cannonfodder wrote:Most bulk grinders use a comparatively rough set of burrs with one or two cutting zones and relatively large teeth. I would think that these large teeth would chunk the beans into rough, ill formed and varying sizes. I may be simply chasing a white rabbit and there is no real answer other than, they just do. I thought I would pose the question anyway since I am looking for a dedicated drip/press/vac grinder.
This sounds like some great work is in the offing. Cool.
I've been wondering about how these different grinders work too.
Our friends at Marco have been publishing some data about this for while.
Based on some sketchily described taste tests, they have concluded that a screened grind or the produce of a highly unimodal grinder set around a .8mm median particle size make the "best" press cup. Inclusion of a higher percentage of fines degraded the brew. This seems like a straight-forward conclusion.
There's always been a paucity of info about what different grinders do at drip or press settings. The Marco folks promised a few months ago some comparative data between a cast steel burr grinder (like the kind in Jim's grinder above), a "dragon's tooth" type of burr like the kind in my old commercial Hobart, and a burr set they are developing that looks much like the general design found in the Mazzers and MACAPS and similar grinders of the world. I prodded Paul to post the results recently, and he just did:http://marco.ie/uberproject/?p=401
The "espresso grinder" design (for lack of a better label) produced the least fines, the "dragons tooth", the next least, and the cast burr the most. Whooo ha.
Kyle at Baratza recently contributed a graph made on the same measuring equipment for the relatively cheap Virtuoso grinder. See it here:*Which* Baratza grinder for drip/press?
So, there's a cheapish grinder that can produce a unimodal particle curve at a press setting competitive with the best.
What's all this mean in terms of comparative cup quality? Inquiring minds want to know...