The Garagiste’s Destemmer - Homebuilt · PDF fileNext stop was the hardwood lumber yard. The main destemmer shaft would be made from a full 2” x 2” x 36” long piece of maple,

The Garagiste’s DestemmerBy Steve Hughes

© Steve Hughes, 2011

After years of removing stems from crushed grape clusters by raking them over a metal grating (quite successfully, I might add) I set out last summer to build a powered crusher and destemmer. I spent lots of time watching some of my commercial winemaker friends using theirs, and carefully examined how some of the crushers at the local home brew shops were designed. I found a number of technical drawings of some of the imported machines and finally decided I could do that with my fairly basic home shop equipment.

I started out with what I felt would be the more difficult piece of equipment, the destemmer. Then I’d build the crusher to fit it after confirming the destemmer worked as hoped. The goals for the contraption were five-fold:

Project Goals and Plans

1. It had to be based on wood and other materials that can be fabricated with the wood working equipment that I had in my home shop.

2. The whole crusher, destemmer and stand had to be portable, and be able to be quickly disassembled and stored on a shelf or two in my garage winery, preferably in the 14” of space above my Barrel Room (see WineMaker June-July, 2010 issue).

3. Crushing and destemming would need to be gentle on the grapes, with a percentage of the berries not getting mushed or crushed.

4. It needed to be easy to clean up after a long day of crushing.

5. And it had to cost a fraction of the price of a comparable powered crusher destemmer.

Going on a Shopping Excursion

I decided that the design would be based on the typical destemmer that would spin a shaft with helically spaced “fingers” that rubbed the crushed clusters across a screen with holes so the berries would fall through the mesh and the fibrous stems would continue over the mesh and fall into a waiting receptacle. The mesh basket posed the first challenge; I looked at sheet stainless steel, but it would be very difficult to work with and would blow a huge hole in my budget. I stopped by my local plastics supplier and explained what I needed to make. They recommended I try using sheet HDPE (high density polyethylene) which is rated safe for food contact, flexible, easy to work with regular tools and virtually indestructible. They handed me several different thicknesses to consider and I guessed that the ⅛” sheet would be just what the doctor ordered.

I also picked up a small piece of the ½” thickness of HDPE to use for a few other small pieces of the destemmer and crusher that I had in mind.

The Garagiste’s Destemmer

Page 2 of 13 © Steve Hughes, 2011

Next stop was the hardwood lumber yard. The main destemmer shaft would be made from a full 2” x 2” x 36” long piece of maple, selected for its hardness and resistance to absorbing liquids and bacteria. I’ve been told that maple has a resistance to bacterial contamination which is why it is a material of choice by chefs for restaurant cutting boards. They had just the piece I needed -- straight and already cut to length -- and in their “scraps” bin. I also picked up a half sheet each of ¾” and ⅜” plywood and 12 feet of ½” hardwood dowels and some ½” x 2” maple.

Then it was off to the hardware store for 12’ of ½” plastic tubing, several sheaves (pulleys) in a number of sizes. I kept the receipts so I could take back the ones that I didn’t need, but wanted to experiment with various sizes to get the speed of the destemmer shaft and crusher rollers set just right. The shopping cart also got filled with lots of screws, washers, nuts, bolts, some steel rod, and draw bolt clamps.

Finally I headed down to the warehouse where the contractor supply dealers had me go to pick up the pre-ordered plastic laminates (think Formica™ countertops) that I would be covering the crusher and destemmer’s wood surfaces so the equipment would be protected with durable, easy-to-clean, impervious materials. They also had some edging tape that would be used to cover the edges of the boxes and the contact adhesives I needed.

Fabricating the Basket

At one point in my crusher observations while wine tasting at a lovely winery, I was scrutinizing the stainless steel basket of their very nice (and expensive) destemmer and wanted to have a gauge of how big the holes were. So I nonchalantly stuck my finger carefully into the hole on this stainless basket and it got snug at my first knuckle. When I started laying out my new basket, I flashed back to the winery, the basket, the finger, and then got out my tape measure and measured the diameter of my knuckle; about ¾”. I then laid out a grid of ¾” holes in my CADD program to get a good layout with similar spacing to commercial baskets. This would become my template. The grid turned out to be ½” x ¾” with holes being placed in alternating intersections. If you don’t have a CADD program, you could make the same pattern with a piece of graph paper. I printed out the template and brought it out to the workbench to lay out the array of holes.

Keeping in mind that I wanted to have the equipment fit in the small space over my barrel room, I decided that the diameter of the basket couldn’t be more than 12”, so doing a quick calculation of 2 x pi x r, I determined the final width of the HDPE sheet would be 18-⅞” if it were to be a 12” half-circle. Using a nail set, I poked holes in the paper template at the center of each basket hole mark plus some “match-line” holes to align the template as I moved it across and down the sheet. I found that just about nothing marks HDPE except a permanent felt marker. I taped the template in place and then marked the center points of each hole.



The hole locations were marked through a template that had the center points punched.

Once they were all marked I drilled the ¾” holes. I used an old tapering bit I had inherited -- it made nicely tapered holes that could be a bit gentler on the grapes than a sharper hole edge might be. I’m sure a high speed ¾” bit would work just fine, however. Don’t use a hole saw unless you want this task to take forever. About 500 holes and a couple hours of drilling and the basket starts to take shape.

Drilling the HDPE sheet worked well with the tapering bit drilling into a hole below in the 2x4. The purple mark on the bit kept the drilling depth consistent.

The basket has side supports that are fabricated from ¾” x 3” maple. I made a ⅛” x 2” high rabbet on one face of this piece, then ripped the top and bottom at a 45º angle and cut to length 1-9/16” longer than the HDPE sheet. Each end of these side supports was then cut back ¾+” and up to the top of the rabbet so as to overlap the end supports. The edges of the basket then get screwed into the rabbet and the slant at the top and bottom will keep hard-to-clean sharp corners to a minimum. I drilled and counter sunk holes and screwed the long edges of the basket to these side supports.



The final pieces for the basket support are the two ends. They are cut from the ¾” plywood, each piece being 13-⅜” wide by 7”. I marked a 6” radius semicircle centered on the top edge, leaving a ⅝” wide square top and removed the semicircle, forming the end supports of the basket. Then I set these parts aside to focus on the destemmer shaft.

Building the Destemmer Shaft

I double checked the shaft profile is a full and square 2” x 2” by running it through the table saw each way. It’s easiest to prepare the ends of the shaft for the metal axels before reshaping the shaft into the 12-faced piece, so I took a couple of preliminary steps: (1) Cut a 2” long piece of the 2x2 and set aside. (2) Cut the shaft 1-½” shorter than the length of the basket. Mark an “X” across each end of the piece to identify the center point of the shaft for future reference and punch a small hole in this center point with a fine nail set.

Drilling the Ends of the Shaft

Next I needed to drill a hole into each end to insert a ½” steel axel. This is a very difficult procedure, even with very sophisticated woodworking equipment. After trying a lot of different approaches, I managed to come up with this method to help make reliably centered, straight and in-line holes into the shaft. If these holes aren’t, the shaft or pulleys will wobble.

I start by making a corner-to-corner “X” on the center of the end of the 2x2 block and then with my drill press drill a ¼” hole down through it. Then I enlarge the hole to ⅜”, then up to ½”. This gradual process keeps the hole centered and square to the piece. Next, I clamp this block to the tail end of the fence of the table saw and down to the table, with the hole horizontal and in line with the fence. Then the 2x2 shaft is clamped to the saw’s fence and against the block with the hole in it.

I put a ½” bit in my cordless drill motor and insert it into the hole of the block and slowly drill into the workpiece taking care not to reshape the hole in the block. Drill a little, withdraw the bit to remove the cut wood, then drill a little more and repeat until the hole extends the full length of the bit, about 2” into the shaft.

Shaping the Shaft

Once both ends are drilled I set out to turn the four-faced piece into a 12-faced piece, each face being 9/16”. I screwed a wood auxiliary fence to the metal fence of the table saw and tilted the saw blade to 30º, and raised it to 23/32” to the high point of the blade above the table. Turning on the saw, I slowly press the wood fence into the rotating blade until the left side of the high point of the blade is flush with the face of the fence. I make the first rip, removing a 30º triangle from the side of the stock. I repeat this for each of the other three faces of the 2x2.



With eight passes through the table saw, the destemmer shaft is converted from a four-sided piece to a twelve-sided piece.

The next step is to place the piece on these cut faces on the table of the saw and make similar 30º cuts. Four passes through the saw and we have the 12-sided shaft, each face 9/16” across. A bit of sanding and the shaft is ready to drill the holes for the finger dowels.

The final shape of the shaft with the center located on each end.

I marked the length of the shaft to drill the holes every 1-¼”, starting 2-½” from the end that will be the infeed end. A little trick I use to make marking these quick and easy (avoiding math) is to mark the zero location, then the first 1-¼” mark then every 5” increment (5, 10, 15, 20, etc.) Then move the tape to the first 1-¼” mark and repeat until I have all the increments filled in. Each subsequent mark gets made on the next face of the shaft, by starting from the motor end on the left and rotating the shaft towards me. So, looking down the shaft from the motor end, the holes rotate counterclockwise and they get farther away. I place the shaft on the drill press and drill ½” holes through each mark, ultimately drilling 24 holes.

Installing the Finger Dowels



The wood dowels form the roots of the fingers that will push the clusters through the destemmer basket. I wanted the destemmer to be gentle on the grapes, not ripping the skins excessively, so the wood fingers only extend half the length of the final fingers. That said, they get cut at just a hair less than 6” so there is virtually no waste except sawdust.

Pressing them into the holes of the shaft could have been done quite easily with a machine press, but I didn’t have one, so I rigged up a jig using my vice, a pipe clamp and a 2x4 block with a ¾” hole drilled into it. The shaft was held in place with the vice and the pipe clamp pushed the dowel through the hole and into the hole in the 2x4 until each one was pressed through, centered on the shaft. They were a very snug fit, so no fasteners are necessary to hold them in place. When they were all installed they formed a nice looking helical piece.

6” hardwood dowels are pressed through ½” holes in the shaft drilled helically along the length.

Inserting the Axels

The two axels are ½” steel rods, with the one on the motor end having threads and the out-feed end is just a straight rod. I thought for a moment about trying to thread the end of the rod using a hand held die but then realized I could just buy a half inch bolt and cut the head off and get the same result without having to buy the die. So I drove the rods into the ends of the shaft and to keep the shaft from spinning on them, I drilled through the shaft and axel and put a small bolt through them.

Finishing the Fingers

As I mentioned earlier, I wanted the destemmer to be gentle on the berries, so the fingers should be slightly flexible. Some ½” PVC tubing fit the bill for this. I cut the tubing at 4-¾”” so they would come within ¼” of the basket when spinning. Once all 24 pieces were cut, I slipped them over the wood dowels all the way up to the shaft and put a small screw through them into the wood dowel to keep them in place.



The last shaft consideration was to create a washer for both ends. Cutting a couple of 2” diameter axel washers from the ⅛” HDPE with a hole saw worked very well to allow the shaft to spin freely with minimal friction inside the destemmer box.

The shaft is completed with pieces of PVC tubing slipped over the dowels and the axel rods are pressed into the ends. Washers and bearings are also fabricated from HDPE.

The Destemmer Box

I cut the sides and top of the destemmer box from the ⅜” plywood. Before assembling the box, I applied plastic laminate to the inside faces of the pieces, including the basket end supports. Once the laminate was glued on, then the sides were glued and screwed to the basket supports and then the ⅜” piece for the motor end was installed. The top of the out-feed end was supported with a piece of ¾” x 2” laminated plywood.

The pieces that make up the box of the destemmer are laid out in preparation to be covered with plastic laminates.



The assembled destemmer box as seen from the motor infeed end. The coupler nut on the shaft allows for the pulley to be removed easily and then the shaft pulls out for cleaning.

The top of the box was designed to support the out-feed end of the shaft as well as to be quickly removable in the event of a jamb up and for easy clean up. In order to accomplish this, the top was cut an inch wider than the width of the box and then screwed to a piece of ½ x 2 maple on each side. Then to support the out-feed axel, I fashioned a “T” shaped piece from the ¾” plywood and screwed the top down into it.

The top of the destemmer box has the axel bushing installed on the Tee-shaped support. The top then slides over the axel and holds the shaft in place.



Installing the Basket

With the interior of the box finished out, I curled the basket and pressed it down tight onto the semicircular end supports and clamped the side supports to the sides while I screwed through the sides and into the supports. All the screws on the exterior of the box were countersunk flush with the surface of the box.

Once all the pieces of the box were put together and the basket was secured in place, I finished the exterior with plastic laminate and edge banding.

Installing the Shaft

In order to get the shaft centered in the basket and maintaining the ¼” clearance all around the fingers, I marked a line 6” up from the bottom of the basket on the motor end, then centered between both sides. At this location I drilled a 9/16” hole. I then cut a 2” square piece of the ½” HDPE and put a ½” hole in the center of it with the drill press. This piece will provide the bushing for the axel to spin in. HDPE keeps the noise down and requires no lubricants. I screwed this piece to the outside of the box, centered on the 9/16” hole in the box. I then fit the shaft with the washer in place into this hole, and then placed a number of ¼” shims under the finger tubes to center the out-feed end. I rubbed the end of the out-feed axel with a pencil. I follow up by setting the top in place and pressing the bushing on the “T” against the axel to mark the location for the hole in it. Again, I drilled the T with the 9/16” bit and then centered another piece of 2x2 ½” HDPE over the inside of the T and screwed it in place. The top then slides over the axel, holding the shaft in place.

Now that the top is set in place and the shaft spins clear of the basket, I secured the top to the sides of the box with a couple of draw bolt clamps (the kind you used to have on your lunch box) on each side of the box.

The Motor Assembly

I was able to scavenge a motor from an old power tool I had that was worn out except for the motor. I cleaned it up and installed a switch box to the power cord, then mounted it to the side of the box. Unfortunately it was a faster speed than would be ideal for the destemmer, so I needed to “gear” it down by adding a speed reducing pulley. I wanted the shaft to spin at about 150 to 200 RPM’s and the motor was rated at 3,450 RPM. So I installed a 1” sheave on the motor and an intermediate 6” sheave on the reducing mechanism. Then next to the 6” pulley, I added a 2” pulley which will drive another 6” pulley on the destemmer axel. Finally I slipped on the V-belts and test-turned the pulley system by hand. With this system, I was able to reduce the speed of the shaft down to 190 RPM without a load, so while under load with grapes running through, it was right about the speed I needed.



For cleaning purposes, I wanted to be able to remove the destemmer shaft so rather than just installing the pulley to the axel as it protruded through the end of the box, I threaded a coupling nut onto the axel, then threaded another headless bolt with a flat spot ground on the end, into it, onto which I installed the 6” pulley. Now I can unlatch the top, hold the pulley and unscrew the shaft from the coupling nut and the whole assembly is disassembled, ready for cleaning.

Finishing Touches

I held my breath when I first turned the motor on, expecting something would come flying off, or fall apart, or… Just a couple of adjustments were needed to the speed reducing mechanism to tighten the belts. The opening on the out-feed end ended up being large enough to allow the clusters to move through the destemmer too freely, so I added a piece of plexiglass to cover up about half the opening which allowed just enough resistance for the clusters to get picked clean and almost no jacks fell through into the must.

The Stand, The Bin, The Stem Cart

I’m a firm believer in making your work as ergonomically efficient as possible, so to facilitate this I built a stand that the crusher sits on. And to make this stand one that would also serve multiple functions and take up as little space as possible, I designed it to fold up flat to about 3”. In addition I wanted to take advantage of the ability to move heavy stuff around on it, so I added some 3” casters to the legs. So with the legs folded out, this stand wheels out into the crush pad where I place the destemmer on top. Then, I use a 25 gallon Rubbermaid Roughneck bin on a



The destemmer exterior is laminated and the motor and switch attached.

The drive pulley is removed from the destemmer axel, in this case allowing for pre-crush sanitizing of the basket and box. The semi-circle piece from the basket end support becomes a motor speed reducing mechanism and belt tightener.

dolly and roll that under the destemmer. During crush, the berries fall through the destemmer basket into the Roughneck. When it is full, the dolly rolls over to the fermenters and we use our 3 quart “must pump” (sauce pan) to scoop out as much as necessary until the bin can be picked up and the must dumped in. While the “pumping” is going on, the dolly gets fitted with another Roughneck and the crush continues.

The destemmer sits on a folding, rolling stand that sits over a plastic bin that the grapes fall into when destemmed. When full, the bin then gets rolled over to either the press or fermenter for unloading.

Another consideration I made in the design of the stand was the height of the mouth of the garden cart I place at the out-feed end of the destemmer. The cart wheels up to the destemmer and the stems just fall into the cart. When it’s full, the stems get wheeled off to the compost heap to be used to enhance the soil in the backyard vineyard next spring.

<<Photo 12: Crush Completed>>



A garden cart wheels up to the outfeed of the destemmer to collect the stems.

In the next issue, I’ll walk through the construction of the crusher and it’s connection to the destemmer.



A garden cart wheels up to the outfeed of the destemmer to collect the stems.

Documents

The Garagiste’s Destemmer - Homebuilt · PDF fileNext stop was the hardwood lumber yard. The main destemmer shaft would be made from a full 2” x 2” x 36” long piece of maple,