No idea if lowering the RPM would make a difference, which is why it is called testing. Observation and mental concept says it should in my mind. If you hit a baseball with a bat swung at half the speed, the ball will not go as far. Hit a bean with a burr at lower rpm, it should bounce less.

cannonfodder wrote:I bet turning down the burr speed would reduce popcorning with low doses.

Something that I would be interested in for sure. I bought mine new ~5 years ago and paired it with a plumbed-in Curtis. My only gripes are popcorning with less than 1/2 lb of beans in the hopper and the difficulty, or maybe I should just say the PITA, with adjusting the grind.

This is defiantly not a grind adjustment friendly grinder. The adjustment is under the machines grind dispenser and takes a screwdriver to adjust.

The grinder has been rebuilt now, see BUNN LPG bulk grinder rebuild for information on that.

I brewed my first cup today with the new grinder. I eyeballed the grind, I believe I need to tighten it up just a bit more. I am using my BUNN plumbed in brewer that I have set for a half pot at 201 brew temp. Todays coffee is a nice Costa Rican San Bosco Tres Volcanes I roasted 3 days ago.

The ground coffee appears to still have some fines in it, or rather finer than most granules. However it does not appear to produce much in the way of dust, or fines of the same size that my espresso grinder produces. That is reflected in the cup. I am not getting that over extracted bitter note I get with the espresso grinders. My experience with other bulk grinder is limited so I do not have much of a base for comparison but it tastes like a nice cup. I drink my coffee black so there is nothing to disguise off flavors. I am getting a light floral note in the cup along with a pleasant sweetness and light orange with mild acidity and no bitters at all. Not bad for the first cup ever brewed from the grinder. I need to tighten the grind to see what effect it has. The cup is a little weak, a tighter grind may pull out more body.

A while back I bought a grindmaster for work (ebay). At the same time I bought it, I also bought a new set of burrs. But at the time of changing the burrs, the new set of burrs did not work as good as the old ones. I think it had to do with a brass bearing or the burrs being brand new.

The grindmaster burrs may be better old.

This is an interesting article as I was going to upgrade my rocky to the Mazzer SJ as use the rocky as a coldbrew/brew coffee grinder.. Seems i might have to look into bulk grinder down the track to make the ultimate aeropress.

Other than Ditting and Mahlkonig what foreign grinder manufacturers have brewed coffee specific grinders for small cafes abroad? Or do they just use doserless espresso grinders? Does a company like Mazzer make burr sets specifically cut for a coarser brew type grind?

Compak comes to mind as a foreign bulk grinder manufacturer. I've seen theirs in use at a local shop; it seems pretty nice, certainly more attractive than a Guatemala, but I have no idea about the 'unimodality' of its output or the relative quality of the cup it produces.

another_jim wrote:Espresso grinders end in either a solid outer/lower ring or one with extremely narrow grooves cut in. Bulk grinders have the same burr configuration but no outer ring. This is true of all the bulk grinders as far as I can tell.

For your reference: Some close-up pictures of the lower burr of Mahlkönig Tanzania (the upper burr is similar).

jiitee wrote:For your reference: Some close-up pictures of the lower burr of Mahlkönig Tanzania (the upper burr is similar)

Great to see these pics! Very illuminating.