I couldn't find any conclusive agreement on this subject.

I bought some 49th Parallel Epic Espresso in a valve bag a while ago and the Cafe owner told me the coffee hits its peak at about 1 month past roast date because the bag design slows down the oxidation process.

Hmmm...sounded funny to me. I always heard 3 weeks past roast was the longest it would last.

What's the longest time you can keep coffee in a good opaque valve bag (at room temperature) before you need to throw it out?

For me a month sounds a little too long. Each bean is different and then there is roast level etc etc. I use these bags and squeeze out the air and for my tastes most beans are good from 5 days and usually drop off flavor and espresso appears thinner and blacker after 12-16 days. As already stated there are variables but i have yet to enjoy any bean much after this time limit.

This is a very good question that I'd be interested in seeing some good research on. My own limited experience is that that unopened valve bags are kind of on par with freshly frozen (and tightly sealed) coffee. It can keep for quite a while and still be quite impressive when opened weeks later, however, it fades much more quickly. It's like watching one of those rapid CGI-managed aging sequences when a character's immortality is finally undone.

I think that kind of a freshness hysteria is going on here.

Up to 3 months storage in a valvebag is fine with me. A lot of coffees need some time to develop.

I would never drink my self-roasted coffees which I store in porcelain jars earlier than four days after roasting.

The coffees from a very good roaster here in Germany are delivered in valvebags and alwas VERY fresh - TOO fresh. They are best after three to four weeks, everything earlier would be wastage.

I think its better to keep the CO2 in the valvebag instead of squeezing the air out - you lose a lot of aroma.

Ernie wrote:I think that kind of a freshness hysteria is going on here.

Up to 3 months storage in an valvebag is fine with me. A lot of coffees need some time to develop.

I would never drink my self-roasted coffees which I store in porcelain jars earlier than four days after roasting.

The coffees from a very good roaster here in Germany are delivered in valvebags and alwas VERY fresh - TOO fresh. They are best after three to four weeks, everything earlier would be wastage.

I think its better to keep the CO2 in the valvebag instead of squeezing the air out - you lose a lot of aroma.

Thanks for providing another perspective. The Barista I talked to was also convinced the coffee in the good valve bags peaked at around 1 or even 2 months. I'm still not sure but would like to try and find what the general opinion is on the subject from the actual roasters (or an expert taster).

You can drink your coffee however you like and if 6 months stale is fine with you okay.


Valve bags don't preserve freshness. Valve bags allow you to ship fresh without the bag exploding. Oxidization isn't the only thing that stales coffee.

Everyone has a different preference. I love the taste of freshly roasted coffee and generally toss it out after a week or two, when I consider it stale. However, flavors change and develop as time goes on and coffee oxidizes. It depends what flavors you like. Some people will like the flavors after two weeks, a month or more. Some people also enjoy freeze-dried coffee. They are all different flavors and to each his own I say.

Adrian

Adrian got his post out wile i was typing so this may look familiar.

I think when a coffee "peaks" is very subjective, since it is a matter of taste.
I think we can agree that over time no matter how you store the roasted beans the flavor profile will change.

My experience has been that the window of opportunity for espresso is much smaller than for press pot.
To me while the the mouth feel and crema seems to diminish during the first 2.5 to 3 weeks it seems to do so significantly faster in the 4th week, kind of an exponential decay. Also flavors seem to appear and subside during the first 2-2.5 weeks but from that point the start to disappear or flatten to the point that it is not "to me" usable for espresso.

Now my wife and I will still drink this coffee but as press pot. While much of what I said above still holds true for my roasts as press pot, the coffee is still very acceptable for a longer period of time. There are a couple of beans I like better a little "aged" for press pot some of the Colombian's I have roasted come to mind. I did a batch that at 5 days just wasn't for me. A couple weeks later I missed a roast and was running short (at 5:30am something is better than nothing) and that batch was still in the back of the cupboard low and behold it was a very different coffee. However while I have not tested this i can't imagine you would still get the wonderful blueberry flavors from a Harar if you left it in a sealed bag for 6-8 weeks, they seem to fade faster than that.

As far as squeezing the bag what you are smelling has already left the bean and would never make it to your cup. I would be interested to know the science behind whether the higher concentration of CO2 in the bag would slow the decay of delicate flavors.

49th Parallel flushes their bags with nitrogen which might help with a longer shelf life. In my experience, coffees in valved bags can still be great after 4 or more weeks right after opening. However, I've always found that they also fade quickly as soon as they are opened.

A local roaster nearby purposefully ages their coffee 6 weeks in valved bags before sending them to wholesale customers. It was explained to me that this was to make the coffee more stable for their customers (less need for them to adjust their grinder). I wouldn't classify most of their clients as "third wave" type shops.

Cheers
Kaelin

Valve bags flushed with nitrogen, etc. will prevent a lot of oxidization since there is little oxygen in the bag. There are three processes going on with coffee and they compete with each other as time goes on.

First, coffee loses CO2, degassing as time goes on. Generally, this subsides after a few days, but coffee is felt to be better after a rest owing to this.

Second, coffee flavor components decompose by non-oxidative processes. The reductive chemistry of aromatic and tannic molecules generally adds complexity and improves flavor. Look at Pu-Ehr Tea or Red Wine for the precedents here. Thus, coffee generally improves with age.

Thirdly, coffee oxidizes and goes bad acquiring the sour, stale flavors. This process depends on oxygen and the presence of the molecules from Process #2.

THUS, usually coffee gets better with age, but oxidation makes it intolerably stale at some point. Aging roast coffee in nitrogen-flushed bags will allow it to go much further. It is just like how the corked bottle lets wine age properly rather than turning to vinegar.

What you want to do is make sure the bag or container you store the coffee in is flushed with nitrogen. You can usually find this in industrial tanks or buy it as a "wine saver" spray.

Adrian