The role of fines and what we really want from a grinder - Page 3

Grinders are one of the keys to exceptional espresso. Discuss them here.
User avatar
cafeIKE
Supporter ❤

#21: Post by cafeIKE »

Jasonian wrote:I feel the need to inject the notion that the coffee particles aren't randomly shaped. They are ribbon slices.
The SEM images here don't appear to support that notion.

User avatar
RapidCoffee
Team HB

#22: Post by RapidCoffee »

darrensandford wrote:This makes me want to brew a shot, then dry the puck, then slice it into layers, crumble it and then see how many fines are in each layer :)
You may laugh, but this is actually an excellent proposal for studying fines migration. Jim Schulman has wanted to do this for some time.
John

User avatar
RapidCoffee
Team HB

#23: Post by RapidCoffee »

fac10 wrote:I recently ran across this article which may be of interest to those following this thread. The most interesting point being that some high-end industrial grinders are capable of generating 'bimodal' grinds, where the particle size distribution has two separate medians. Apparently this has some beneficial effects, at least with respect to the manufacture of espresso pods. Presumably, a cruder version of this effect could be achieved by mixing the output of grinders at two separate settings.

Perhaps the blended bimodal grind will be the next bleeding edge in the search for the perfect extraction.
Like industrial roller-type grinders, burr grinders also produce a bimodal distribution of particle sizes. There is ample evidence for this, including particle size distribution studies during the Titan Grinder Project. Grinders work by crushing the roasted coffee beans between two burrs. In addition to the basic particle size produced by the grinder setting, small particles (fines) are generated as the coffee beans fragment.
John

User avatar
HB
Admin

#24: Post by HB »

Jasonian wrote:I feel the need to inject the notion that the coffee particles aren't randomly shaped. They are ribbon slices.
I believe David Schomer wrote that in one of his books/columns, but these grounds from a Robur don't look like ribbon slices to me:


From Scanning Electron Microscope (SEM) analysis of ground coffee


Coffee grounds from Mazzer Super Jolly
Dan Kehn

User avatar
Jasonian

#25: Post by Jasonian »

Interesting.

Grind particles sure look like "ribbon slices" to my naked eye.

More research is in order, it appears.
Owner - AJ Coffee Company
HB Rocks!