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It’s time we retired our obsession with roast dates

A few thoughts on freshness, a bit of science and some ideas about how we can improve the freshness of our coffees.

One of the unique selling points of specialty coffee roasters is that they always freshly roast their finest coffees to ensure their customers get the very best experience and flavour.

As the owner of a coffee subscription company, I often get asked by my customers how fresh the coffees that I put into my coffee boxes can possibly be by the time they arrive at their destination and some people occasionally voice concerns that if their boxes are in transit for too long that their coffees will be old and stale.

In this article, I want to address these concerns with insights from my own research into this matter and provide some guidelines on resting and storing your coffees so you get the best flavour experience possible while encouraging you to leave unnecessary worries about freshness behind.

Let’s start at the beginning. From green coffee to finished product.

When we talk about freshness, we can refer to a lot of different things. How fresh the crop is, when the coffee was roasted or when the coffee was brewed. Indeed, freshness has become such an important selling point in the specialty coffee industry that it can easily lead to unnecessary worries and waste because research and new scientific insights have moved forward faster than consumers have changed their perceptions.

That is why I want to start at the beginning to set the scene.

During the roasting process when volatile compounds inside the green coffee are heated, a series of chemical processes are set off that turn sugars and amino acids into carbon dioxide (CO2) and as this happens, energy is released. This process removes moisture from the green coffee, making it more brittle and as the surface of the beans begin to crack, the gases that are trapped inside are able to escape.

Once the roasting process is completed and the beans have cooled, they are most often stored in vats or containers for a day or longer to allow some of the remaining gases to continue escaping, a process that is called de-gassing. This is an ongoing process that will continue long after the beans have been bagged and will not be completed until you have ground and brewed your coffees.

It’s therefore very important to rest your coffees sufficiently because coffees that still contain a large degree of CO2 will taste comparatively sour and cause many issues in the extraction process, in particular when trying to pull espresso shots as this can lead to channeling and severe inconsistencies that will require constant calibration and leave baristas cursing their grinders and machines.

This is why roasters like La Cabra and The Barn nowadays leave their coffees to rest for up to six weeks by which time they say their coffees will have stabilised sufficiently before they are served as espressos in their own cafés. However, home baristas don’t need to do this per se and I don’t suggest that you should put your bags aside for a few weeks after receiving them.

Coffees that are sealed inside airtight bags shortly after roasting will continue de-gassing inside a protected environment. The one-way valve found on most coffee bags ensures that any CO2 that is being released from the beans can push out any trapped oxygen (O2) without letting any of it get into the bags from the outside. 

Oxygen: The primary enemy: Oxidisation leads to not only loss of freshness

As a result, there is little reason to be concerned that your coffees will be stale or old by the time they reach you, even if there are a few weeks in between the roast date and you receiving them. 

Furthermore, since all of the roasters that I work with are great masters in their trade and roast their coffees light to medium, the coffees keep even better as was confirmed to me by Scott Rao, a leading coffee consultant and expert who said: “Many of us in specialty coffee are aware that a light roast can taste great a month or two after roasting.”

Coffees that are roasted dark don’t keep so well because they are more porous than light roasted coffees and are therefore more susceptible to fast degradation. Furthermore, very dark roasted coffees will have a substantial coating of natural oils that build up on the surface of the coffees and their exposure to oxygen can quickly turn a coffee rancid as the oxygen impacts the oil. A similar process can also be seen with olive oil. If you don’t store it properly, it’ll turn rancid quickly.

Proper storage is the key

Rather than fretting about a coffee’s potential deterioration during a few days of transit, we need to pay much closer attention to proper storage of our beloved coffees because that is where things often go wrong.

The fact of the matter is that coffee begins deteriorating once it comes out of that roaster simply because the heat changed the beans’ chemical composition from raw material to finished product and its altered state makes it more susceptible to degradation.

However, once a coffee is bagged up and kept inside a protected environment, this degradation can be severely limited, even more so if all the oxygen is taken out of the bags after they are sealed. Sometimes, when bags travel on a plane, the pressure difference acts like a vacuum packer. This won’t, however,  stop the beans continuing to release CO2 over time.

Yet, the big mistake is often made when people open their coffee bags and then either leave them open by accident or keep opening and closing them as they brew their coffee over the course of a few days or weeks. If you work in a busy café pulling lots of shots you won’t encounter much degradation as the coffee beans will be finished quickly but for home brewers this certainly poses a risk.

Many people have been talking about freezing their beans or portioning their beans into small pouches, vacuum packing them and then freezing them to keep them fresh for longer but lately, this theory has also lost popularity.

It’s easy to get swept up in trends that one sees on social media but it’s vital that one understands the science first.

Environmental protection

While doing my own research on this subject, I came across an article written by coffee roaster and coffee journalist Antony Watson who discussed freshness in coffee in a long piece entitled ‘Preserving Freshness: A Race Against Time’ published in the SCA magazine. 

After contacting him for some clarifications, he said: “As we know, coffee is a dynamic and intrinsically unstable product – only cooling to a temperature as low as -40°C, can be a successful strategy to help preserve freshness (i.e. a strategy that is out of the reach of most people unless you have a science lab).”

He went on to list the four key environmental factors that can severely impact a coffee’s freshness:

Temperature: This is the main driver of loss of freshness (e.g. Arrhenius equation) and will accelerate the physical and chemical changes in coffee the most. Studies have shown that a 10°C increase can result in 50% loss of shelf life. That is why it is important to keep coffee cool.

Moisture / Humidity: Studies have also shown that higher water activity accelerates all those flavoursome moisture compounds and leads to shorter shelf life / freshness (i.e. don’t store coffee in a fridge).

Oxygen: The primary enemy: Oxidisation leads to not only loss of freshness (i.e. loss of volatile organic compounds or VOCs), but also the formation of new off-flavours (i.e. rancidity).

Time: The longer the roasted coffee goes from the point of transformation, the more it is susceptible from the processes highlighted above. But we can slow down the process by making smart choices.

All of the roasters that I work with employ strict quality control measures during sourcing, roasting and packing, I am confident that their coffees will reach my customers in the best possible condition but at the same time, given that my customers are spread out across several continents with vastly differing environmental conditions, it’s impossible to make one recommendation that applies equally to everyone.

Tasting 1 year old coffee

I recently conducted an interesting experiment with some coffees that were returned to my warehouse a year after sending them off to a customer in the Middle East where they got stuck at customs and were then returned for no reason.

I wasn’t sure what to expect since I had never worked with coffee that was roasted so long ago and yet came to me in pristine condition. After opening the bag, I detected a sweet yet slightly muted aroma, somewhat an indication that this coffee had started to loose its freshness despite being sealed airtight for 12 months.

During the brewing process there were almost no bubbles rising to the top of the coffee bed during the bloom, another indication that it had de-gassed enough to part with most of the CO2 and the cup profile itself was balanced, clean and really smooth but lacking in vibrancy and outspokenness, often an indication of old coffee.

[…] the coffee’s freshness depends just as much on our own handling of it as it depends on the roasters […]

For me, this was testament to the fact that coffee can still taste solidly good even one year after roasting but that it wouldn’t score very high on a cupping table and therefore not necessarily be interesting to specialty coffee lovers while at the same time proving to me that older coffees should not automatically be discarded simply because they were roasted long ago. 

If the raw material is great, the roasting and packing was done to the highest standards and the coffee was stored properly, old coffee can still offer a tasty cup of coffee. If this idea becomes more widely accepted, we might even find ourselves buying specialty coffee in supermarkets more regularly, although most roasters will argue that it’s not in their interest to sell older beans. And I understand why.

In conclusion

One of the most important conclusions I want to draw is that we don’t really need to be quite so obsessed with the roast date as we were told to be a few years ago. When specialty coffee first stated to break out, we were were taught that the finest coffees had to be consumed just days after roasting as they would otherwise go stale. 

In fact, I recalled a Kickstarter project from some years ago that got quite a bit of attention because it was a device that roasted your coffees to order, similar to an Ikawa I suppose, and then ground and brewed your coffees shortly after. While some people got pretty excited in the beginning by the prospect of having full control over their coffees, the project quickly faded away as people realised that the coffee simply wouldn’t taste good due to a number of unsurmountable flaws in the design of this device. 

As our understanding of the actual chemical processes that affect a coffee’s cup profile becomes more advanced and we gain more knowledge, we are learning to appreciate that proper resting can be just as beneficial to coffee as it is to wine. 

More importantly, we need to comprehend that the coffee’s freshness depends just as much on our own handling of it as it depends on the roasters doing a good job at roasting and packing the beans for our consumption.

Indeed, there is little point in putting so much emphasis on pouring techniques, water composition and brewing recipes if we don’t attach the same importance to proper resting and storage of our coffees.

Based on everything I’ve learned so far, my recommendation therefore is to give our coffees a couple of weeks to sufficiently rest (usually by the time my boxes land on your doorstep, they will be just perfect) and to use air tight containers or vacuum pack your coffees into pre-portioned pouches and keep them in a dry, dark and cool place. There is really no need to stuff your freezer with coffee.

Now I’d love to hear what you think. What is your own position on this and how do you handle your coffees once you’ve bought or received them in the mail?

Share your thoughts down below.

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Luke
Luke
2 months ago

nice article! I roast and have been freezing my coffee in small medical tubes for the last 10 years since before it became “trendy” and it works great 😊! But.. I’m not freezing at -40 so I can have it in 10 years. I freeze so I can enjoy in the next 6-12 months when I feel like drinking some a little different. Cheers,
Luke

Alper Tengüz
Alper Tengüz
2 months ago

Thank you for this comprehensive summary.
So should I put my beans in the fridge at least?

It’s time we retired our obsession with roast dates

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