It's getting late in the summer and that can only mean one thing ...
You'll read a lot of things on the Internet about when to harvest hops. I'm here to tell you that most of it is garbage. For all the precision and science that homebrewers but into making their beer, most seem content to rely on superstition and folk lore when it comes to gardening. Why? I have no idea, but let's go over some of the things you might have heard, why they aren't the best method, and the proper method for knowing when your hops are ready for harvest.
I see cones, that must mean they're ready to pick
This is the downfall of every first time hop grower. Much like the first batch or two of beer a homebrewer makes, first time growers of hops tend to be antsy. They fret and worry and ask the Internet "aretheyreadyyet?aretheyreadyyet?aretheyreadyyet?" without ever really listening to any advice given. Invariably, they will pick the cones too early and they'll lack the flavor and aroma they're supposed to have.
You should harvest cones when they feel papery to the touch
You might see this advice in conjunction with the springiness of the cone when compressed. Directions like these sound like new age, feel good mumbo jumbo. If you've never grown hops before, how are you supposed to know the difference between hydrated and dry cones? Since there's no switch on a hop bine, how are you supposed to know when "papery" is "papery enough"? Most hop cones are so light and airy to begin with, it's really hard to judge based on this touch alone. Given time and experience, you will get to know when to harvest based on certain signs like touch, but for the beginning hop grower, this is the worst advice.
You should harvest cones when are pungent and sticky when rubbed
As with the paper analogy, what does this mean exactly? It smells like hops? Since some hops produce a more resinous cone than others, how do you know the difference between not ready and a hop that isn't very resinous?
You should harvest cones when the lupulin glands turn cloudy
This is one of the few folksy methods that has a bit of truth to it. You'll notice the lupulin glands (located under the petals known as bracts near the base) start as tiny specs of yellow and grow as the hop cone matures. They'll go from clear to cloudy as this growth progresses. What happens if you don't check the cone regularly and know what a lupulin gland looks like as it develops? How will you know it's "cloudy enough"
I think you start to get the picture. None of the advice that's out there is based on objective measurements. They're all folk wisdom gleaned from hop farmers who have years of experience raising hops. You probably don't have that level of experience, so how can you objectively tell when hops are ready for harvest?
The objective way to know when to harvest
According to UVM and several other agricultural guides out there, hops are ready when they between 20-23% dry matter. What does that mean exactly? That's the percent of the hop cone that isn't water. So how do you do it? You can read the UVM link above, but scraping together 100 cones for a test isn't exactly feasible for homebrewers. I'll collect 5 - 10 cones from the area I'm looking to harvest in. Note that hops will tend to mature from the bottom up, so you have the luxury of harvesting your plant in stages as it reaches its peak if you so choose. You'll need to make sure the cones haven't been exposed to moisture such as rain or dew. I like to pick them late in the day when there hasn't been any rain for at least 3 days. Measure that sample on a very precise scale such as this or this or whatever you're currently using to measure your water salt additions. Write this number down exactly. Next you'll need to dry them out. If you have a food dehydrator, you can put the cones on there at the lowest setting and allow it to sit overnight. I don't have time for that, so I microwave the hops. It usually takes 2 - 3 minutes in my microwave at power level 5. You want to get them to the point where they look brown, like little pine cones. Watch them carefully though because you can reduce them to ash or even have them start to smoke and smolder. Once fully dry, remeasure the cones. The formula for percentage of dry matter is the dried weight over the fresh weight multiplied by 100%. If you're in target, great! Get to picking! If not, hops will gain 1-1.5% dry matter per week. Interpolate out how long you need to wait based on your initial measurements. Keep in mind that if it's exceptionally rainy or exceedingly dry, this can slow or hasten the hop development.
Ok, now you have a basket/bowl/bag whatever full of freshly picked hops. What do you do with them? If you're not going to use them immediately for a fresh hopped beer, you'll need to dry them out. If you're going to dry them, first weigh out your total harvest. We'll talk about why later. You'll see lots of complex instructions out there for building a hop oast which is really just a giant dehydrator. I say if you have a food dehydrator already and it can run relatively cool (140-150F or 60-66C) then use that. If you have a couple of window screens and a box fan, toss those hops out on the screen, point the fan at them, and use that. I personally like to keep the hops in a paper bag and keep them in the basement right next the the dehumidifier. I used to keep them up on top of the fridge for the same reason; a relatively low temperature, dry breeze will move around the bag consistently which will dry the hops quickly. I'll shake the bag once or twice daily and I'm usually all dry in 2 - 3 days. I even recall a brewer telling me he put all his hops in a pasta strainer (like the kind that inserts into a stock pot), opened up the service door on his HVAC unit and put it in right next to the filter. It dried the hops out in a day and made the whole house smell like hops. I can't say I advocate this method unless you live alone and really, really like hops but the point all of these methods are the same. You want lots of air flow, low temperatures, and not a lot of light.
How dry is dry enough? I personally aim for between 8-10% moisture content or 90-92% dry matter. Remember the dry matter measurement you made initially? That over the target dry matter percentage multiplied by your harvest weight will tell you the final dried weight of your harvest. For example, if you harvest 1 lbs of hops at 22% dry weight and want to get them down to 92% dry weight, that's (22/92)*1lbs = 0.23 lbs or about 3.8 oz. So weigh your harvest every couple of days until you get down to whatever your target weight is. What if you didn't do a dry weight calculation before harvest or you lost your measurement? Dry your hops out to between 20 and 25% their original harvest weight. Not as exact as what I would advocate, but it's a reasonably objective measure.
All the hops are dry and ready for storage. If you have a vacuum sealer, use it. A snorkeled sealer and mylar bags are the top choice option, but since that's fairly rare at the home level, a FoodSaver or any brand food vacuum sealer will work here. I tend to use extra thick bags to make sure the bag stays sealed. You'll notice as you're sucking the air out of the bag, the hops collapse and form weird shapes. If these shapes end up having a sharp edge or you vac around a twig or stem, it can cause a tiny hole in the bag and you'll lose your seal. That's why the extra thick bags are nice; it's a hedge against my mistakes. If you don't have a vacuum sealer, get some plastic freezer zip bags. Load the hops in, push out as much air as possible and seal them shut. However you get them packaged, the colder you can hold your hops, the better. The storage life of hops vary widely by variety, but I use the general rule of 2 years if held in the freezer and vacuum sealed.
Now that your hops have been used in a fresh hop beer or dried and stored away, what about the bine? You can cut the bine down immediately at harvest and pick off the cones much like a commercial hop farmer would. I've found it's less work to just pick the cones off as they come ready and leave the bines up. They'll eventually die back on their own and then take zero effort to clean up. In between harvest and death, those bines will continue to produce energy that will go down into the roots and be stored for the upcoming winter. If you're lucky, they'll even act as the supports a second flush of bines. I'd say about a third of the varieties I've grown will get a second flush and harvest out of them. My neo-mex strain (NEO1) is getting a third! flush this year. Every growth and bloom cycle has been extremely rapid on this plant, although smaller than an average harvest load. This is very unusual but it should serve as a lesson to just take care of your hops and let them do what they want to and they'll treat you right.
So now with my starter guide and fall maintenance guide, we should have your whole hop growing year covered! I hope to do some more hop related articles in the future including experiments on going all organic, Q&A (assuming I get some Qs), and some special home hop experiments if I can work a little magic on that front. I hope you've enjoyed reading this and find success in growing hops at home!
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