I was just stressing out the concept of how the grind size affects extraction rate

another_jim wrote:Why are all these extraction discussions like someone trying to weigh a box with a tape measure?

As far as I can tell, this will be the first time this symbol has been witnessed in this thread: %

This route is about getting a better cup without numbers... which I think is congruent with your position on the matter.

The idea being given two beverages with equal brew ratio and equal strength( objective or subjective, take your pick), the coarser ground option probably tastes sweeter by way of less over-extraction of fines.

The implication in espresso might be that one could lower brew pressure to increase brew time and get a bigger sweeter cup... perhaps as seen in lever shots. This path might even be extended to reducing brew pressure down to 2bar (line pressure) and increasing brew ratio to say 1:15, and having a relatively clean cup due to so few fines and such low turbulence that very little sediment gets past the filter.

I appreciate that. I especially appreciate going against current trend of finer ground is better.

My thought is more general: extraction, as a concept, is such a useful way of clarifyng the discussions about dose, grind and brew cycles that it blinds people to everything else that is going on. I'm especially concerned about how the narrow focus on extraction and the trend towards lighter and faster roasts seems to be heading down the rabbit hole.

I was certainly on that trend of grinding finer and finer; past when my own roasting had shifted away from the need. Had I received the advice to grind coarser earlier, it may not have proven so fast. Part and parcel of the discussion is without a doubt the roasting itself. Today, I'm of the opinion that great solubility and fast + light roasting are not mutually exclusive.

That said, I think finding a grind size that minimizes fines first, then adjusting brew time to suit flavor second carries merit for well and not so well executed roasts alike. For espresso, I think pump pressure should be as or more comfortable a variable than any other. It more directly and singularly affects brew time than grind size or dose.

endlesscycles wrote:I think finding a grind size that minimizes fines first, then adjusting brew time to suit flavor second carries merit for well and not so well executed roasts alike.

Let''s not forget agitation, temperature, filtration and the quirks of specific brewers. For instance, immersion time in a balance bean siphon is more or less set by the general design and limited by the size of the brewer and the diameter of the siphon. Grind size has to be appropriate for the hardware.

For espresso, I think pump pressure should be as or more comfortable a variable than any other. It more directly and singularly affects brew time than grind size or dose.

With vibe pumps, circuit pressure -- up to the limit set by the OPV or pump's maximum -- depends on resistance created by the puck; yet another function of grind/dose. Is that a positive? I'm not sure that with straight pump machines, treating pump pressure as a variable is a good idea. It's nice to have at least one thing fixed.

Levers and pressure profllers -- different story.

Rich

I recently stumbled across this old post from David Walsh which also advocates grinding coarser. It's a good read for those who haven't read it before. Sometimes it's funny to see how similar topics get refreshed over time.

Thanks for that link. Interesting post with a very amusing analogy.

The physics of bean grinding, however, says that the finer the grind, the more fines (dust-like tiny particles) will be created, regardless of grinder. Whether you have a Mahlkonig Guatemala or a Rancilio Rocky this holds true. Conversely coarser grinds produce fewer fines.

Over the course of a brew these fines will overextract in relation to the normal sized grinds, typically creating a bitter, muddy taste. I've heard it mentioned that the fines add complexity, I would argue brew a cup of 100% fines and see how complex you find it. A turd in a swimming pool probably makes the swimming pool more complex.