just did a blind comparison in case anyone is interested. not super scientific at all, and i'd like to try this a few more times just to confirm, but here's how it turned out.

coffee was the guatemala bola del oro from lofted. i've had it vacuum sealed in my freezer for around 3 weeks now. this morning, i pulled 10 grams and vac sealed it, leaving it on the counter to come up to room temp.

i used two aeropresses side by side, both with 10g of coffee (ground in a virtuoso) and 155g water, inverted and pressed after 6 mins. i use a modified version of matt perger's recipe for my water. extraction yield for this recipe sits at around 21.5%, although my refractometer is not here to measure the two cups side by side, unfortunately.

i took a couple of sips from both immediately after brewing. the difference was negligible, although one of the cups was slightly sweeter and had a more pleasant aftertaste. after letting the coffees cool for 10 mins, i came back and had another taste. at this point, the standout from earlier had gained an even further advantage on the other cup. sweetness and clarity were markedly improved, and the finish had a more pronounced chocolatey flavor to it. checking the marking i had made on the bottom of the cup confirmed that it was the one ground while frozen.

I am struggling to interpret Figure 4 to determine if the amount of super-fines was correlated with the temperature of the beans. I can see the fines peak on the surface area plot, but I cannot explain the second peak at roughly 400um, there are so few particles of this size how do they contribute 25% of the surface area? Is it because they are so much bigger than the 10-20um particles? I thought the massive number of fines would still dwarf the surface area of the larger particles. I assume when plotting this graph they had bands of particle sizes to represent the frequency eg <5um, 5-10 um, 10-20um, etc? Ie a bar graph that was converted to a trend.

Basically they did not include enough of their raw data, which is concerning. We need the actual grind profiles with number of each particle size. A change in mode from 15 to 11um between room temp to frozen does not seem significant to the end result in the cup, and the mean particle size did not change at all. As for skewness and relating this to particle distribution, how can one tell if skewness 0.8 to 0.95 (approx) is significant? The

Several less scientific studies of inferior methodology, have shown reduced fines with warmer beans (above room temperature eg by sous vide or as a result of hotter grinders at the end of the day), so I wonder what is happening with the colder beans?

I don't have time to read all the comments here, but I will say that sometimes the media run away with things.

I want to share some data with you, though. Sci Rep didn't have a vehicle for allowing me to present the raw data in a meaningful way, so I have just got it here. As with all science, it is available for 5 years after publishing (in principle the authors should be forthcoming with the data, but sometimes there are good reasons to not. i.e. clash of interests, business motivations, etc.)

Here is a representative data set:
https://www.dropbox.com/s/nfwsnedgfej8h ... .xlsx?dl=0

I think you can play around with it and see what you can make of the profile.
Regarding condensation; you are correct. If the air is moist, the coffee with absorb it. deposition of crystallites on the surface is not the concern! Once ground the coffee will equilibrate to water temperature (or very near it) extremely rapidly. I didn't brew coffee in the paper, but if I had, you wouldn't see a tremendous difference in temperature flux. That high surface area really helps.


Annnnnnyyyywayyyyyy, I gotta roll, but if you ever do have questions about my work, or anything for that matter, send them in an email to me! I will try and be timely and get to it!

Thanks, Charlene.

One caveat. My comment was "...possibly changing our customary habits...," as contrasted with "...we may all need to change our customary habits...." The first implies consideration of evidence as well as experimentation. The second is more absolute and implies some sort of coffee authority dictating methodologies.

New developments in coffee are interesting and are met, like new developments elsewhere, immediately with opposition based on "...that's not how it's done," which argument lacks merit, IMHO. The espresso machine itself was a new development as was the siphon brewer, E61 head, double boiler machines, and on and on. Of course mindlessly adopting new stuff because it's new is as ill-advised as resisting it for the same reason, and your point that empirical method basically rules is quite valid, I think.

There's a lot going on in coffee research at the moment. So much is going on that my head spins sometimes. The variations in roasting theory leave one only to one's own experiments and palate, in the end, to guide one, though it should be noted that one needs to pick a starting point and picking a starting point from someone who's been roasting for many more years, and in a professional situation where they accumulate more experience in one month than I do in a year, seems a reasonable way to hedge bets on what is, by all accounts, a steep learning curve.

There are so many variables in coffee! Sourcing, storage, roasting, brewing all have their own set of difficult-to-objectively-control parameters. Add to that circumstance the panoply of viable hypotheses, and, well, one finds oneself swimming in coffee with nary a life preserver in sight. Best one can do is tread coffee, I suppose.