Coffee is a semi-fresh product. If it's too fresh, it doesn't taste good. If it's too old, it loses its intensity. Between these ages 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.
Since 2019, we've recommended on our coffee packaging that coffee should be consumed between two weeks and two months after roasting. This is a recommendation because we find the coffee tastes best during this time frame. At the same time, we know that our customers tend to drink their coffee quickly and don't hoard it. Therefore, we believe the majority of our coffees consume between one and three weeks.
But why doesn't fresher coffee taste even better? Does the coffee remain stable between two weeks and two months after roasting? And is it undrinkable afterward?
We tested our recommendations on three coffees from our range—the Leica, the Dreispitz , and the Henrique . The coffees responded differently to aging. First, let me explain why coffee ages.
Why does coffee go stale?
Coffee ages because it's still alive . More precisely, because even dried green coffee still contains moisture (often between 9 and 12%). The embryo in the green coffee may be dormant, but it's still capable of germination. Green coffee, theoretically, has a long shelf life, but once it's roasted, the clock starts ticking.
We always talk about aging or the signs of aging , but never about spoiled coffee. The idea that coffee is undrinkable for health reasons would then be due to extreme storage conditions—high humidity, and ultimately mold growth, which is obviously not recommended. Hardly anyone would eat moldy bread either. But old coffee isn't a health hazard; it just doesn't meet our expectations of what coffee is.
Sensory and chemical analysis of coffee presents particular challenges because coffee is always a moving target (Beeman et al., 2011) . Coffee is inherently unstable; it changes rapidly, especially after roasting . Thus, sensory and chemical analyses are always complex, as the object being analyzed is constantly evolving—coffee is a living thing, even after roasting.
Various physical and chemical reactions during roasting change the composition of the coffee bean and are partly responsible for its aging . Roasting causes the bean to become more porous and lose volatile compounds (mostly aromas) more quickly. Maillard reactions during roasting create compounds that are susceptible to fatty acid oxidation.
We know this fatty acid oxidation as rancid coffee . Many of us have opened a pre-ground coffee pack that's been hiding somewhere in a cupboard. A rancid odor wafts out. Grinding massively accelerates the aging process , as grinding potentially increases the surface area of the coffee.
What factors cause coffee to age?
There are two main reasons why roasted coffee ages faster or slower: the packaging and the storage temperature .
The coffee packaging
Coffee packaging is becoming increasingly colorful, creative, and thus more eye-catching, but the primary purpose remains the same: keeping roasted coffee fresh. Coffee can generally be packaged in a paper bag if it is consumed very quickly. If the goal is accelerated aging, roasted coffee can be stored openly.
However, if roasted coffee is to be stored, it requires an oxygen barrier. This is usually polyethylene (PE) layers on paper or aluminum packaging. Aluminum has so far shown the best properties for keeping coffee fresh for a long time – however, it is aluminum that we have decided against for environmental reasons. We opted for PE-coated paper. While this doesn't keep the coffee fresh for as long as aluminum, since we don't sell it on supermarket shelves, the time from roasting to consumption is much shorter.
Supermarkets almost exclusively use aluminum bags, which are even filled with nitrogen. These coffees must not show any noticeable signs of aging for several months. The aluminum-nitrogen combination has so far performed best in this regard . While transparent coffee packages are visually appealing, they allow UV light to penetrate and accelerate the aging process.
The storage temperature
We know that higher temperatures accelerate chemical and physical reactions—and vice versa. Since roasted coffee is also a constantly evolving product, the external factor of high temperatures can cause the coffee to age faster.
High storage temperatures force aromatic compounds out of the packaging more quickly, as does the remaining CO2 produced during roasting, which keeps the coffee fresher in the package. While it smells good in the moment, it tastes less in the cup.
The opposite is also true—coffee doesn't need to be stored too cold. If coffee is stored in the refrigerator and then returned to room temperature for use, the resulting condensation leads to faster aging and, more importantly, uneven ground distribution.
Michel discussed this in a short video:
Yeretzian and Blank examine these factors in detail in their publicly available 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 roasted just a few days previously, the amount of CO2 is still very high. This results in a beautiful crema, a visual characteristic sought after by many coffee aficionados. We've detailed the crema myths here .
However, this high concentration of CO2 prevents a high extraction rate. In short: the CO2 in coffee behaves like a waterproofing spray for shoes. It keeps the water out, but under heavy use, the inside of the shoe also gets wet.
Coffee that still contains a lot of CO2 is surrounded by it. The water can extract less from the coffee during extraction because it "beads off" the CO2 . We still owe you a detailed study on this.
During extraction, the brewing water first dissolves acids from the roasted coffee. Backyard Coffee illustrated this beautifully in this video . Shorter extractions are always acidic because the contact time was very short. If we now consider our "impregnated" coffee, which has this CO2 coating, the following happens: the water penetrates the interior of the coffee grain less intensively, extracting the most easily soluble component: the acid.
Fresh coffee always has an intense, full crema, but tends to be acidic and has less texture , as these (sugar and fibers) can only be dissolved through longer extractions, or when the majority of the CO2 is no longer present.
What does old coffee taste like?
Of course, this depends on individual taste preferences, but rancid coffees are a thorn in the side for many. I was once invited to a sensory panel at Nespresso, where we tasted capsule coffees that were up to five years old. I was amazed at how sensitive the Nespresso staff was when it came to detecting the slightest signs of stale coffee, which I wouldn't have considered old yet. Nespresso sensory experts are extremely well trained to detect rancid coffee.
"Rancid," as mentioned above, is often a description for old coffee. We know it from oils that have gone stale. Describing rancid isn't easy —we often use loanwords like: stable, horse stable, dull, woody, pungent—what else can you think of? Feel free to share your descriptions in the comments.
In our experience, old coffee generally has the following characteristics:
- the aroma is masked by foreign notes (such as rancid, stable, woody, tallow)
- the flavors are no longer intense, and if so, not as originally perceived (fruity, floral)
- the texture may be less round
- the acidity works on its own, because the degenerating sweetness can no longer support
- the balance is no longer there, acidity and bitterness often dominate
- the aftertaste can be 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 in mind, we decided to examine three of our espressos more closely. We tasted the coffees every two weeks over a period of 12 weeks.
The setting of the experiment was as follows:
- Tasting after 2w, 4w, 6w, 8w, 10w, 12w
- Extraction: 19g coffee powder, 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 since developed a standard process. We try to produce a little more of Leica every year. This coffee is characterized by its fruity cherry flavor, plenty of sweetness, and a soft texture.
| Time after roasting | Comments |
| 2 weeks | Notes of lime, medium weight, tangy acidity, limited sweetness, limited balance |
| 4 weeks | very round, balanced, concentrated, syrupy sweetness, creamy |
| 6 weeks | Aroma limited, texture pleasantly soft and creamy, dense, dominant acidity, bitter aftertaste |
| 10 weeks | less intense flavors, engaging on the palate, good texture, pleasant, somewhat simple acidity |
| 12 weeks | Amarena cherries, no roasted notes, silky, thin texture, slight saltiness, bitter aftertaste, pleasant acidity, not further specified |
Leica tasting comments
The coffee after four weeks was our favorite . After three weeks, however, it's already at its peak , which lasts for a good ten days. If the coffee is very fresh, acidity dominates. A good three weeks after roasting, the balance is there, the fruity cherry notes are present, and the sweetness is noticeably more intense.
The aroma then fades more quickly after six weeks, before—interestingly—reappearing with great clarity after 12 weeks. However, the three-month-old coffee lacks the soft, dense texture that defines espresso for us.
Leica drinking recommendation: after 20 days at the peak
Dreispitz Espresso
Our signature blend for all espresso lovers . Balanced and uncomplicated, suitable for all common preparation methods. A full-bodied, chocolatey espresso, carried by a creamy body and delicate acidity.
| Time after roasting | Comments |
| 2 weeks | dark chocolate, lime acidity, pleasant Robusta note, very round, pleasant aftertaste, full body |
| 4 weeks | medium texture, slightly watery, subtle acidity well integrated (simple but clean), clean Robusta aftertaste |
| 6 weeks | intense Robusta notes, long Robusta aftertaste, powerful, well-integrated acidity, simple but clean; creamy-heavy Body |
| 10 weeks | Mild espresso with a stronger acidity. Somewhat disassembled into individual parts, rather light, Robust notes reintegrated, Balanced, becomes more intense as it cools down. |
| 12 weeks | Little aroma, light fragrance like Natural-Robusta, texture present, sweetness is missing, Robusta wineiness. Intensity and balance of attributes. Like a marathon runner who starts running and falls. |
Comments on the tasting of Dreispitz
The coffee after two weeks was our favorite. It keeps well for a week before the texture diminishes somewhat. Those who prefer a stronger Robusta flavor should be well served after six weeks. The taste changes in that the coffee from Nicaragua fades somewhat into the background, and the Robusta takes over. An interesting interplay that we also experienced intensely for the first time.
Dreispitz drinking recommendation:
1. Peak: after 12 days
2. Peak: after six weeks
Henrique Espresso
Henrique from Brazil is a chocolatey-nutty espresso with a full body and a long aftertaste. As an espresso, it's like a praline, with milk, it's like a dessert. Henrique packs a punch. And it's got a punch.
| Time after roasting | Comments |
| 2 weeks | very dark hazelnut, medium texture, roasted notes noticeable, low acidity |
| 4 weeks |
very harmonious, balanced, defined, mild acidity (delicate), very dark chocolate, almond notes |
| 6 weeks |
very dark chocolate, light acidity, more intense roasted notes, Age is making itself felt |
| 10 weeks | slightly disassembled, medium weight. Notes from licorice to classic dark chocolate, slightly roasted in the aftertaste |
| 12 weeks | no longer consistent. Faster extraction: 19g in 40 out in 24 seconds Loss of density, clarity, sweetness, A shorter extraction is good for the old coffees |
Comments on the tasting of Henrique
The Henrique is one of our darkest espressos, which is reflected in the flavor. The roasted notes are present, especially after two weeks. After three to four weeks, the coffee is at its peak—it is balanced, the roasted notes are gone, giving way to chocolate notes. After ten weeks, you can already sense the coffee's age; the balance is no longer as high as it was at the beginning.
Henrique drinking recommendation: after 20 days at the peak
What is the optimal age for roasted coffee?
We like it like this:
Filter coffee:
at least 7 days after roasting, 10 days is better, for naturals and other intensive fermentations wait 12 days
Espresso:
Wait at least 10 days after roasting, for light roasts about 14 days, for naturals about 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. This is our idea of how the coffees should taste. Anyone who chooses outside of this time frame isn't making a mistake; they're simply following their own preferences.
Our long-term test clearly showed that our coffees in non-aluminum packaging begin to show their first signs of aging after about 10 weeks, which is longer than the recommended two-month period. However, there are always surprises, such as the Dreispitz, which, after an initial high and a subsequent dip, recovered and reached its second peak after six weeks.
Can coffee be too old? Yes, if it no longer offers any sensory pleasure. However, old coffee doesn't have a negative impact on health. The rancid, stale, and tallowy notes can take over, while the lighter, especially floral, notes fade. But we're not talking about a defect here, but rather a normal aging process.
Unlike wine, coffee has a very narrow window of enjoyment. Wine, on the other hand, can improve with age. Coffee is like Snapchat, simply for taste. Wine is more like YouTube videos, which become more important with age.
