Ken Fox wrote:I would absolutely love to see a real study using scanning electron microscopy to evaluate the grind size distributions when coffee is ground with a bean column above and without. People compensate for the absence of a bean column, most of the time, by fining up the grind. But what does that do to the bean fragment distribution? My opinion is, probably nothing good.

I tend to agree, but haven't tested it much. What is interesting is that Versalab specifically recommends that their grinder be used without any beans on top.

AndyS wrote:What is interesting is that Versalab specifically recommends that their grinder be used without any beans on top.

Chicken or egg?

Ike, help me out here. Maybe I get your point, maybe not.

I'm not disparaging the Versalab as I've never laid eyes on one

IIRC, the Versalab uses a DRM burrset. Other high capacity grinders that use a similar burrset use a hopper.
The Versalab is designed for the enthusiast, many of whom load the grinder by the shot.

Is Versalab's recommendation because it makes the best grind or because it's what the owner wants?

FWIW, I've closed the circle and leave beans in the hopper. IMO, it makes for a more consistent, full bodied shot.

I keep around 3 days worth in the hopper. As others have mentioned, I find it not only convenient but necessary with conical grinders. The grind most definitely shifts as you reach the end of the beans. Once dialed in, I need next to no adjustments but as I get to the last two shots worth of beans in the bottom of the hopper, I continually tighten the grind by a couple of notches or more to maintain the grind consistency, or more specifically the shot consistency. My flat burr grinder does not appear to suffer as much from the end of bean run out.

A 3 day supply for me is a half pound. If I am running a pound of the same blend then I refill the hopper every day to maintain the same level in the hopper. I also store my beans in an air tight container.

cannonfodder wrote:My flat burr grinder does not appear to suffer as much from the end of bean run out.

On the M4, it's either two turns finer or two grams of coffee to keep the same shot time.
Neither gives the same taste.

This is a VERY interesting topic for me....I'm intrigued on multiple levels.

Ken Fox wrote:The reason why people do this is that they convince themselves that they must have 3 or 4 (or more) types of roasted coffee available all the time, and they must consume them all the same day, ground from the same grinder.

Hmm....Are there people who have told you this was the reasoning?

Ken Fox wrote:If you buy into that idea, in my opinion, the only way to really do that well is to be willing to use ~50g of coffee beans for each shot. The first 10g is used to clean out the previous coffee, and the last 20g or so to weigh down the bean column.

Does this mean that 20g in the hopper or grinder throat is enough to weigh down the bean column satisfactorily? Wouldn't such a small quantity cause variation from the percentage loss as the shot gets ground? It would seem to me that if one was to try to reduce variation using bean column above the burrs then the more mass available the smaller the variations would be as the column is consumed.

Ken Fox wrote:I would absolutely love to see a real study using scanning electron microscopy to evaluate the grind size distributions when coffee is ground with a bean column above and without.

I would also like to see some objective evidence of any kind.


Y'all please feel free to set me straight. Lord knows I could use someone to help me understand

JonR10 wrote:This is a VERY interesting topic for me....I'm intrigued on multiple levels.


I would also like to see some objective evidence of any kind.


Y'all please feel free to set me straight. Lord knows I could use someone to help me understand

Many have posted here and elsewhere that they use a single grinder to make shots from several different types of coffee per day.

20g for weighting down beans is an estimate based upon what I have seen with my own grinders; your's may be different. This is approximately the amount that I have found is necessary to weigh down the beans being ground by the burrs in order to avoid any needed change in grind setting for the situation where the hopper is used in a "normal" fashion.

ken

I completely agree that loading the hopper in my grinder (a Cimbali Jr.) is crucial (at least for me) in getting a consistent grind.

I used to keep it empty, and only load it on a per shot basis... until the thought occurred to me that pressure above the beans being ground might make a difference. On a whim I dumped 12 ounces of beans into the hopper, and two things immediately struck me: 1) I suddenly needed to coarsen the grind setting and 2) I had a step-function improvement in the consistency and quality of my extractions. Honestly, night and day.

As for the amount of beans you need to maintain sufficient pressure, I'm not sure. I probably have between 40g and 80 g at any given time above the beans being ground. In the Cimbali Jr., there's a small plastic circular chute above the throat of the grinder, that's open around the sides as well as the top. I just top that up each morning. Anything beyond that just starts to fill the rest of the hopper (e.g., around the chute), and I don't think that really applies more pressure than the beans sitting in the throat and the chute. And I don't notice a difference when I'm at 40g vs. 80g of additional coffee in the chute. How's that for scientific rigor?

JonR10 wrote:This is a VERY interesting topic for me....

Yes for me too.
The grind setting should be adjusted with running empty grinder. Now, weather conditions change from morning to evening even though it's winter and sometimes I have open window or a humiditor on etc. Then the conclusion is: the units are all inadequate for home use (anyway this is what is in the manuals written with big bold red letters).
I will buy Versalab one day (but I want Hottop first) - it is designed in such way that it is irrelevant if there are any beans in its (optional) hopper.