Discuss coffee bean oil and coffee bean freshness

Oiled coffee beans and freshness

What is the relationship between the "oil" of coffee beans and the freshness? Should we buy coffee beans that have "oil" or "no oil" in appearance?

Have you ever seen oily coffee beans? Why do some coffee beans have a shiny surface, while others are "dry and comfortable" without greasy? What is the relationship between the "oil" of coffee beans and the freshness? Should we buy coffee beans that are "oily" or "unoiled" in appearance?

Coffee oil that is not oil.

These "oils" distributed evenly on the surface of coffee beans are actually not "oils", but water-soluble organic substances that look like oils. "Coffee oil" itself contains many aroma ingredients of coffee, which can be dissolved in water, so the surface of your brewed coffee will not be covered with greasy oil.

There are two reasons for "oily beans".

There are two reasons for "oily beans". A) stale shallow baked beans b) fresh deep baked beans. The following in-depth discussion.

A) stale shallow baked beans

The shallow roasted beans, which are light brown in appearance, are dry and will not produce oil after baking. About six days after baking, the phenomenon of "dotted oil" begins to appear (dotted oil droplets appear on one side of the coffee bean). Slight "dotted oil" does not mean that it is not fresh, but sometimes the flavor of shallow roasted coffee beans is at its peak. Continue to put, more than two weeks after the baking, the surface of shallow baked beans gradually covered with a bright glow, at this time, "shallow baked beans" flavor has begun to decline, should avoid buying.

B) fresh deep baked beans

Deep-baked beans with dark brown appearance show a slight glossy appearance after baking, and a large amount of oil begins to appear on the surface from the second day to the fifth day after baking. The bright-looking "deep-baked beans" not only do not mean that they are not fresh, on the contrary, the deep-baked beans will gradually dry out three weeks after they come out of the oven, and finally become dry-flavored beans. Therefore, if you see coffee beans that are dry but dark brown in appearance, please pay special attention to whether they are marked with the date of baking, which is most likely to be spoiled beans.

The method of judging the freshness of coffee beans

Even if it is not fresh, the appearance of the "shallow baked beans" will gradually dry out after a long time (such as three months), and finally return to the dry and unoily appearance. Thus it can be seen that the appearance of oil is only a reference to judge the freshness of coffee beans, not absolutely.

How should we judge the freshness of coffee beans?

First of all, you should clearly mark the baking date for the product (you should buy products with a baking date of less than one week, and do not trust the shelf life marked on the coffee bag) from coffee roasters who have a brand reputation and emphasize fresh roasting. avoid buying coffee beans with unmarked baking date and unknown freshness. In addition, excellent coffee bags are usually designed with a "one-way exhaust valve" (a button-shaped hole in the top of the coffee bag) for coffee beans to discharge naturally occurring carbon dioxide. Point the one-way exhaust valve at the nose, gently squeeze the coffee bag and smell the gas. If it is a charming and fragrant coffee aroma, the freshness will not be a problem. On the contrary, if it does not smell strong enough, or even smells of smelly oil, it means that this bag of coffee has already gone bad and should be avoided.

-conclusion-

"the appearance of freshly baked shallow baked beans should be dry and oil-free, and the surface of freshly baked deep baked beans should be shiny" is the correct concept that we should understand. When buying coffee beans, the appearance of oil, no oil is a reference index to judge the freshness, but not absolutely. It is the best way to buy freshly roasted coffee beans with a good reputation and a baking date.