Questions on an unopened coffee bag that is 24 days post roast

#1: Post by **chanty 77** » June 13th, 2022, 7:35 pm

This isn't about freezing beans, so I know you all mean well, but not for me at this point, so please leave freezing out of your responses. To save on shipping the last several months, I have been ordering three 12oz. bags at one time of different favorite blends from my favorite roasters. I order the beans so they will arrive & are ready to use when I'm running out of the beans I have. This plan works for me. Since I don't typically open the first bag til it is 6-8 days post roast & it lasts me typically 8-9 days-- by the time I open the third bag it is around 24 days post roast. I really haven't noticed much in taste/flavor problems. What I DO seem to notice is that I am grinding fine, to begin with, but I end up using about 19-20grams of beans wherewith the first bag, for example, I use anywhere from 16.8-17.8g. They are all medium roasts. Could this be because despite not breaking the seal of the bag until I use it--it still has gotten more stale; thus the more grams of beans needed? Thanks.

#2: Post by **jpender** » June 13th, 2022, 7:47 pm

It's a very common observation that as coffee ages you need to grind finer. Using a larger dose will reduce the flow rate just like grinding finer will (at least until you are grinder too fine for even flow). So the most likely answer, and particularly since you aren't doing anything else to the coffee other than letting it get older, is that this is what you're seeing.

Why it's happening in a sealed bag is an interesting question. Perhaps the bag leaks or was sealed with oxygen already inside. Or maybe the aging is an anaerobic process. If it's the former then you might be able to combat it by repackaging in a hermetically sealed oxygen-free container. If it's the latter then your only recourse is... oh, well, for you there would be no recourse. :-)

June 13th, 2022, 7:57 pm

I'm not sure about bag leaks. This seems to be pretty typical with whatever company I've been using once I get to the 3rd bag at about 24 days post roast--so I'm thinking there are no leaks in the bags because I'd probably notice issues (which I don't) in the first and second bags. I don't know about the anaerobic process. From my understanding, is there such a thing as an oxygen-free container? I have an AirScape but heard that really isn't oxygen free.

#4: Post by **Ypuh** » June 13th, 2022, 8:23 pm

24 days is not stale or old. People tend to exaggerate a bit on freshness. You can notice it though, mainly due to crema and indeed needing to grind slightly finer. If you get to choose always pick the fresher bean, but don't throw it away or fool yourself that it tastes off by what you've read.

Most changes occur in the first week or so after roasting. I'd say in week 2-6 beans have usually settled and variance should be lower.

#5: Post by **Jeff** » June 13th, 2022, 8:46 pm

Shelf-life was tested and reported on at https://squaremileblog.com/2020/02/21/r ... freshness/

TL;DR is that the flavor definitely changes over a month in a roastery-sealed bag and that it is still drinkable at the end of the month, even by those in the trade.

#6: Post by **baldheadracing** » June 13th, 2022, 8:55 pm

June 13th, 2022, 9:01 pm

Jeff wrote:Shelf-life was tested and reported on at https://squaremileblog.com/2020/02/21/r ... freshness/

TL;DR is that the flavor definitely changes over a month in a roastery-sealed bag and that it is still drinkable at the end of the month, even by those in the trade.

Thanks, interesting article.

#8: Post by **jpender** » June 14th, 2022, 1:03 pm

chanty 77 wrote:I'm not sure about bag leaks. This seems to be pretty typical with whatever company I've been using once I get to the 3rd bag at about 24 days post roast--so I'm thinking there are no leaks in the bags because I'd probably notice issues (which I don't) in the first and second bags. I don't know about the anaerobic process. From my understanding, is there such a thing as an oxygen-free container? I have an AirScape but heard that really isn't oxygen free.

I really meant low oxygen, something at 1% or less. For example, the aluminum cans that Illy sells are flushed with nitrogen. And aluminum is essentially non-permeable to oxygen. Is the roaster you buy from purging their bags with inert gas? And what is the oxygen permeability of the materials in their bags? What about the "one-way" valves? It could be that all of your bags permit oxygen to enter slowly but still fast enough to affect the coffee. It could also be that they are packaged with a significant amount of oxygen.

At home you could vac seal coffee in jars. Something like a Foodsaver won't get anywhere near 1% O2 but you can buy higher quality vacuum sealers/chambers. Or invest in the Coffee Freshness System. That device uses CO2 as the "inert" gas. Apparently it works very well.

I don't know what goes on with coffee in the absence of oxygen. I'm just speculating that there are aging processes that don't require O2. To the extent that evolution of CO2 is a type of aging, does that stop if there is no O2?

That article from Square Mile was interesting. But one thing they said, without any evidence, sounds pretty questionable to me:

Square Mile blog wrote:Additionally, coffee loses density and moisture as it ages, so the longer the beans have been rested, the finer they will need to be ground to maintain a consistent brew time.

I just don't believe that a bag of coffee will give up moisture, not unless the ambient humidity is essentially zero. If any moisture works its way though the packaging it is far more likely to be moving in the other direction. And a density change?? What are they talking about?

June 14th, 2022, 1:18 pm

jpender wrote:I really meant low oxygen, something at 1% or less. For example, the aluminum cans that Illy sells are flushed with nitrogen. And aluminum is essentially non-permeable to oxygen. Is the roaster you buy from purging their bags with inert gas? And what is the oxygen permeability of the materials in their bags? What about the "one-way" valves? It could be that all of your bags permit oxygen to enter slowly but still fast enough to affect the coffee. It could also be that they are packaged with a significant amount of oxygen.

At home you could vac seal coffee in jars. Something like a Foodsaver won't get anywhere near 1% O2 but you can buy higher quality vacuum sealers/chambers. Or invest in the Coffee Freshness System. That device uses CO2 as the "inert" gas. Apparently it works very well.

I don't know what goes on with coffee in the absence of oxygen. I'm just speculating that there are aging processes that don't require O2. To the extent that evolution of CO2 is a type of aging, does that stop if there is no O2?

That article from Square Mile was interesting. But one thing they said, without any evidence, sounds pretty questionable to me:

I just don't believe that a bag of coffee will give up moisture, not unless the ambient humidity is essentially zero. If any moisture works its way though the packaging it is far more likely to be moving in the other direction. And a density change?? What are they talking about?

Thanks for all that. So far, I don't notice a dive in flavor, just needing to add more grams of beans. Now humidity is something that is a killer at times. We have NO a/c in our 1929 year old home, and today & tomorrow in Milwaukee, WI it is going to get over 90°. I can't wait to try & make espresso today & tomorrow. One day, Lord Willing, a home with central a/c.

#10: Post by **jpender** » June 14th, 2022, 1:55 pm

chanty 77 wrote:We have NO a/c in our 1929 year old home, and today & tomorrow in Milwaukee, WI it is going to get over 90°. I can't wait to try & make espresso today & tomorrow.

What happens with espresso in high humidity?

I've made coffee in Hawaii with the windows open but it wasn't espresso. The only thing I noticed was that there was absolutely zero need for RDT.