Micro hop plucker/stripper
Monday, September 17th, 2018
The need
You may have noticed that I am a bit obsessed with hops. Currently, I am running three small yards for our experimental hop breeding program. Hops are wonderful to grow, but can be a real pain to pick. Hand picking takes about 1 hour per plant – meanwhile, picking machines cost hundreds-of-thousands of dollars and can typically be as big as a warehouse. There are a few “smaller” machines on the market, but the size and cost is still prohibitive for the hobby grower.
- Reference: Hops harvesting “what’s out there” by UVM
The build
Picking fingers
The core of any hop harvesting machine is the picking fingers. These metal loops are used to grab on to the hops cones and pop them off. They need to be strong, flexible, strongly attached, and have to correct angle. I practiced making some of my own – but, due to time constrains, opted to purchase some from Sea to Sky hop solutions.
These are replacement fingers for the Wolf 140/170 picking machine. 56 fingers was enough to cover 4 picking bars about 30″ long.
Spindle
To hold the fingers, I simply created a spindal with 4 bars created from cheap 2×2 lumber. These are spaced around the metal shaft with 8″ plywood circles and a few more 2x2s. Super simple and cheap, but more than strong enough for a picker this size.
Just be sure to chamfer the edges of the 2x2s to mount the picking fingers … before you put the spindle together.
Box
The spindle is mounted inside a 30×36″ box using inexpensive pillow bearings. The box needs to be ridged and heavy enough to keep from moving when you pull the heavy hop bines through.
The box is also important as it keeps your hop cones from flying across the yard when they are plucked. Originally my box was open, but I quickly added a hinged lid with neoprene “car wash style” flaps. This looks a bit funny, but effectively keeps most of the cones contained.
Power
For power, I used a simple 1750rpm, 120v motor. This needs to be slowed down significantly for the spindle to run safely. A 15″ pulley slows the speed down to a reasonable 175rpm (about 3 rotations per second).
As a basic safety measure, I hooked the motor up to a cheap dead-man switch. This way it only runs when your foot is on the pedal.
Sorting
The machine only strips the hops. Sorting done separately, but isn’t difficult. We simply poured the hop/leaf mixture in front of a box fan – this blow away about 80% of the leaves.
Success?
The hop stripper reduced the harvest time for the Barber hop yard to 10% of last years effort – half a day and the whole yard was down, stripped, sorted, and ready to dry.
Pros
- Stripping the cones works extremely well (much better than expected)
- Very stable – no need for extra weight
- Safer than expected. Does not grab fingers. Dead-man switch stops it quickly.
Cons
- Sorting cones from leaves needs to be improved
- It will sometimes grab tangled bines (especially near the ends)
- Small, but still bigger than I wish (pain to store the 364 days its not in use)
Ideas for the next version (Mark II)?
- Do we even need the heavy box?
- Idea: a simple spindle and guards mounted above the bed of a pickup truck
- Would be ultra stable and portable
Steve Hogath Says:
I have a small hop yard that requires a micro picker such as yours. Would you have plans available for your picker to aid me in my building of a picker. Any help would be greatly appreciated
Thanks steve
nagmay Says:
Steve,
Sorry, I don’t have any plans at this time.
Just made it up as I went along, but the pics should give you a good place to start. The most important aspect is to keep the speed down (<200rmp) and have some basic safety items like the dead-man pedal.
nagmay Says:
To be honest, I will probably re engineer the thing before the next harvest.
As mentioned, mounting the spindle on a truck bed would give it much more stability and make it super portable.
Let me know if you have any specific questions. How big is your hop yard?
Frank_Z Says:
Hi Gabiel,
great idea, especially with buying/using original picking fingers.
My hop yard is about the same size as yours, I just wonder how well it works with mature plants/tangled bines (up to 10# of hops on one plant with one string per plant and with single leafs up to almost a foot in width).
If it works well it will save me days.
Thanks
Frank
nagmay Says:
Frank,
With the size of this build, the tangled tops are more difficult. Our trellis is < 20', so we get that issue. I cut the tops into sections to more easily feed them through. However, it was still much faster than picking by hand. That said, adding more fingers, or a 2nd spindle could really help.
Mark Says:
I see you used flange bearings for the metal rod to turn in, but how did you attach the 8 inch discs that hold the picking finger barrel to the metal rod to prevent slip and slide issues?
nagmay Says:
Mark,
Behind the disc ends, there are simple 2×2 cross braces. On each end, I drilled through one of the braces, rod, and out the other side. A small bolt then holds it all in place.
There are better solutions, but it hasn’t slipped yet.
Victor Shaffer Says:
For your picking fingers, how many sets do you have on the spindle? Also, did you buy the picker bar complete or just the fingers and then attach them to your spindle? I appreciate you posting this online – very helpful for small growers.
nagmay Says:
Victor,
For this short machine (4’wide), I needed 56 picking fingers, that’s 14 per bar.
The bars are completely home-made. They are just fir 2×2’s with the corners shaved off. Makes for a perfect fit. I then used a simple metal strap and screws to hold them on.
George Lean Says:
Outstanding job on box. If possible, please call me.
George 706-593-6282
Tabby Says:
Very, very cool!
Jim Spencer Says:
Do have these for sale?
nagmay Says:
Jim,
No – this is more of a diy project.However, if there is continued demand, I would consider putting together some blueprints and part lists.
Konstantin Konstantinov Says:
Can you share the scheme?
John S Says:
Hi
I just started my second year of hopyard and will need to start thinking about harvesting. I am wondering if I could get more specific pics on your build?
What horsepower motor are you using?
Have you put in the second stripping spindle.?
Thanks John
nagmay Says:
John,
How many plants do you have? Hand picking works great, and is probably the best option until you have over a dozen plants to pick. On the other hand, a full size yard with hundreds of plants will need something quite bigger.
I don’t have specific plans for this, as it was cobbled together quickly. If I get around to upgrading this year, I will be sure to take better notes.
The motor is quite small (1/3hp), but slowing the spindle down to 180rmp results in more than enough torque.
As for a 2nd spindle, it would absolutely speed up the picking process, but would also complicate the build.
John Says:
I have 200+ plants In this year. 7 from last year.
I’m thinking a double spindle would be best. I don’t have a budget for a bigger bought harvester. I’m hoping the small micro breweries buy what I have. There are plenty of them around. I may plant a few more fugal hops next year just to even the plantings.
Ke ep me in mind when you start your modifications. I’m considering adding a screen and blower to help sort.
Thanks again for your help
John
John Eugene Says:
Hello Gabriel,
This machine you created seems like something I’d like to build! I had only one question if I may. Since you mentioned that you used 56 picking fingers on 4 2×2 bars while the are sold 28 hands attached all together, I’m wondering you simply cut them to have your 30″ length? Also, do you think that over 30″ of length could be useful?
I have 600 plants, I guess I may then build one a little longer than 30″ perhaps.
Amazing stuff and this sharing is very generous! Congrats to you for doing this.
Jean
nagmay Says:
Jean,
Glad this was helpful. If you look closely, you’ll notice that the picking fingers are individual pieces that can be easily disconnected – no cutting needed! You can rearrange to the fingers to make any length you need.
As for the length, that all depends on how you want to process the bines. With this size, I find it easy enough to cut the bines into sections and pull each through, rotating 180 degrees to get all the sides.
A larger machine (and/or) a 2nd spindle should make it possible to pull an entire plant through in one go.
I’d love to see what you come up with.
Bill St. Arnaud Says:
Just finished hand picking my hops this year and I realize I will need a small mechanical harvester like yours for next year before I run out of friends and volunteers!
You mention that you are working version 2. Any details?
Bill
Gene Tonne Says:
Thanks for providing your hop picker phones.
I am also like Bill St. Arnaud and finished picking 100 lbs my hand. Doubled the plant count this year.
I am going to build a mechanic picker / sorter over the winter.
I would like your thought if you do not mind.
I am limited on space, What would your thoughts be on a narrower version 7-10 fingers wide vs. the 14 with a second drum?
Mechanically pulling the bines thru the drums with a hand operated two rubber roller system.
TIA
Gene Tonne
TCF Hops
Southern MN 42 latitude
Powell Butte Hop Farm Says:
In the process of building a double shafted micro hop picker. Purchased the hop fingers and electrical motor w deadman switch. Will keep you updated on the progress. Thank you for the pics and comments to get me this far…
David Says:
@Powell Butte Hop Farm, how did you go?
Powell Butte Hop Farm Says:
It is harvest time this week. I’ve been fine tuning and it looks like it may do the job. Will post more later
Steve Says:
Hi Gabriel,
I think you’re in Portland like me. It would be great to connect when you see this. This is my second year growing, and I lost access to the Wolf harvester I’ve been using the past two weeks. I have about 680 bines to go. Any chance your machine is available? I also saw from the Homebrew Talk forum that you tried a hop rake…how was it?
nagmay Says:
Steve,
Nice to meet a fellow hop enthusiast in Portland!
Unfortunately, the stripper is already packed up and in storage for the year.
In any case, you may be underestimating how small the stripper is, and how much manual labor goes into the operation (not to mention the lack of safety features).
I can run through about 50 bines in a day. For your size of harvest, something much bigger is required.
Powell Butte Hop Farm Says:
So I built the hop picker/stripper as planned and ran bines thru for the annual harvest of 2022. It works exceptionally well for removing the hops off the bine. A slight rotation of the bine to cover all.
So a huge checkmark for success of this process. The next process is sorting, as there is lots of leaf material that gets stripped. So back to the drawing board for building a hop sorter for 2024. Btw…we hand picked this years hops. 2 days and about 30 people…????
nagmay Says:
Powell Butte,
Would love to see what you built!
My design also strips lots of leaf material, but this seems to be the case on commercial strippers as well. To my understanding, there needs to be a 2nd sorting step.
In commercial rigs, they often have an angled screen/fan combo that sucks the leaves in while allowing the hops to roll down.
I have found pouring the mix in front of a box fan works well. Most leaves are tossed away while the hops fall straight down. This gets rid of about 90% of the leaf material.
Powell Butte Hop Farm Says:
That is my plan as well to build a sorter and incorporate it next to or beside the picker. Unistrut material. Chains. Sprockets. Conveyors. Etc. Just need the time this winter