Not sure i follow Arpi. She froze both zip and valve and left at room temp both zip and valve.
The frozen zip and valve scored worse than the non-frozen ones.

yes but there was a difference between frozen zip and frozen valve bags. She herself points out that it due to a difference in porosity. And valve bags are also porous (imperfect). She needs to use next a good vacuum bag before she jumps to other conclusions.

Cheers

I think before focusing on bags she needs to figure out how 2 week old ground coffee beat whole bean. That result throws everything else into doubt.

I agree.

I'll wait till next experiment

jasonmolinari wrote:I think before focusing on bags she needs to figure out how 2 week old ground coffee beat whole bean. That result throws everything else into doubt.

I'm surprised too, but Experiments with Preground Coffee for Espresso and a Brew Pot did report similar findings for less extreme preground vs. freshly ground brewed coffee:

Abe Carmeli wrote:So, with that in mind, we designed two experiments: In the first one we essentially repeating Scott's experiment. We pre-ground a batch of 2 day old Geisha Esmeralda (Jim's roast) and waited 12 hours. We then brewed it in the Eva Solo (soak Pot) for four minutes at 198 f 8 oz water and 13.6 grams ground coffee. At the same time, we freshly ground the same coffee and brewed it side by side in another pot.

The result was unanimous: The pre-ground coffee was sweeter, and as a whole better integrated. It still had all the high notes that I thought may get lost somewhat in 12 hours, and it was somewhat rounder.

Interesting.

I think that there's some info missing from her experience. Like how they let the beans warmed up. I found that freeze bean will lose a lot of aroma after 8-12h. And I found that directly grind (but I don't think it's good for the burrs...) or wait 2-3 hours give the best result.

As I did today with epic 49th parallel. No difference from fresh and it was ground 45minutes after post chilling.
Same for 49th Kenya AA Kingaoi in french press..

Do what works for you folks!

if you think frozen beans degrade after 8-12h.. how much do you defrost at a time?
do you take the beans to be used out of a larger sack of frozen beans (taking the larger sack in and out of the freezer often) or do you freeze many smaller portions to be taken out of the freezer only once and thawed?

HB wrote:I'm surprised too, but Experiments with Preground Coffee for Espresso and a Brew Pot did report similar findings for less extreme preground vs. freshly ground brewed coffee:

Big difference between 12 hours and 14 days, wouldn't you agree? The results reported by Scott and Abe are far less contentious.

This is uninterpretable, as is the first "experiment." Earlier comments have focused on some of the seeming contradictions present, and I won't repeat them.

Some details are given regarding the coffee storage and preparation, but essentially nothing about the tasting, the "data analysis," and how conclusions were reached. This sounds like it took half an hour or at most an hour to do.

Anyone who has ever participated in a real blind tasting knows that properly done, it is arduous work, and that differences tend to be subtle unless the samples are hugely different. The power of suggestion is enormous and must be carefully avoided. The writeup suggests that this whole thing was simple to do and akin to comparing a McDonalds hamburger to piece of Kobe beef.

The results are (largely) counter intuitive and contradict the everyday observations of many people on this site. And as previously stated, the conclusions appear to have been already arrived at before the "study" was executed.

ken