How to judge whether the coffee beans are fresh _ will the fresh coffee beans produce oil _ how to preserve the fresh coffee beans

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Recently, as a result of taking part in some coffee activities, I bought several kinds of beans and piled them at home, resulting in a little more hoarding at home. It is rare to hide at home today, so I decided to wipe out some of the inventory. So I took out a bag of coffee beans that had been opened a month ago, only to find it. There's oil coming out.

Some people will say, "the fresh coffee beans I bought are oily?" Are you sure you can't drink beans that are difficult to pour out oil? What kind of 'grease' do you usually need when you extract espresso? If I buy coffee beans, how can I know if they are fresh? If I want to extend the life of fresh coffee beans, how can I keep them? "

It seems that there are a lot of knowledge points to be said today. Let's do it one by one.

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What is the reason why ● makes beans "out of oil"?

There are two kinds of beans that produce oil, one is fresh deep-baked beans, and the other is stale shallow baked beans.

Deep-baked beans, deep baking heat, after baking appearance shows a slight glossy, the first day to the second day, began to appear a large number of "glossy". Three weeks after the appearance of the oily "deep-baked beans", the surface of the "deep-baked beans" began to dry slowly, and finally turned into dry stale beans. At this time, the deep-baked beans ended its brilliant raw beans.

Shallow baked beans, shallow baking heat, dry appearance after baking, about five days out of the oven began to appear "spot oil". Note that this does not necessarily mean that it is not fresh, but may be the peak of its bean production. After two weeks, the surface of the shallow baked beans began to shine evenly, and it smelled like oil. It is suggested that the coffee beans should not be drunk any more, but should be ground into powder and exfoliated when taking a bath.

What is the "grease" of ●?

Espresso extract the upper golden yellow to chocolate-colored liquid, called Crema, is the soluble substance extracted by high-temperature and high-pressure water, emulsifies the fat and oil that naturally exists in the coffee, and mixes the air to form some tiny and fine bubbles.

Because fresh roasted coffee releases a certain amount of carbon dioxide, and carbon dioxide is also involved in the emulsification process, the fresher the coffee, the more carbon dioxide is released, and large bubbles can be seen during extraction.

Factors that affect the oil include the roasting degree of coffee beans (light and light color), freshness, the treatment of raw beans (usually sun or honey-treated beans are richer than water-washed beans), origin and extraction equipment.

How to choose coffee beans by ●

"looking, hearing, asking and cutting" is the method used in traditional Chinese medicine to see a doctor. Buying coffee beans is somewhat similar to this.

When buying coffee beans, pay attention to observe the appearance of coffee beans, defective beans are relatively less, whether the color of single bean is the same, whether the size and shape of particles are similar, (the size and color of beans are different is a normal phenomenon) whether the shallow baked beans produce oil, grab one or two and put them in the mouth to taste, the crisp taste shows that the coffee beans are not damp, and the lips and teeth stay fragrant that the coffee beans are fresh.

If the coffee beans lose their fragrance, or even appear stale or "halal flavor", it means that they are no longer fresh.

But there is a kind of coffee beans that you must stop drinking, that is, coffee beans that turn yellow in appearance. Coffee beans are moldy inside and breed with bacteria, and their appearance changes chemically to turn into a yellow shell.

How does ● preserve coffee beans?

Someone asked, "can coffee beans be refrigerated?"

Please look at my frightened eyes!

The sharp temperature difference inside and outside the refrigerator will make the water in the coffee storage bag condense, and the coffee beans will soon get damp.

"what about freezing?"

This is really a good question!

In 2016, a team of researchers from the University of Bath in the UK, working with a local coffee shop, found that freezing coffee before grinding can make the coffee powder more uniform and the particles arranged more tightly, thus making the coffee taste fuller and the coffee will become more delicious.

The team found that the lower the outside temperature, the tighter and neater the arrangement of coffee powder particles. The uniformity of coffee grinding is very important for coffee extraction. The more uniform the grinding, the more sufficient the coffee extraction.

It is reported that the research report has been published in Scientific Reports, and it has also been featured in Nature magazine.

Wow, you know, as a female doctor of pharmacology, seeing this is really jealous, Scientific Reports in 2016 impact factor 5.228, become the target of Chinese people, known as doing scientific research, is bound to have an article.

Coffee beans try to avoid light from storage, because direct light does great harm to coffee beans, and non-direct light can also accelerate the decline of coffee flavor. So coffee beans should be kept away from light and sealed at dry room temperature as far as possible.

● fresh coffee bean brand recommendation

Qianjie coffee freshly roasted single product-Italian fresh coffee beans: Yega Sheffield Coffee, Brazilian Coffee, Manning Coffee and so on are fully guaranteed in brand and quality, suitable for brewing with all kinds of utensils. And more importantly, the performance-to-price ratio is extremely high, a pack of half a pound 227 grams, the price is only 80-90 yuan. According to the calculation of 15 grams of powder per cup of hand-brewed coffee, 15 cups of coffee can be made in a bag, and each cup of coffee costs only about 6 yuan, which is very cost-effective for the normal price of 30 or 40 yuan a cup in a cafe.

Qianjie coffee: Guangzhou bakery, the store is small but a variety of beans, you can find a variety of unknown beans, but also provide online store services. Https://shop104210103.taobao.com