JakeLiefer wrote: As new and improved grinders have come on the scene, the preferred method seems to be the 'no distribution distribution' method, with a mound in the center and a tamp to distribute the grinds in the basket. Fans say it results in faster, cleaner, and consistent dosing, with an added benefit of reduced channelling. I'm not discounting this, but I'm just confused how this happens. Could someone with a better understanding of fluid dynamics and physics explain this?
Philip Search wrote:While my understanding of fluid dynamics is limited, there are a few things Ive been thinking about:
1. how much head-space you leave in the basket. The technique of no distribution works best with machines that produce a water flow to the center of the basket (la marzocco and synesso are good examples of this) and when using a basket that gives you some head-space for water to build up before it begins to soak into the coffee. Another thing to consider in this is how the water flows through the coffee bed once full pressure is reached (this happens several seconds into the shot, as the head space has to fill first, then pressure builds).
2. is it possible to re distribute coffee and gain an even density?
3. is an even density going to give you the best taste?
I have spent a long time thinking and experimenting with this, and here is what i know, a slightly denser center produces a more even extraction of the whole puck (based on testing what was left in a puck after extraction; when used with the before mentioned basket. Shots done this way seem to taste better (subjective). Lastly it is impossible for multiple baristi on a bar to conform to a re distribution technique that leaves a error margin of less than .5 grams +/- and even distribution. This is not the case with the other technique.
What tastes best to you?
Philip Search wrote:A good starting place would be to do this experiment with your grinder you have by setting the grind with your normal method and weighing out where you dose is at. Now, at that grind, weigh your dose out, put it back in the chamber and do your normal distribution (tricky i know with out spilling grinds). Next do the same thing but don't re-distribute simply put it all into the center of the basket and tamp lightly to settle, then pull off, then go down with pressure as you normally would (don't tap if you do that). This will create a denser center due to the grinds falling in the middle of the basket. Watch and taste both extractions. They should be a bit different. NOW do the reverse, set the grind and dose by doing the dose to the center technique and then reverse the experiment. Lastly, as a comparison, at both grind settings, don't redistribute, but simply move the portafilter in such a way as to dose in a circle with coffee falling evenly around the basket (easiest with a naked).
nick wrote:Right back at you though: why do you say that "part of the importance of distribution is to ensure that grinds are all the way up to the wall of the basket?" I don't understand what you mean.
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