beancrusher wrote:Curious about RPM settings. Are people finding that low RPM = faster flow and faster RPM = slower flow? How many grind setting adjustments would you say are equivalent to going from 30RPM to 150RPM? I've had the grinder for a week or so and want to see what other people's experiences are with dialing in with RPM as a variable with respect to flow and taste.

No it is actually the opposite faster RPM = faster flow, and there is a different in taste too

On any grinder with variable RPM a faster grind setting will produce more fines than a slower grind setting. This will therefore produce a slower flowing shot all things equal.

This last part is what confuses people. Puck prep is a VERY DIFFICULT step to get down to the point where it isn't THE major variable from shot to shot.

The other thing to note is that regardless of what a manufacturer says, until you get 20+ pound of beans through a set of burrs you're just not going to see shot to shot consistancy on the level needed to start assessing what RPM tastes best.

FWIW my Monolith Flat is variable and I run it at 650RPM. My Monolith Conical 4 is fixed at 120RPM.

Might be the case with most grinders, but certainly not with several hand grinders I've dialed in. Maintaining the same angle and actually timing/counting the cranking, a slower speed does indeed give more fines and slower extractions all things being as equal as possible.

All reports I've seen for the Key are that faster RPM gives faster flow, but the RPM of the Key is much lower than most electric grinders so the results may mirror hand grinders as mentioned above.

PIXIllate wrote:On any grinder with variable RPM a faster grind setting will produce more fines than a slower grind setting. This will therefore produce a slower flowing shot all things equal.

Maybe not for EG-1.
Grind speed RPM changes--what effect are you noticing?

I maintain, after PROPER seasoning (20+ lb) and with shots prepared identically, slower RPM will produce fewer fines and faster flow. That graph did not indicate either of those requirements had been met and was provided by the distributor.

Until you can change no variables and pull back to back to back shots that run within 0.1g and 1 second of each other you're not in the position to isolate and test a variable like RPM. Both improperly seasoned burrs and less than perfect puck prep can prevent this.

I am now in a position where both my grinders have been seasoned and my back to back shots run within those tolerances. Before seasoning my new MC4 it became immediately obvious to me that neither was the taste even close to optimal nor was it possible to achieve back to back consistancy. My puck prep leveled up when I got my Monolith Flat over a year ago and I was forced to isolate more variables and work on them. The Conical is more forgiving but not by much when I'm trying to meet those tight shot tolerances.

I can just imagine how entertained the producers of coffee grinders going onto H-B seeing all the discussions people are having about their grinders when they know all this already through their testing, but sitting back with some popcorn watching it unfold

PIXIllate wrote: I maintain, after PROPER seasoning (20+ lb) and with shots prepared identically, slower RPM will produce fewer fines and faster flow. That graph did not indicate either of those requirements had been met and was provided by the distributor.

There is not evidence that the seasoned burrs produce less fines with lower rpm regardless the burrs type or geometry.
The graph is generated by the laser particle size analyzer, which can avoid the puck preparation issue, but yes, we don't know the burrs seasoning.

PIXIllate wrote: I maintain, after PROPER seasoning (20+ lb) and with shots prepared identically, slower RPM will produce fewer fines and faster flow. That graph did not indicate either of those requirements had been met and was provided by the distributor.

Until you can change no variables and pull back to back to back shots that run within 0.1g and 1 second of each other you're not in the position to isolate and test a variable like RPM. Both improperly seasoned burrs and less than perfect puck prep can prevent this.

I am now in a position where both my grinders have been seasoned and my back to back shots run within those tolerances. Before seasoning my new MC4 it became immediately obvious to me that neither was the taste even close to optimal nor was it possible to achieve back to back consistancy. My puck prep leveled up when I got my Monolith Flat over a year ago and I was forced to isolate more variables and work on them. The Conical is more forgiving but not by much when I'm trying to meet those tight shot tolerances.

My Grinder is over 10KG seasoning and my puck prep is on point since I brew with lagom p100, I have brewed back to back shots with same bean and clearly lower RPM brew much much slower. Many people in the forum have experienced the same trend, and James Hoffman mentioned it in his last video about the key. I am not sure why it is different with you.