How to judge the freshness of a cup of coffee? What is the function of the exhaust valve on the coffee bean bag?

How to judge the freshness of a cup of coffee?

The most direct way is to know the freshness from the baking date, but when you buy coffee beans that are not marked with a baking date, you can judge them in the following ways.

Aroma: fresh coffee beans after grinding will have a strong aroma of coffee, usually can smell obvious aroma of flowers and fruits, the taste is more full-bodied and layered, while not fresh coffee beans, the aroma is not obvious, the taste is more simple and rigid.

Expansion: fresh coffee beans contain unreleased gas. Injecting hot water on the coffee powder during stewing will quickly release gas, gushing foam on the surface and causing the noodles to expand. Usually, the greater the expansion, the fresher the beans.

Oil out: the glossy surface is also a way to judge. In addition to the degree of deep baking that brightens the oil of the whole coffee bean, it usually represents that it has been roasted for a long time, but the coffee beans with lighter roasting generally do not produce obvious oil. therefore, this method is more suitable for medium-to deep-roasted beans.

Coffee beans are raised because about 2% of the weight of freshly roasted coffee beans is carbon dioxide, and this large amount of carbon dioxide emits carbon dioxide along with the storage environment, equipment, or method. the pressure in the package is higher than an atmospheric pressure, and the pressure helps to integrate the aromatic substances with the oil, making all the aromatic substances inside the coffee beans easy to extract.

What is the function of the exhaust valve on the bean bag?

When you see the exhaust valve of a coffee bean bag, don't think it's a "smell hole"! After squeezing the inflated bean bag, the space vacated in the bean bag will speed up the oxidation of coffee beans and shorten the taste period. Don't squeeze the bean bag to smell it.

The exhaust valve has the function of moisture-proof and fresh-keeping, so that the carbon dioxide in the bean bag can be discharged unidirectionally, and the external air will not enter the bean bag and affect the flavor, which is an excellent way to preserve the bean during cultivation.

Japanese one-way exhaust valve

The back of the "Japanese one-way exhaust valve" uses a filter screen, and the upper cover covers the film. When the gas pressure in the bag is greater than the external pressure, it can quickly discharge excess gas and carbon dioxide, effectively block external air reflux, and isolate moisture and dirt. The effect is better than the common Taiwanese valves on the market.