Coffee roasting: the rhythm of roasting coffee beans

For professional baristas, please follow the coffee workshop (Wechat official account cafe_style)

Since the store promoted roasting at home and selling raw coffee beans, there has been a lot of talk about stir-fried bean technology these days.

It doesn't taste right. Orange turns into green beans!

"I bought a bag of coffee and raw beans that I drank here and went home to stir-fry themselves. why doesn't it taste like that? The scent of the flowers is gone! The taste of orange turns into green beans! "

In the past, when I bought a small packet of raw beans for baking in a foreign country, I usually chose my favorite flavor according to the cup test report listed on the web page. However, I found that "the taste is not right". I do not know what went wrong, and there is no way to complain about grievances.

While preheating the roaster on the shop floor for demonstration, I examined the bag of beans of different colors brought by the guests and said, "did you stir-fry at a low temperature for more than 15 minutes?"

He was surprised and said, "how do you know?" I saw that the color of the beans in the middle of first crack was still uneven, so I increased the fire later and deliberately prolonged the time. "

Fried coffee beans is a profound knowledge.

In a small fruit core, it contains raw materials that can be turned into more than 800 substances. It involves complex chemical reactions such as caramelization. For example, there are three basic substances A, B and C in beans. At a certain temperature and time, A plus C becomes D, while B plus D becomes F and becomes more and more. However, if the firepower is not properly controlled, the chain reaction will be interrupted, which will lead to dull taste; what is more, it will decompose the original substance and create a thankless smell. Therefore, the same kind of beans, fried well can highlight the potential, fried poorly, the taste will be bad.

Eye to nose to ear

"then how do we know where the chemical reaction goes?"

The term "bean appearance" is commonly used in Taiwan's industry, but in fact, it is quite appropriate. The appearance of beans includes not only the surface color, but also the size and fullness of the beans, and even the degree to which the central crease turns outward can indirectly reflect the traces of heat on the beans. Just like steak, quick frying and slow frying over high heat have the same surface color, but the center has different degrees of maturity and tastes different.

To accurately judge the stage of fried beans, there are several methods such as listening to sound, timing and temperature detection. At the beginning, the author will also synthesize the above-mentioned methods which have both indicators and quantification. But with more experience, you will find that what happens in the furnace cannot be described by a single "roast profile curve". Moreover, the various indicators can only be "post-competition review". Improper curve, a batch of beans has been reimbursed! The only way to have foresight and react immediately is to use a sense of smell that is extremely difficult to master.

"when it comes to the explosion stage, beans are generally swollen and full. The uneven color is probably due to the lack of thermal impulse, the chain reaction has been broken, and it is futile to add fire. The taste produced can no longer reflect what is contained in beans. " I looked at a packet of reimbursed coffee beans and said.

Patrick Tam (owner of the boutique coffee shop Knockbox, approved barista of the American Fine Coffee Association and European Fine Coffee Association, CQI recognized cup tester, Cup of Excellence's first Hong Kong judge)

MING PAO ARTICLE