old442 wrote:I haven't looked at the TGP as a comprehensive scientific study but rather an in-depth review. I don't believe that a major scientific study is of value for existing products like these, especially when the question of who would pay for them is asked. If we are talking R&D purposes for a grinder manufacturer then the answer may be different.

The opportunity is too good not to do some testing.

People tend to regurgitate the bs they learned in the psychology department's "method of science 101" classes; mainly to assure themselves that it's way too complicated for them to do anything. Alternatively, people who do tests feel pressured to add all sorts of controls and other stuff. The main thing to know about all knowledge is that you can test until you're blue in the face, and not learn anything. For instance, if you start your car 10,000 times and record how long it takes to fire, you'll have nice bell shaped curve, but you still won't know a damn thing about the ignition system. This is exactly what psychologists do, since it's going to be a while before they can peek under the hood and come up with any hypotheses actually worth testing.

The situation is rather different with the TGP. We have lots of grinders. We have the opportunity to do some high quality physical measurements of ground coffee, we can measure how the grinders' pucks extract, and we can do taste comparisons. We already have several good hypotheses that we'll be testing. These predict how the shape of the particles, the ratio of fines to coarse, and the dispersion of coarse particles affects the mechanics of extraction and thereby the shot's taste.

If the hypotheses check out, we'll be able to do to things. Assess and predict the taste quality, that is the clarity, distinctness, etc of a grinder's shot by looking at the physical data. Compensate for variations in taste profile, that is the brightness, body, sweetness of the shots, by changing dose and grind.

In short, save discussions of "proof" and "certainty" for church or the philosophy forum. If you want to talk about testing espresso equipment, lets hear about solids yields, fines/coarse ratios, coarse grinding times, etc.