Alan Frew wrote:Now, if you want to raise the bar from "mediocre" to "good", try checking out the original aim of the experiment (that lower inflow temperatures and lower coffee volumes can give the same level of extraction and flavour IN THE CUP as higher inflow temperatures with higher coffee volumes) with Bob & Jim sucking shots. Forget the "Lungo, Normale, Ristretto" bull, give me milliliter shot volumes! Tasting notes! Grinds in, coffee solids out extraction ratios!

I suspect that you probably already have the data, but haven't thought through the presentation and conclusions yet. What we really need to know is if a 7g/88C/25 sec/30ml single tastes the same as a 14g/93C/25 sec/30ml single, due to cooling and flow factors in the puck.

hi alan
i'll step in for andy for a sec, given that he already does too much of the work around here:

hopefully you've seen his posts about brewing ratios and measuring shots by mass instead of volume; if not, please check out:

brewing-ratios-for-espresso-beverages-t2402.html

that thread will explain why discussing shot volumes is misleading and not useful for such an experiment.

also, the original intent of the experiment was never to prove that lower dispensing temp/smaller doses would produce exactly the same flavor as higher dispensing temp/larger doses (they won't, for more reasons than just the issue at hand). the intent of my thought experiment was simply to point out that the difference in mass between the typical italian dose (7g) for a "single" (the dreaded volumetric 30ml) and the typical "third wave" american 20g dose for a 30ml shot may be a factor in why italians recommend lower temps and americans prefer higher temps. nothing more and nothing less was intended.

andy, as usual, fine tuned the idea by substituting the more precise idea of brewing ratios and shot mass.
scott

another_jim wrote:The top of the puck extracts early in the shot, the bottom of the puck, late in the shot. So by the time each section of the puck is extracting, the water temperature has risen to close to the inflow temperature.

That is a great point. The top-to-bottom extraction undoubtedly blunts much of the effect of the average extraction temperature difference when going from ristretto to lungo.

another_jim wrote:the self correction may be going too far. Ristrettos tend to be more bitter and over extracted than normales

Interesting. I generally don't perceive them that way. Heavy, oily, intense -- Illy theorizes (2nd edition p.304) that the oils tend to block our perception of bitterness, so perhaps the bitterness is there but I'm just not tasting it as much.

cafeIKE wrote:In the restricted shot, the coffee spends about twice as much time at temperature as the quick shot.

That graph is puzzling to me. It says that it takes about 16 seconds for the bottom basket temperature to reach max in the the fast shot. And maybe 18 seconds for the same thing to happen in the slow shot. Seems like there oughta be more a lag in the slow shot, no? Am I reading the graph wrong?

Alan Frew wrote: What we really need to know is if a 7g/88C/25 sec/30ml single tastes the same as a 14g/93C/25 sec/30ml single, due to cooling and flow factors in the puck

Oh gosh, if those tasted the same, I'd switch to tea (sorry, Scott ). Or maybe Coca-Cola.

AndyS wrote:That graph is puzzling to me. It says that it takes about 16 seconds for the bottom basket temperature to reach max in the the fast shot. And maybe 18 seconds for the same thing to happen in the slow shot. Seems like there oughta be more a lag in the slow shot, no? Am I reading the graph wrong?

You're reading it correctly. Admittedly, I was not investigating ramp time*, so the log is not triggered** by pump activation. Just YHS lifting the lever and hitting the log button, probably ±0.75 sec depending first or third shot of the day. I didn't expect the ramps to be so close either when I first graphed the data. If I get some time, I'll rerun a more controlled test.

[* I was looking at shot profile w / wo heater on during the shot over long and short shots ]

[** I'm not certain of the logging function start on the Extech : If I hit LOG at 1.1 seconds, is the first sample recorded at 2.0. Next time I could log continuously and start the pump on even seconds. More note keeping ]