How long can coffee beans be kept after opening? Things to note when buying coffee beans

In essence, coffee is an agricultural product. Like many foods, its taste will gradually change over time. For coffee lovers, when to drink a bag of beans, most of them will add a "best taste" recommendation. So, how to judge the best taste of coffee?

Why does coffee have a shelf life?

Freshly roasted beans have a so-called "dry feeling", which is mainly manifested in a sharp sour taste, not mellow enough, not yet sweet enough, and a slight astringency lingering in the mouth. The roasting process is a complex chemical and physical reaction process, and there are variables that we do not understand. But the dry feeling is a real taste.

Each kilogram of coffee beans, in an unsaturated environment, will release about 6 to 10 liters of carbon dioxide, equivalent to 1% to 1.2% of the total weight of the beans. Thirty-five percent of this is released in the first three days after roasting. The carbon dioxide is then released along with an equal amount of aromatic volatiles (flavor ≠ aroma). Therefore, brewing coffee beans right after roasting will not have a good flavor.

After coffee is bagged, although it is isolated from the outside air, it will continue to react chemically with the air in the bag, for example:

The chlorogenic acid in coffee reacts with oxygen to produce a chemical reaction, releasing the aroma of the coffee beans. The coffee beans will continue to emit nitrogen dioxide (exhaust) for about 48 hours after they are roasted.

The aroma and taste of coffee itself will also change over time.

Most single-origin coffee beans begin to lose their aroma after one month in the bottle (for example, Butterfly has a floral aroma, Yirgacheffe has a fruity aroma), and the fruity aroma is one of the charms of single-origin coffee.

Fresh coffee can last two to three weeks

Freshly roasted coffee will maintain its peak flavor for about two to three weeks. Once roasted, the beans will need several days to release the gases (carbon dioxide) before they can be brewed and consumed.

About a week after roasting, the coffee flavor is at its peak, with the aroma and flavor characteristics of the brewed coffee being the strongest, and also showing the best mellowness and acidity of the coffee. But once it is left for a few more weeks, most coffees will no longer be fresh.

Storage temperature

The storage environment of coffee beans directly affects the length of time it takes to mature

The higher the ambient temperature, the faster the ripening and the shorter the ripening time. The lower the ambient temperature, the slower the ripening and the longer the ripening time.

Example:

• The coffee beans ripening period is different in summer and winter. Beans that can reach optimal maturity in 3 days in summer may take 5 days or even longer in winter.

• In the hot summer, beans mature quickly, but their flavor also decays quickly. Temperature can accelerate maturation and aging.

The best time to enjoy coffee

Counting from the time the coffee is roasted, it takes 15 to 30 days. Some coffees can be extended to about 45 days under proper storage conditions. Therefore, the "expiration" we mentioned is generally based on 30 days. At this time, the degassing of the coffee beans has basically disappeared, and the coffee beans of medium-dark roasting to dark roasting will slightly "exude oil". However, if the coffee is seriously oily due to improper storage, or smells only of wood, it means that the coffee beans are no longer suitable for tasting.

Beans that have passed their best-seller period = not fresh, not only do they lose their good flavor, but they also produce bad flavors. Although there is no specific statement about the current specialty coffee, it has generally been determined that the roasting of specialty coffee is between medium-light and medium-dark, and more than 80% of them are medium-light or medium roasted, and there is no Japanese roasting.

Because the heavier the roast (the longer the roasting time and the higher the temperature), the shorter the shelf life; medium-light or medium-roasted, which is what many people call the floral, fruity, nutty, chocolate, cream, etc. flavors, will lose their aroma over time.

"suggestion"

It is recommended to buy about 2 weeks' worth of coffee beans at a time. It is also recommended to use up the coffee beans stored indoors within 2 weeks as this is when the flavor is the best and most fragrant. Buy freshly roasted coffee and try to buy cooked beans and grind them yourself if possible. Don't stock up on any good coffee. Just buy enough for a month. It is best to buy drip coffee for only 15 days and buy more after you finish it!

Here are some things to keep in mind when buying coffee beans:

A. Origin

On the Internet, some stores may use coffee beans that are not from the place of origin, such as some Blue Mountain coffee, but its origin is not Jamaica. There are also cases where the bag only has Colombia or Brazil on it, but no specific estate information. These are usually coffee beans from major producing areas. Coffee from origin is also divided into commercial grade and boutique grade, so not all beans that say Ethiopia are boutique beans. It is best to be specific to the producing area. Beans that can be traced back to the origin are usually not too bad. If you are not very picky, you can try the flavors from different origins.

How to understand coffee names like "Ethiopia Sun-dried G1 Sidamohambella Oiran 2.0"?

Coffee beans have obvious regional characteristics. Before buying, you should understand the flavor of coffee beans. Coffee labels are like red wine labels. Generally, you can get a lot of information about the flavor of coffee from the labels. When we see the name of this coffee: Ethiopian Sun-dried Sida Mohambela Oiran 2.0, we can get the following information: Country: Ethiopia, Origin: Sida Mohambela, Grade: G1, Processing method: Sun-dried, and the name is Oiran 2.0.

If the beans you buy only have Ethiopia on them and no other information, they are usually from a major producing area.

B. Packaging date (baking date)

Pay attention to whether the packaging date is recent. Generally, the shelf life of green coffee beans is one to two years, and the shelf life of roasted beans is within two months. Therefore, you should choose freshly roasted coffee beans and use them up within the shelf life after purchase. Only in this way can you enjoy the most charming aroma and rich taste of coffee.

Freshly roasted coffee beans contain a lot of gas and have active respiration. During extraction, the gas in the beans is released, and what we see are beautiful and plump bubbles. However, for some lighter roasted beans, the bubbles are not so obvious.

C. Stores and brands

Needless to say, some coffee may be mixed with other types of coffee to reduce costs. So be careful. For example, mixing cheaper coffee beans with more expensive coffee beans, or mixing coffee beans of the same variety but poor quality with good quality coffee beans, will seriously affect the taste. So when buying coffee beans, try to choose a guaranteed store or brand. The popular home-roasted coffee beans in China are fresher than those bought in supermarkets. Choose a coffee shop you can trust.

However, many people say that they find the drink delicious when they try it on site, but the flavor is not good when they buy it home and cook it. This may be due to the following reasons:

• First, the particle homogeneity of home grinders and commercial grinders is different, in terms of uniformity and coarseness;

• In addition, the water quality used by some coffee shops may be relatively better than the tap water at home;

• For hand-brewed coffee, the material of the filter cup, the material of the hand-brew pot, etc. will have some impact.

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