Is there really a perfect way to brew coffee?

There is no perfect way to brew coffee

According to Mr. Danbe, the Royal Society of Chemistry (composed of people dedicated to the chemical science) published the book "Perfect Black Tea Brewing Method" in 2003.

"The book 'scientifically' describes the conditions for brewing black tea, such as temperature, time, and water composition. If you can faithfully reproduce them, you can brew delicious black tea. The book fully reflects the British persistence, scientific inquiry, and playfulness, and is a useful source of information for black tea lovers." (Danbu)

There are so many guides like this in Japan, not just for black tea, but also Japanese tea, Chinese tea, and of course coffee brewing methods. These guidebooks are everywhere, and you may even be confused about which one to choose. However, I dare to assert that there is no so-called "perfect brewing method" for coffee, and Mr. Tanbe agrees with me :

“It is much more difficult to brew delicious coffee than black tea. The word perfect cannot be used. The reason is that coffee contains much more ‘impurities’ that cause off-flavors than black tea. Therefore, it requires superb extraction technology to remove those impurities.”

So, that’s why there is no such thing as an absolutely perfect brewing method in the world of coffee. I totally agree.

If I say that the extraction of black tea is much easier than coffee, black tea fans may be very angry. This is because the ingredients that cause the off-flavor of black tea are originally few, and if you want to brew black tea to taste good, basically you only need to know how to brew the aroma components "strong/light".

But coffee is different. When brewing coffee, you need to "extract the delicious ingredients just right while not extracting the unpalatable ingredients ". This is a contradictory task that requires you to do at the same time. Therefore, it is much more difficult than black tea.

●The era when extraction experts are favored

40 years ago, when I started working in the coffee industry, extraction technology was more important than roasting technology. As long as the extraction technology was good, no matter how bad the quality of the green beans was or how rough the roasting technology was, there was always a way (no, absolutely a way) to brew delicious coffee. This "extraction myth" shrouded the coffee industry. This is like "telekinesis" that believes in the divine wind. Looking back now, I can't help but feel a lot of emotion. What is the reason for this craze of "extraction supremacy"?

Professional coffee magazines have been reporting on extraction in great detail, with all the famous coffee extraction experts on their covers. It is a pity that I cannot introduce all those theories here. The unique extraction techniques that the Japanese have been concentrating on thinking deeply about were presented like an "exhibition" at the time.

However, now people believe that "delicious coffee is 80% green beans and 2% roasted." Although I don't know the basis of this ratio, it seems a bit sad to say that "extraction technology" and "extraction celebrities" have been thrown behind the public and almost forgotten.

When specialty coffee first appeared, the slogan "From Seed to Cup" was promoted by people like a slogan. It is no longer just the patent of specialty coffee. No matter what grade of coffee, if the final product in the cup is rough coffee, no matter how high-sounding the theory is, it is meaningless. Everything is good if the result is good. There must be no slackness before the best liquid is poured into the cup.

Whether it is roasting, grinding or extraction, I will set priorities in each process. This is because all the links are organically linked. If any link is lacking or sloppy, all the efforts will be ruined.

●Four conditions for brewing “good coffee”

In the previous work "Specialty Coffee Encyclopedia", it was mentioned that brewing "delicious coffee" requires several conditions. Before explaining this, please recall the previous description of "good coffee" and "bad coffee". To brew "good coffee", the following 4 conditions must be met.

①High-quality green beans without defects;

② Freshly roasted coffee;

③Freshly ground coffee;

④Freshly brewed coffee.

If we summarize the above four points, it is " the coffee produced by roasting flawless high-quality raw beans properly, grinding and extracting the roasted beans properly while they are fresh ", which is what I call "good coffee". I try to avoid using the words "delicious" or "unpalatable" to express it. This is because I think "delicious" or "unpalatable" is a matter of individual preference after all, and cannot be expressed as an objective discussion.

I hope everyone can understand clearly that when I use the word “delicious”, I mean the “delicious” when providing “good coffee”. I do not mean the “delicious” that bypasses the above four conditions and simply remains in the scope of personal preference.

The taste of coffee is always unstable and volatile. Since it is an agricultural crop, there are both good and bad harvests, and there are deviations that occur during the refining stage. In addition, roasting is not always stable, and grinding and extraction are not fixed in one place. Some people will use this subtle deviation as an excuse to say "because it is an agricultural crop, there is nothing we can do about the taste changes", and use this to defend customers' complaints, but I think if you consider yourself a professional coffee person, you must correct this subtle deviation and make a fixed taste under any conditions. Professionals must be able to provide "taste reproducibility" of the same taste, and it is by no means a one-time deal.

● If the water temperature rises, the bitterness will also increase

If we follow the practice of our own store to arrange the process of "from seed to cup", it would be:

①The aroma characteristics of raw beans;

② Hand selection of green beans (first time);

③ Baking;

④ Hand selection of roasted beans (first time);

⑤ Storage and management of roasted beans;

⑥Blending of coffee beans (mixed);

7. Grinding;

⑧Extraction.

What does the order of ① to ⑧ mean? As I said before, all the processes before pouring into the cup are closely related and no link can be missing.

Because we are not gods, we cannot be perfect. There will be mistakes somewhere. For example, if you are careless when hand-selecting, there will be a lot of unripe beans and fermented beans mixed in with the raw beans. If you don't stop the roasting at the scheduled time, it will lead to over-roasting. If you make a mistake in the grinding scale, it will be too fine and clog the drip filter, etc.

There is a little principle here.

[First] " Errors in the previous process can only be corrected in the next process ." For example, the process should have stopped at Full City Roast but was delayed to the next stage, French Roast. Although it was only a few tens of seconds of over-roasting, the difference in taste was very obvious. Because over-roasting makes the bitterness stronger. Can we find a way to correct it?

The only way to remedy this is to grind the French roasted coffee beans a little coarser in stage 7. There is a rule for the mesh of the filter powder, which is " the finer the grind, the stronger the bitterness, the coarser the grind, the less bitterness, and the taste becomes lighter ." The finer the French roasted coffee beans are ground, the more bitter the taste will become.

Then in the eighth stage, the water temperature should be slightly lowered and the extraction volume should be slightly increased. The rules for these practices are " the higher the water temperature, the more bitter (= the less sour), the lower the water temperature, the less bitter (= the more sour) " and " the more the extraction volume, the less bitter (= the more sour), the less the extraction volume, the more bitter (= the less sour) ."

In summary, it means "grind French roasted coffee beans a little coarser and use a slightly lower water temperature to fully extract them." The intention of doing so is to make the aroma of the coffee closer to the target dark city roasted aroma, but this is always an emergency measure for emergency disposal and cannot brew the target flavor 100%. Thus, a principle of approximate justification is generated.

[Second] " If you just make corrections in the next process, it cannot offset the errors in the previous process ."

Once a "deviation" occurs in a certain process, no matter how it is corrected in the next process, it will be ineffective. If the coffee beans roasted are for one person, it is not a big deal. If the beans roasted incorrectly are in units of 10 kg, then you need to make corrections in ⑦ or ⑧ tirelessly until all the roasted beans are processed. In short, the lesson it teaches us is that no matter which process, we must be calm and not underestimate it.

● Freshly roasted coffee is not delicious

Let's go back to the beginning. Before the "extraction" process is the "grinding" process. We have touched upon the key points. However, I still hope that everyone can review it again and pay attention to the ②~④ items of the 4 conditions for making "good coffee" mentioned earlier.

When making buckwheat noodles, "freshly ground, freshly rolled, and freshly cooked" are the conditions for delicious buckwheat noodles. The same is true for rice, which is most fragrant when it is just milled. This is because both buckwheat noodles and rice begin to oxidize and lose their flavor the moment they are ground or the husks and bran are removed.

The same is true for coffee. "Freshly roasted, freshly ground, and freshly brewed" is the trick to making delicious coffee. However, to be precise, the "freshly roasted" coffee just taken out of the inner pot is not delicious. Whether it is hand-roasted or other methods, if you have roasted it yourself, you should know that freshly roasted coffee beans have no taste even if they are "freshly ground and freshly brewed".

This is because the flavor is not extracted. Indeed, if the aroma is good, it is worth drinking, but we cannot taste the flavor. I often use the expression "the coffee beans exploded". In fact, if you use drip extraction to extract freshly roasted beans, the coffee powder will "explode", either the surface of the powder will crack or it will spray like a volcano, and it is difficult to form a permeable layer .

Mr. Danbe, who roasts his own coffee, feels the same way. He says, "The proper way to describe it is 'lack of stability'. The taste seems bland. The reason is carbon dioxide. Freshly roasted green beans produce a lot of carbon dioxide . Therefore, the taste tends to be sour, and since the carbon dioxide content is not constant, the taste is hard to predict. From my experience, coffee made from coffee beans that are 2 to 3 days old after roasting is the freshest and has the most stable and balanced coffee ."

●Key points for grinding roasted beans

After roasting, coffee will release its aroma, but its ingredients will gradually deteriorate due to oxidation. After being ground into powder, the overall surface area will increase by dozens of times, and the contact area with air will increase significantly, and the speed of deterioration is incomparable to that of raw beans. Therefore, it is best to grind it just before brewing .

If the production of carbon dioxide is relatively stable and the roasted beans are in a stable state, the next question is what kind of grinder to use and how to grind. A famous coffee master once said that if the coffee beans are roasted correctly, whether it is ground with a small hammer or a mortar, any form of grinding can make delicious coffee. This statement is only half right. After high-quality coffee beans are roasted correctly, no matter how they are ground or what tools are used to extract them, they will generally be delicious.

However, this book is not a hobby book. It is a book that professionals can also use as a reference. Therefore, even if you use a hammer to grind, the various experimental conditions must be clearly stated in detail, such as how much force is used, how much time is spent, to what extent the grinding is done, and what kind of hammer is made of. In this way, our conclusion is that the grinder with better performance than hammers and pestles is the most suitable.

Although it is still a review of the old work, the key points of grinding with a grinder are summarized as follows:

① The grinding degree (particle size) should be uniform;

②Avoid frictional heat during grinding;

③Avoid producing fine powder during grinding;

④Choose a grinding degree suitable for the extraction method.

In ①, the word "uniform" in grinding appears. Whether it is roasting, grinding or extraction, there must be no "unevenness". Unevenness will cause "uneven" taste. No matter which step of the process, I always keep in mind the pursuit of uniformity. Minimize the unevenness. This is to get a cup of coffee without impurities, uniform quality and balanced taste in the end.

The second point is the problem of "frictional heat generated when grinding beans". If the heat generated is excessive, it will accelerate the oxidation of coffee ingredients and lead to deterioration of taste. Frictional heat generated when grinding buckwheat and other grains is also a common problem. The difference between coffee and buckwheat and wheat is that coffee beans become "hard and brittle" after roasting. Therefore, coffee beans can be ground more easily and less heat is generated. However, frictional heat problems will also occur when using commercial grinders for continuous grinding. Coffee and buckwheat have this in common: try to use equipment that can avoid frictional heat.

The third point is that the problem of fine powder is more troublesome than friction heat. If a large amount of fine powder is mixed, it will cause over-grinding and dissolve unpleasant astringent and other miscellaneous flavors. To avoid the production of fine powder, the most important thing is to choose a grinder that does not produce fine powder. Or use a tea strainer to dust off the fine powder and silver skin together. It is also very important to clean the grinder carefully and brush off the fine powder with a brush.

The fourth point is the grinding degree suitable for the extraction method, which is a matter of course. If the deep roasted ultra-fine ground powder used to make espresso is extracted by the filter paper drip method, the holes of the filter paper may be clogged, causing the so-called "retention" phenomenon, making it difficult for water to pass through, prolonging the extraction time, and ultimately leading to over-extraction.

Each extraction device has a grinding method for coffee powder that is suitable for the device. Diagram 24 shows the matching of the coffee powder filter and the extraction method.

I am Afei, and I have been engaged in promoting coffee culture for nearly 5 years. I have been to coffee farms in Yunnan, Taiwan, Indonesia, and coffee-consuming cities in Italy, Germany, etc. I love specialty coffee and want to make friends who love coffee as much as I do. Welcome everyone to follow my Toutiao account, and share and exchange knowledge about specialty coffee, latte art, and opening a shop.