the harvest window. How Do I Harvest My Hops? Now that you’re confident your hops are ready, it’s time to get to harvesting! There are two ways to harvest your newly ripened hops: harvest by hand in place, or cut the bine down and then harvest the cones. Harvesting in place is recommended for first year crops and if you happen to have wild hops you’re foraging. Not cutting the bine ensures important nutrients flow back into the young root before winter sets in. The second season and onwards you can either pick the hops in place or for easier harvesting, cut the bine a couple feet above the ground. This way you don’t have to spend any time on ladders. You can just sit in a chair or on the ground and work your way down each bine, striping cones. Once you’ve finished picking you can compost the bines or turn them into hop wreaths. Safety Tip: Hop plants have little hooked hairs which can cause irritation, so be sure to wear long sleeves, gloves, and even goggles when you are picking…. at least until you know if you are affected. Generally a healthy, well cared for, mature hop plant should yield on average 1 to 2 pounds of dried hop cones, per season. Ok, I’ve Picked My Hops, Now What? You’re probably sitting, drinking a homebrew, admiring your bountiful harvest, and wondering how best to process this newfound wealth. Unless you have a wet-hopped brew on your mind, it’s time to do some drying. Once picked, your hops’ freshness clock is ticking. Time, moisture, heat, and light all play a role in the quality of hops you’ll end up with. Processing them is a matter of removing the right amount of moisture in the least time possible while limiting the hops’ exposure to light and heat. The quicker you can get them dried, bagged, and into cold storage the better. So, finish that beer and let’s get to it… Harvested hops contain anywhere from 75 to 85 percent moisture and most of that needs to be removed to avoid spoilage. On average hops are dried down to between 8 and 10 percent moisture before being stored. There are three different methods for drying your hops; air, food dehydrator, or conventional oven. Air Drying Air drying is really the only good way to dry hops. Remember the comment about heat being a deciding factor on the quality of the finished hop? Air drying in all its forms dries at the lowest temperatures possible, making it the least destructive. There is the balancing factor of time to consider too. You can simply place your hops loosely in a paper bag(s), or on a window screen if you have the room. Put them somewhere with good air circulation, such as an attic, and wait. This method takes care of the light and heat factors, but not the time. It can take up to a week or longer and optimally you want to be done within three days of harvest. Another option is to put them on some kind of sheet, screen, or in a paper bag and place them outside. But this obviously won’t work for everyone because you want dry, hot conditions. Also, you have to contend with the light factor (not as much if you use a paper bag) and it may not speed up the drying process to a large enough degree. A third, and better, air-drying option is using a box fan to constantly blow air across your loosely laid hops. To use this you’ll have to build a hop oast. An oast is basically wooden framed screens used to lay hops on and then air is circulated through the hops. There are a few different ways to construct an oast, but the simplest is to build individual framed screens from 1 x 2 or 2 x 4 lumber and galvanized window screening. Then place these screens on top of each other and place those on top of a box fan laid on the ground. Elevate the fan with another couple 2 x 4 pieces so that there is good airflow underneath. It’s sort of like constructing a tower; first comes the 2 x 4 pieces, then the fan (pushing air upwards), then the boxed frames with your hops. You’ll have to decide for yourself if building an oast of any type is worth it based on the size of your harvest and how much you like DIYing. You could also place your hops between air filters strapped to a box fan as The Mad Fermentationist outlines. Dehydrator The higher the heat and the longer they are exposed to heat, the more aromatics will be lost. Thus, limiting the heat factor as much as possible is especially important for aroma varieties. Air drying really is your best option. In fact, I’d hazard a guess and say that more time air drying is less detrimental than drying them quicker at a higher heat (though I’ve read posts from a few homebrewers that would disagree). That being said, there’s always the possibility that air drying just isn’t a possible option for you. In such a case you can use a food dehydrator or conventional oven. The dehydrator is probably a slightly better option because you have better and lower temperature control. Simply set your dehydrator between 120 and 140oF and put your hops in it. The higher range can dry them in 9 or so hours, the lower range will take longer, but again you’re losing less fragile aromatic compounds. It’s a trade-off. Oven An oven can be used, but it’s probably the worst option. The higher heat (most ovens have a low setting somewhere around 150oF) makes it easy to over dry hops, even scorch them. If you do use an oven watch your hops like a hawk. Even removing them every few minutes to avoid any scorching can be a good idea. Expect them to be done relatively quickly. How Do I Know When The Hops Are Dry Enough? To know when your hops are at that desired 8 to 10 percent moisture we have to go back to the dry matter test we first used to test hop ripeness. If you dry a sample to 0 percent water, you know the amount of moisture in the “wet” hop. Once you have what percentage of the hop was water we can calculate what the target weight, with the desired moisture content, should be. So, say we have a test sample of around 2 ounces (57 grams). We dry it, checking the weight once-in-a-while; the weight stabilizes at 14 grams. To find out moisture content, we use this calculation: [1-(dried weight/wet weight)] x 100= percent moisture Sticking our weights in, we get: [1 – (14/57)] x 100 = 75 percent moisture So, for this sample, a target weight at 10% moisture would look like: dry weight / [1 – (percent moisture desired/100)] = the targeted weight Using our dry weight we get: 14 g / [1 – (10/100)] =15.5 grams at 10% moisture You may want to do the dry matter sample test for each hop variety if you’re harvesting more than one type. Hop varieties can dry out at different rates. But, if you’re only dealing with one variety it’s safe to assume all of the harvested hops have the same moisture content. Once you know the dry matter percentage of your sample you can calculate the target weight of any amount of hops at your target moisture. In our example, we harvested the hops at 25% dry matter (or 75% moisture) and want to get them down to a dry matter content of 90% (or 10% moisture). So, if we had, say, another pound (453 grams) to dry, we can use calculation taken from the University of Vermont paper referenced above: (% Dry Matter Harvested Hops / Targeted % Dry Matter) x Hop Amount = Weight at Targeted Moisture (.25 / .90) x 453 g = 125.8 grams at 10% moisture This is the most accurate way, but to do this you need enough hops to “waste” some on the dry matter test. And I’ll say it again…you also should have an accurate scale that can measure less than a gram. If you are harvesting just a small quantity and don’t want to give any up to the dry matter test you’ll have to be content with fewer scientific tests. You can check certain characteristics as they dry to estimate when they’ve reached the right dry matter content. Stem break: try breaking a stem. If the stem bends and doesn’t easily snap in half they need to dry longer. Lupulin: If you open up a cone and the lupulin is powdery, falling out easily and the inside is mostly dry with maybe just some slight stickiness still, then they are about done. I realize these can both be pretty subjective, but do the best you can. Improperly dried cones can mold in storage, so if you’re not sure, it’s best to err on the side of caution and go a little longer. Better to have slightly inferior hops you can use, than a wilted rancid unusable mess. My Hops Are Dry, How Do I Store Them? Once the hops are dry packaging and storage are pretty straight forward. Weigh your hops out and separate them into 1-ounce piles. Separating them into smaller packages will make it easy to defrost and use only what you need. Now put each ounce in freezer-safe Ziploc bags. You want to get as much of the air out of them as possible so break out that vacuum seal if you’ve got it. If not, try to push as much air out of the bag as possible. This, of course, will mean crushing the hops, but better to have crushed hops than a bunch of oxygen breaking your hops down. Once done mark the weight and hop variety on each bag and stick them in your freezer. You’re done harvesting and processing your very own hops. What to do now? Maybe just pull one of those bags back out and brew something! Happy Harvesting!