Arpi wrote:It does. It has a big impact on flavor.
I've tried different variations of this technique; I have a hunch about the flavor impact you're noticing and why. First the flavor impact, then why.
The enhanced sift extractions I've tried are more front loaded, i.e., they start out darker than unmanipulated grounds and blond slightly earlier. The flavor profile shifts in favor of the first third of the extraction, enhancing chocolates and base notes, similar to the taste profile of a ristretto with greater volume. Does this sound familiar?
I have no easy way of proving it, but I suspect the "why" is because the sifting/agitation encourages fines separation, resulting in more fines at the bottom of the basket than the top. This enhances the impact of fines migration that is normally under the exclusive influence of incoming water. Of course, this is pure and absolute speculation on my part and I'm unwilling to dry, slice, and weigh enough pucks to prove it.
