Coffee is a semi-fresh product. If it's too fresh, it doesn't taste good. If it's too old, it loses intensity. In between lies the age that promises the most aroma and the best balance. But when and how are signs of aging noticeable? We tested this with our coffees: Leica, Henrique and Dreispitz under the microscope.
Since 2019, we recommend on our coffee packages that the coffee should be consumed between two weeks and two months after roasting. This is a recommendation because we think the coffee tastes best during this time span. At the same time, we know that our customers drink the coffee rather quickly and don't stockpile it. So we believe that a majority of our customers drink our coffees between one and three weeks.
But: Why doesn't fresher coffee taste even better? Does the coffee remain stable between 2 weeks and 2 months after roasting? And is it undrinkable after that?
We checked our recommendations with three coffees from our selection – with the Leica, the Dreispitz and the Henrique. The coffees reacted differently to aging. Let me first explain why coffee ages.
Why does coffee age?
Coffee ages because it's still alive. More precisely, because even in dried green coffee there is still moisture present (often between 9–12%). The embryo in the green coffee is dormant, but still capable of germination. Green coffee is theoretically still viable for a long time, but once it's roasted, the clock starts ticking rapidly.
We always talk about aging, or signs of aging, but never about spoiled coffee. Coffee becoming undrinkable for health reasons would have to do with extreme storage conditions – high humidity and eventually mold – of course that's not recommended. Not many people would eat moldy bread either. Old coffee, however, doesn't endanger health; rather, it simply fails to meet our expectations of what we understand coffee to be.
Analyzing coffee sensorially and chemically presents special challenges because coffee is always a moving target (Beeman et. al, 2011). Coffee is inherently unstable; it changes especially rapidly after roasting. Thus sensorial and chemical analyses are always time-consuming because the object of study constantly changes – coffee is alive, even after roasting.
Various physical and chemical reactions during roasting change the structure of the coffee bean and are co-responsible for the coffee aging. Roasting makes the bean more porous and causes it to lose volatile compounds (mostly aromas) more quickly. Maillard reactions during roasting create compounds that in turn are susceptible to fatty acid oxidation.
We know these fatty acid oxidations as rancid coffee. Many of us have already opened a pre-ground coffee package that had been hiding somewhere in a cupboard. A rancid smell comes wafting out. Grinding massively accelerates the aging process because grinding potentially increases the surface area of the coffee.
What factors cause coffee to age?
There are mainly two reasons that cause roasted coffee to age faster or slower. They are packaging and storage temperature.
Coffee packaging
Coffee packages are becoming increasingly colorful, creative and thus more eye-catching, but the main task remains the same: keeping roasted coffee fresh. Basically, coffee can be packaged in a paper bag if it's consumed very quickly. If forced aging is the goal, roasted coffee can be stored openly.
If roasted coffee is to be stored, it needs an oxygen barrier. These are usually polyethylene layers (PE) on paper, or aluminum packaging. Aluminum has shown the best properties for keeping coffee fresh for a long time – however, aluminum is something we decided against for ecological reasons. We chose PE-coated paper. This keeps the coffee fresh for a shorter time than aluminum, but because we don't sell it on supermarket shelves, the duration from roasting to consumption is much shorter.
In supermarkets you find almost exclusively aluminum bags that are even flushed with nitrogen. These coffees must not show overly obvious signs of aging for several months. The aluminum-nitrogen combination currently performs this task best. Transparent coffee packages are visually interesting but allow UV light to penetrate and accelerate the aging process.
Storage temperature
We know that higher temperatures accelerate chemical and physical reactions – and vice versa. Since roasted coffee is still a constantly changing product, the external condition of high temperature can cause the coffee to age faster.
Aroma compounds are forced out of the packaging more quickly by high storage temperatures, as is the still present CO2 created during roasting, which keeps the coffee fresher in the package. While that smells good in the moment, it tastes less good in the cup.
The opposite is also true – coffee doesn't need to be stored too cool. If coffee is stored in the refrigerator and then brought back to room temperature for use, the condensation that forms leads to faster aging, but especially to uneven grinding distribution.
Michel discussed this in a short video:
Yeretzian and Blank examine these factors closely in their publicly accessible paper: Protecting the Flavors – Freshness as a Key to Quality. We also made a video with Chahan Yeretzian about how long coffee can actually stay fresh.
Why doesn't fresh coffee taste good?
In a coffee that was roasted only a few days before, the amount of CO2 is still very high. While this does produce a nice crema, a visual feature that many coffee aficionados seek, we've described exactly what the crema myths are about here.
This CO2 in high concentration, however, prevents a high extraction rate. In short: the CO2 behaves in coffee like a waterproofing spray for shoes. It keeps water away, but under heavy load the shoe also gets wet on the inside.
Coffee that still has lots of CO2 is enveloped by it. Water can extract less from the coffee during extraction because it "beads off" the CO2. We still owe you a detailed examination of this.
During extraction, the brewing water first dissolves acids from the roasted coffee. Backyard Coffee illustrated this nicely in this video. So shorter extractions are always acidic because the contact time was very brief. Now if we think of our "waterproofed" coffee with this CO2 coating, the following happens: the water penetrates less intensely into the interior of the coffee bean, so what dissolves most easily is extracted: the acid.
Fresh coffee always has an intense, full crema, but tends to be acidic and has less texture, since this (sugars and fibers) can only be extracted through longer extractions, or when the CO2 is mostly no longer present.
How does old coffee taste?
Of course this has to do with individual taste preferences, but rancid coffees are a pain for many. I was once invited to a sensory panel at Nespresso where we tasted capsule coffee up to five years old. I was amazed at how sensitive the Nespresso staff was in detecting even the slightest signs of old coffee that I wouldn't have considered old yet. The Nespresso sensory experts are extremely well trained in detecting rancid coffee.
"Rancid", as already mentioned above, is often a description for old coffee. We know this from oils that have gone stale. Describing rancid is not quite easy – we often use loan words like: Staleness, stable, dull, woody, sharp – what else comes to mind for you? Feel free to share your descriptions in the comments.
Old coffee, in our experience, generally has the property that:
- the aroma is masked by foreign notes (such as rancid, staleness, woody, tallow-like)
- the flavor notes are no longer intense, and if they are, not as originally perceived (fruity, floral)
- the texture may be less round
- the acidity stands alone, because the degenerating sweetness can probably no longer support it
- balance is no longer present; acidity and bitterness often dominate
- the aftertaste can seem woody
- Yannick Schilli from the sensory group on FB speaks of "coffee without tension"
More about freshness and other criteria in coffee are discussed here.
When do our coffees taste best?
With this knowledge, we wanted to examine three of our espressos more closely. We tasted the coffees over 12 weeks at two-week intervals.
The experiment setup was as follows:
- Tasting after 2w, 4w, 6w, 8w, 10w, 12w
- Extraction: 19g coffee grounds, 47.5g extraction amount (1:2.5) brew ratio
- Target time: 27 to 30 seconds
- three extractions per coffee at each tasting
- consistent tasters
Leica Espresso
A honey espresso from Finca Santa Rita in Nicaragua. A special coffee for us because it was the first specialty espresso from our own farm, and we've managed to develop a standard process. We're trying to produce more Leica every year. Fruity like cherries, lots of sweetness and a soft texture characterize this coffee.
| Time after roasting | Comments |
| 2 weeks | Notes of lime, medium weight, zesty acidity, limited sweetness, limited balance |
| 4 weeks | very round, balanced, concentrated, syrup-like sweetness, creamy |
| 6 weeks | Limited aroma, pleasant soft and creamy texture, dense, dominant acidity, bitter aftertaste |
| 10 weeks | Few intense flavor notes, coating on the palate, good texture, pleasant, somewhat simple acidity |
| 12 weeks | Amarena cherries, no roast notes whatsoever, silky, thin texture, slight saltiness, bitter aftertaste, qualitatively pleasant acidity, not further specifiable |
Comments on the Leica tasting
The coffee at four weeks was our favorite. By three weeks, it's already at its peak, which then lasts for about ten days. When the coffee is very fresh, acidity dominates. At about three weeks after roasting, the balance is there, the fruity cherry notes are present, and the sweetness is significantly more intense.
The aroma then dissipates faster after six weeks, before – interestingly – reappearing after 12 weeks with great clarity. However, the three-month-old coffee lacks the soft, dense texture that espresso is all about for us.
Leica drinking recommendation: at its peak after 20 days
Dreispitz Espresso
Our signature blend for all espresso lovers. Balanced and straightforward for all common brewing methods. A full-bodied, chocolatey espresso, carried by a creamy body and a fine acidity.
| Time after roasting | Comments |
| 2 weeks | dark chocolate, limey acidity, pleasant robusta note, very round, pleasant aftertaste, full body |
| 4 weeks | medium texture, somewhat watery, subtle acidity well integrated (simple but clean), clean robusta aftertaste |
| 6 weeks | intense robusta notes, long robusta aftertaste, strong, well integrated acidity, simple but clean; creamy-heavy body |
| 10 weeks | Age-mild espresso where the acidity has a stronger effect. Somewhat fragmented, rather light, robusta notes integrated again, balanced, becomes more intense when cooled. |
| 12 weeks | Little aroma, scent light like natural robusta, texture present, sweetness lacking, robusta winininess. Lacks intensity and balance of attributes. Like a marathon runner who sets off and falls down. |
Comments on the Dreispitz tasting
The coffee at two weeks was our favorite. It then holds up well for a week before the texture declines somewhat. Those who prefer stronger robusta notes should be well served after six weeks. The flavor changes in such a way that the coffee from Nicaragua fades somewhat into the background and the robusta takes over. An interesting interplay that we also really experienced intensely for the first time.
Dreispitz drinking recommendation:
1st peak: after 12 days
2nd peak: after six weeks
Henrique Espresso
Henrique from Brazil is the chocolatey-nutty espresso with full body and long aftertaste. As an espresso a bonbon, with milk a dessert. This one can do something, this Henrique. And it has punch.
| Time after roasting | Comments |
| 2 weeks | very dark hazelnut, medium texture, roast notes noticeable, little acidity |
| 4 weeks |
very harmonious, balanced, defined, mild acidity (delicate), very dark chocolate, almond notes |
| 6 weeks |
very dark chocolate, bright acidity, more intense roast note, age is becoming somewhat noticeable |
| 10 weeks | somewhat fragmented, medium weight. Notes of licorice to classically dark chocolatey, slightly roasty in the aftertaste |
| 12 weeks | no longer coherent within itself. Faster extraction: 19g in 40 out in 24 sec Loss of density, clarity, sweetness, A shorter extraction benefits old coffees |
Comments on the Henrique tasting
The Henrique is one of our darkest espressos, which is reflected in the taste. The roast notes are present, especially after two weeks. After three to four weeks, the coffee is at its peak – it's balanced, the roast notes are gone and give way to the chocolatey notes. After ten weeks you can already feel the age in the coffee somewhat, the balance is not as high as at the beginning.
Henrique drinking recommendation: at its peak after 20 days
What is the optimal age for roasted coffee?
We like it this way:
Filter coffee:
at least 7 days after roasting, 10 days is better, for naturals and other intense fermentations wait rather 12 days
Espresso:
at least 10 days after roasting, for light roasts about 14 days, for naturals wait rather 21 days
When is coffee too old?
Counter-question: what is too old? We recommend consuming our coffees between two weeks and two months after roasting. That's our idea of how the coffees should taste. Anyone who stays outside this time window is not making a mistake, but rather following their own preferences.
In our long-term test, it became clear that our coffees in non-aluminum packaging show the first signs of aging after about 10 weeks, so beyond our two-month recommendation. But there are also always surprises, such as the Dreispitz, which after an initial peak and a subsequent decline recovered and is at its second peak after six weeks.
Can coffee get too old? Yes, if it's no longer sensorially enjoyable. Old coffee, however, has no negative impact on health. The rancid, staleness, tallow-like notes can take over; the lighter notes, especially floral ones, fade away. But we're not talking about a defect here, rather a normal aging process.
Coffee, unlike wine, has a very small enjoyment window. Wines, on the other hand, can improve with age. Coffee is thus something like Snapchat, simply for taste. Wine is more like the YouTube video that becomes more important with age.
