- Physically, coffee beans do not expire and thus it can have an extended shelf life, especially if stored appropiately.
- However, the intensity of coffee flavors decline with the time.
- To get a good brew, coffee needs to rest for a couple of days so that coffee flavor compounds can be properly extracted.
- The rest time of coffee after roasting can be as long as 4 to 12 days. It is not recommended to prepare coffee directly after it had been roasted.
- Knowing the roasting date allows you to assess the days it need to rest to get a better extraction.
...if you have time, dive deep into the full article
I assume that we all love fresh coffee!
Freshly roasted, freshly prepared or simply freshly served.
I think that we all agree that fresh foods are what most people are looking for when walking through a supermarket and especially when you visit a local farmer’s market. And they have a good reason to look for fresh foods.
Usually, they taste and smell better and have a great texture.
But what if I tell you that freshness really depends on the kind of product you want to buy. In fruits or vegetables, I think, there is no doubt that freshness is imperative.
But what about roasted coffee? Does it really have the best aroma or taste when it has been just dropped out of the roasting drum? And what does freshness really mean regarding roasted coffee?
What does freshness for roasted coffee mean?
First off, we have to create a common understanding of what freshness refers to and how we can use it for coffee.
When you ask me about “freshness”, I would simply say that it refers to a status or moment of a food or a raw material which is close to some kind of original state. Fruits or vegetables which are sold on a farmer’s market, for instance, are usually regarded as very fresh because the date of harvest is very close to the moment the product is offered to you.
Now, how can we apply this to roasted coffee? Freshly roasted coffee usually means that only a few hours or days have passed since the coffee had been roasted and dropped out of the drum.
At that moment, it is great to perceive the incredible aroma complexity. In specialty coffee and in small-batch roasting ventures we have become fairly obsessed with offering the freshest coffee and taking advantage of the appeal of “freshness”.
As a consequence, customers might think that the closer the coffee is prepared to the roasting date, the best it is in terms of flavors. This sounds quite obvious as it also copes with our general understanding of what fresh foods or drinks should be like (see above).
But coffee is a little bit different.
Recently, I have read a great interview with Professor Chahan Yeretzian who is head of the Center for Analytical and Physical Chemistry at Zurich University, and is also a member of the Specialty Coffee Association of Europe’s Board of Directors. He talks about the myth of freshness in coffee and asked what it really means. As a result, there are basically two ways to see freshness in coffee:
- From an aroma perspective and
- From a CO2 perspective
To understand this and how it impacts coffee brewing, we have to take a short break and dive into the roasting process itself.
Regarding the aromas, most of them are created during the roasting process by a chemical reaction called the Maillard reaction. Don’t worry, I won’t step into chemical details here, since I am not a chemist, but it is essentially the same reaction which occurs when you toast bread or make “caramelized” onions for your burgers.
These aromas are great and as soon as the coffee beans leave the drum we can perceive them all at once. But from this point on, the aroma intensity starts to drop which can happen very fast. This all depends on how proper you store your coffee. But that’s another post ;)
Another thing which occurs during the roasting of the beans is that carbon dioxide (CO2) is created which starts to “leave” the beans. This is called degassing and it is the real crucial point when it comes to brewing coffee.
How does degassing affect coffee brewing?
Well, imagine you take the beans shortly after roasting. At that point, they are degassing pretty “aggressively”. Grinding the beans will accelerate degassing.
Now, in order to get coffee flavors extracted from the small coffee particles, water has to penetrate the particles. But when these particles are surrounded by gas due to degassing, water won’t penetrate the particles properly.
Consequently, you might get an under-extracted coffee (fewer coffee flavors are extracted) which leave you with a sour taste and often a dry mouthfeel.
So, Professor Yeretzian argues that while there is the aromatic freshness which is probably at its peak shortly after roasting and is an important factor to specialty coffees, there is this kind of CO2 freshness which is crucial for brewing.
By storing the coffee properly we try to keep the aromas fresh over time. Regarding degassing, we try to age the coffee to a sweet spot or a moment when it allows extracting best the coffee flavors and where the outgoing gas does not interfere with the flow of water to the particles.
Why is the roasting date important?
In this context, the roasting date becomes important because it allows you to measure, analyze and try when coffee is at its peak, i.e. the best moment to brew it.
It might be best to ask your roaster about this because he/she has the experience with a determined coffee and roast profile.
The expiration date is only a poor indicator when it comes down to freshness. The reason is simple: coffee does not physically expire.
If you open a bag of coffee after one year, you will not have something that is completely degraded or not recognizable. The beans are still there. Most likely all of the aromas will be gone and depending on how the coffee was stored it went stale.
- Try to find out the roasting date of the beans
- If you have the availability, try to brew the beans throughout different days (no matter which brewing method you’re using) to get a notion of how much time the beans have to rest, there is no standard rule, each coffee and roast differs. Especially if you have a coffee shop, this becomes vital to become consistent. Sometimes this can take 4, 7 or 10 days.
- Expiration dates do not matter in determining the coffee’s flavor quality
- Store the coffee properly especially for maintaining the aromas
- Buy small quantities and consume them in an appropriate amount of time so you can get the best flavor. Control how much coffee you need over a certain time period.
Let’s wrap it up
The roasting date is your starting point to determine how many days your coffee should rest to get a nice flavorful brew. The expiration date does not really tell you what you need to know and is often a legal requirement in the food sector to put on a bag.
Aim for freshly roasted coffee and experiment with the rest time so you can get the best out of the brew by reaching the flavor peak. Don’t worry if this takes 7 or 12 days after brewing. The question how long to degas coffee beans really depends on the specific coffee and the roast profile.
Bear in mind that this is only one of many factors which affect coffee flavor in the brew. But I wanted to address it here because I feel that many people get confused about this topic. Finally, let the taste and aromas be your final judge to determine when the coffee is best for you or your customers.
So, stay caffeinated
I hope you liked this post. Tell me your experience about fresh coffee and how many days are you waiting to brew a cup after roasting? Leave me a message below.
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5 Incredible Myths Of Coffee Freshness, Revealed (2015, September 23). [Blog] Sprudge. Available at: http://sprudge.com/5-incredible-myths-of-coffee-freshness-revealed-86011.html (Accessed on 2017, July 24)
Title picture by Daniel Ruswick on Unsplash
Corrected & Revised by Andrea Letzner