Should you freeze coffee in their sealed bags - Page 3

Discuss flavors, brew temperatures, blending, and cupping notes.
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Spitz.me
Posts: 1960
Joined: 14 years ago

#21: Post by Spitz.me »

CoffeeCoffeeCoffee wrote:There are some insightful quotes from Illy's book on oxygen level, temperature and thawing in the following thread (Posts #40 to 47)

Modified atmosphere for coffee storage at home

Below the most relevant examples :

SNIP

And also:
"The spoilage rate of roasted coffee increases seven-fold with every 10°C rise in temperature."

And here goes a last quote of Nicoli and Savonitti in Illy's book-to keep in mind when thawing beans :
"Cooled coffee beans should, however, be left at room temperature a few hours before grinding to trap the volatile aroma present in the cells in the oil and melanoidins; a large aroma loss at grinding might otherwise dull the flavour of the cup"
/EDIT
Thanks for these! Very interesting.

Soft language like "might otherwise" is definitely not something that anyone should take other than an opinion of what someone THINKS can happen.

I have not experienced a dulling of the flavour in my cup. To the contrary, anecdotally you can find many examples of people reporting better espresso from grinding frozen beans.

I should add - I'm not a super taster.
LMWDP #670

jpender
Posts: 3861
Joined: 11 years ago

#22: Post by jpender »

Good catch with the qualifying "might otherwise" phrase. It's always worth thinking critically about published statements, even when they come from what we tend to regard as very reliable sources. Illy is sort of a bible. But it's not always right.

For example, the line: "As CO2 is heavier than air, it tends to stratify at the bottom expelling most of the oxygen gas...". That isn't true in general. In the case of beans slowly off-gassing it's very, very unlikely to be the case. But it's in Illy so we give it credence, deserved or not.

belegnole
Posts: 440
Joined: 13 years ago

#23: Post by belegnole replying to jpender »

I agree; though CO2 is heavier than air and in the "correct situation" it would expel the majority of oxygen. However I haven't seen any coffee packaging ever that properly takes this into consideration. Nor have I seen any good documentation stating the overall volumes of CO2 off-gassed by the beans during say the first week post roast. So we don't even know if the beans could produce enough CO2 to replace the O2 in the container.

Also: "Cooled coffee beans should, however, be left at room temperature a few hours before grinding to trap the volatile aroma present in the cells in the oil and melanoidins; a large aroma loss at grinding might otherwise dull the flavour of the cup"

Wouldn't a volatile aroma be less likely to be lost when in a colder state? I've always read that they are released due to heat, not the reverse.
LMWDP #641

jpender
Posts: 3861
Joined: 11 years ago

#24: Post by jpender »

belegnole wrote:I agree; though CO2 is heavier than air and in the "correct situation" it would expel the majority of oxygen. However I haven't seen any coffee packaging ever that properly takes this into consideration.
I can't imagine any coffee packaging that would result in the density of CO2 being a significant factor in expelling the majority of O2. If the beans are packaged very soon after roasting you might get this result, but not because CO2 is denser than air.

belegnole wrote:Also: "Cooled coffee beans should, however, be left at room temperature a few hours before grinding to trap the volatile aroma present in the cells in the oil and melanoidins; a large aroma loss at grinding might otherwise dull the flavour of the cup"

Wouldn't a volatile aroma be less likely to be lost when in a colder state? I've always read that they are released due to heat, not the reverse.
It's a good question to ask. I would guess that the volatile aromatic molecules are more soluble in the oils/melanoidins at a higher temperature. But without seeing the source of this information it's just a guess. EDIT: Actually, my "guess" is probably a poor one as solubility usually goes down with increasing temperature.

Like @Spitz.me I haven't experienced a difference in aroma between beans that had been at room temperature for some time and beans taken straight from the freezer. I know I'm not the only one. So either it's a very minor effect, or one that only mattes with some coffee beans and/or some types of preparation, or maybe I just can't detect the difference due to my limited sensory capabilities. To be fair, I haven't done a careful, blind test. Maybe it's there if I looked closely enough.

CoffeeCoffeeCoffee
Posts: 76
Joined: 6 years ago

#25: Post by CoffeeCoffeeCoffee »

The authors (Nicoli and Savonitti) in Illy's book have done some thorough experimentation on bean staling so I believe that their opinion is worth considering, but as with any observation, it relies on a given set of factors (roast degree for instance, likely on the darker side in this case) and things may be different in other circumstances.

I should have noted that in the part about allowing the beans to sit at room temp for a few hours, they are not referring to frozen beans. As far as I understand, frozen beans are more brittle, this impacts the grinding process, and this may explain why some people get higher extractions with frozen beans.

Also, as with all the factors that do not have an huge influence on the results, it may be hard to spot a difference unless you have two cups side by side, especially if one wants to believe that what one is doing has/does not have an impact... And then should it have a minor impact it is up to decide you whether the contortion it requires is worth it or whether you would rather focus on things that have a bigger impact.

And to come back to the thread's topic: Yes, I think it is better to leave the beans in the bag they came with if 1) the bag is hermetically sealed, as an aluminium layer and is fitted with an one way valve and 2) your other option is putting them in jars without any further action (like vacuum or inert gas flushing). I am right now experimenting with small sized (convenient for me) jars that are flushed with CO2 and the first results (coming soon in the thread Modified atmosphere for coffee storage at home) are promising vs. a jar without any further processing.
The only criteria that really matters is how much you enjoy your coffee

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