Posted Thu Feb 2, 2012, 11:19pm Subject: Improving the Porlex grinder's coarse grounds
I recently bought the Porlex mini grinder as a travel grinder because I heard such good things about the spring inside reducing variability in the grounds size. Well, the fine grind turns out great, but I was pretty disappointed with coarse grind for French press because there really is a ton of dust mixed in. Checking out what’s going on with the burrs, I found two problems that can be solved with very inexpensive materials.
Problem 1: The conical burr mounts onto a plastic shaft, but it’s not a tight fit, so the burr can wiggle up and down, left and right on the shaft a small amount:
Posted Thu Feb 2, 2012, 11:19pm Subject: Re: Improving the Porlex grinder's coarse grounds
Solution: put a little poster putty onto the notches of the plastic shaft and then reattach the conical burr. Use plenty of putty to really give it a tight fit, and the wiggle will be eliminated:
edit: as is reflected in the discussion below, the poster putty didn't turn out to be a good enough "glue". So, I used a quick-set epoxy to glue the ceramic conical burr to the plastic mounting piece.
Posted Thu Feb 2, 2012, 11:20pm Subject: Re: Improving the Porlex grinder's coarse grounds
Problem 2: The way the burr set works is the conical burr moves up or down when you adjust a screw. A spring attempts to keep pressure on the conical burr from the other side. That would work ok, but the flat burr isn’t fixed! The only thing keeping the flat burr in place is the housing behind it, and the conical burr itself. At a fine setting, the conical burr nicely pins the flat burr against the wall behind it, so the grind is more consistent. But, at a coarse grind, the flat burr is free to move up and down as it pleases, or as beans push it this way and that. You can even move the flat burr up and down with two fingers. This is one grind setting and I am just pushing the flat burr up:
Posted Thu Feb 2, 2012, 11:21pm Subject: Re: Improving the Porlex grinder's coarse grounds
Solution: Sure, you could glue the flat burr to the wall behind it, but this is not so good for when you want to replace the burrs. So, shim the flat burr in place with 4 uniformly thick rolls of paper shoved in the gap around it. The only moving piece will then be the conical burr, which sets the grounds size:
Posted Thu Feb 2, 2012, 11:22pm Subject: Re: Improving the Porlex grinder's coarse grounds
This seems to greatly reduce the number of fines at a coarse setting. Here are the grounds with no paper shims in place. Ew, look at all those nasty fines waiting to sludge up your cup:
Posted Thu Feb 2, 2012, 11:23pm Subject: Re: Improving the Porlex grinder's coarse grounds
Here are the grounds at the same setting but with the shims in place. It's not perfect (neither is the quality of my photography), but it is better. I can feel with my fingers the larger amount of dust without the shims.
Posted Thu Feb 2, 2012, 11:23pm Subject: Re: Improving the Porlex grinder's coarse grounds
Do I have completely even grounds now? Nope, because I don’t think the conical burr was manufactured to be completely level in relation to the flat burr. The space between them is a little wider on one side and a little narrower on the other. Also, the spring keeping the conical burr in place still allows it to move up and down with a little force, and the adjustment screw surely doesn't stay perfectly in place either. Oh well. I think this reduces the number of fines even if the sizes of the larger rocks isn’t perfect.
Posted Fri Feb 3, 2012, 5:39am Subject: Re: Improving the Porlex grinder with paper and poster putty
Thanks for posting the details of your mod, which reminds me of what people have felt compelled to do with the Hario Mini Slim in some respects. Think I'll hold out for OE's Lido (ETA: March).
calblacksmith Moderator Joined: 25 Nov 2007 Posts: 5,761 Location: Riverside, Ca, U.S.A. Expertise: I live coffee
Espresso: ECM Veneziano A1 Grinder: Many different commercial Vac Pot: 40s era Silex Drip: Milita, Bunn&Curtis... Roaster: Cast iron pan, gas burner
Posted Fri Feb 3, 2012, 9:33am Subject: Re: Improving the Porlex grinder with paper and poster putty
The only thing I can see that may be an issue is that you are using a putty to take up slop. If the putty does not dry, it will eventually squish out and you will be back to square one. Other than that, good job on moving the grinder up a notch or two on the scale :D
In real life, my name is Wayne P.
Feed the newbs, starve the trolls and above all enjoy what you drink!
Dang it. I had no idea about the LIDO. Hope it costs so much I won't mind having spent money on the Porlex. =-) Yeah, it's sort of fun modifying this equipment, but I wish I could just buy something that did it's job better in the first place. Depending on the cost, I might buy the LIDO too. The Porlex was sort of an impulse buy. I'm pretty unimpressed with the mounting of the burrs. The most unfortunate design is that the stepped adjustment has plastic notches that rub together. Over time, this will probably wear the steps completely out. At $65 - $70 for the Porlex, had I known all this, I probably would have gone with a different grinder.
calblacksmith Said:
The only thing I can see that may be an issue is that you are using a putty to take up slop. If the putty does not dry, it will eventually squish out and you will be back to square one. Other than that, good job on moving the grinder up a notch or two on the scale :D
Thanks, Wayne. The paper shims work really well from what I can tell so far, however you are right about the putty. The conical burr is already starting to wiggle in its plastic shaft. Moreover, the putty is partly responsible for the uneven gap between the conical and flat burr. If the putty isn't perfectly allocated between the sides, it will turn out unbalanced when you slide it onto the grind shaft. I'd even be afraid to glue the burr onto the plastic because I'm not sure how to judge when it's level until I actually grind and see/hear the burrs.
So, I am getting my best results with paper shims only and leaving the conical burr alone (no putty). It is what it is. Had the conical burr been threaded onto the grind shaft by the manufacturer, this would have been a much better grinder.
For now, I am looking into getting a spring with greater tension, thus eliminating some up/down wiggle from the conical burr.
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