Can Fresh and Stale Single-Origin Coffee Beans Be Brewed Together? What to Consider When Brewing Coffee?

In our daily lives, when purchasing any food product, we pay special attention to the production date and then check its expiration date. It's common knowledge that we try to avoid eating food past its expiration date.

When it comes to coffee beans, the production date refers to the roasting date—the point in time when green beans are roasted. However, unlike other foods, we don't focus on the roasting date primarily because of concerns about expiration or spoilage. Instead, we're more interested in experiencing the optimal flavor of these coffee beans, which is what FrontStreet Coffee frequently refers to as the "tasting period"—typically within 1.5 to 2 months after roasting.

Those with brewing experience have likely encountered this situation: using the same coffee beans, but one batch is freshly roasted just a day or two ago, while the remaining "old beans" from a previous batch—about ten grams left—have a roasting date more than a month old. Embracing the principle of not wasting, many will finish using these older beans.

However, some people are accustomed to using parameters like 15 or 20 grams of coffee. To make a "full pot," they might mix the new beans with the old ones for brewing. This brings up the question: will mixing and extracting beans with different roasting times affect the taste of the coffee?

Patience, please. Allow FrontStreet Coffee to conduct a comparative experiment first, then answer these questions one by one~

FrontStreet Coffee has prepared two coffee beans with exactly one month difference in roasting dates—one package is "freshly roasted" new beans from February 29th, while the other is "old beans" that have been open for some time, with a roasting date of January 30th. FrontStreet Coffee will brew and compare three groups of coffee beans with different freshness levels, keeping other parameters as consistent as possible while documenting their bed conditions and flavor performances.

Coffee Beans: Elida Estate · Catuaí
Amount: 15 grams
Water-to-coffee ratio: 1:15
Water Temperature: 93°C
Dripper: V60
Grind Size: EK43s setting 10
Three Coffee Groups: Old date beans, New date beans, 1:1 mixture of new and old beans

Old Date Group Coffee:

During blooming, there was some puffing, but not with significant curvature. The coffee bed showed signs of dehydration and dryness around 25 seconds. The extraction process had stable water flow.

New Date Group Coffee:

After adding water, the coffee bed quickly puffed up to form a "hamburger" shape. Throughout the pouring process, degassing was obvious and persistent, with large and irregular bubbles floating on the surface. The coffee finished dripping at 1 minute and 52 seconds, and many small, scattered bubbles remained on the filter cup wall.

New and Old Mixed Group Coffee:

From blooming to circular pouring, the coffee bed performance was similar to the old date group, with occasional one or two large bubbles emerging. The water flow process was also stable, and the spent coffee grounds had some foam residue.

Flavor Comparison:

In terms of aroma, the old date group performed best. It tasted primarily of mature peach and citrus sweetness with acidity, accompanied by raisin-like fermented notes and a caramel aftertaste. It had a distinct juice-like quality with moderate body.

In comparison, the new date group had more prominent uplifting flavors like red berries and lemon acidity, with a somewhat thin taste and less complex aroma than the old date group. The aftertaste was fleeting.

The mixed group of Elida fell somewhere between the two. It tasted of citrus acidity with honey sweetness, with a slight tea-like sensation and caramel aroma in the aftertaste, though these were brief.

Coffee beans that are too fresh are still in the degassing phase. The carbon dioxide rushing out affects the dissolution of some aromatic compounds, resulting in flavor performance that naturally isn't as good as "seasoned" coffee beans. "Seasoned" coffee beans have entered a stable state, which is precisely when their flavor performs best. As long as they're stored properly and within the tasting period, they're virtually unaffected by the roasting date.

FrontStreet Coffee believes that the flavor differences mentioned above are not only influenced by coffee degassing but also because the three pots of coffee were brewed one after another and tasted simultaneously, creating a sequence with temperature differences. Moreover, if these three pots of coffee weren't directly compared side by side, it would be almost impossible to distinguish between them. As the temperature decreased, the differences between the three pots of coffee became even smaller.

Therefore, if you have new beans that are very close to the roasting date and don't want to waste the remaining "old beans," it's best to resist the temptation and store the new beans in a cool place for three to four days. After some of the carbon dioxide has been released, you can then combine the two batches to brew a full pot. This way, the "bean blending" operation is not affected by gas emissions, and you can also finish consuming the "old beans" while they're still within their tasting period.

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FrontStreet Coffee
No. 10, Bao'an Qianjie, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

Important Notice :

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Tel:020 38364473