Daily brewing | judge the extraction of coffee by looking at the shape of powder dregs and powder beds

Professional coffee knowledge exchange More coffee bean information Please pay attention to coffee workshop (Weixin Official Accounts cafe_style)

Hand flushing, including the understanding of a bean barista, the mood of the guests experience.

Hand washed powder layer is related to many factors, such as:

Degree of roasting: deep-baked beans are light, mature, and the flour does not completely sink to the bottom when brewed.

Shallow-baked beans are heavier, less exhaust, and easier to pile up.

Powder amount: the smaller the powder amount, the easier it is to destroy the powder layer and cause flow.

Degree of grinding: coarse grinding is easier to form a flat surface than fine grinding

Water injection method: focus on the center of water injection, the more likely it is to have a pit shape

The book or teacher has said that the factors affecting extraction are probably: how much powder, grinding thickness, water temperature, water flow size. Fine grinding, high water temperature and low water flow can increase the extraction rate and make the coffee stronger. Generally beginners just get started in order to be afraid of the lack of flavor extracted, but also in this way to extract a variety of coffee.

But as more and more items are brewed, different roasters and different degrees of roasting, you will find out why some coffees are not so perfect. Why do some shops grind coffee with coarse, low temperature and high water flow? It used to be said that the higher the temperature, the more bitter, and the lower the temperature, the more sour. But some light roast coffee will only be the higher the temperature acid ah!

In fact, this is related to the solubility and saturation of coffee ingredients. Certain components in coffee dissolve faster as the temperature increases. Since some ingredients dissolve faster, others dissolve slower.

Conversely, at low temperatures, components that dissolve quickly at high temperatures slow down and acidic substances dissolve quickly.

So... What ingredients dissolve quickly at high temperatures? Which ingredients are dissolved in the second half? In fact, the conditions of each coffee bean are different, you can do an experiment to see: the extraction of a cup of coffee is divided into the first half and the second half, that is, divided into two cups.

Take light roasted coffee beans (take butterfly flower as an example, please refer to Panama butterfly flower for detailed parameters)| Coffee workshop study classroom), the first half of the majority of sour aroma components, the latter half of the majority of sweet and fatty components. That is, the dissolution rate of sour ingredients is relatively fast, and the dissolution rate of sweet and fat is relatively slow.

Returning to the conditions affecting extraction mentioned at the beginning, more powder, fine grinding, high water temperature and fine water flow are all to enhance the extraction of the first half flavor. What about the second half? Of course, the proportion will be very small, and sometimes there will be a feeling of empty in the second half of the drink, and the balance of the whole cup of coffee will disappear.

Why is light roast coffee so sour? Some people say it's because the light roast retains the acidity and more ingredients so it's so sour. Shouldn't it be sweet and sour? So... Sweet and fat? Because the powder is more finely ground, the water temperature is high and the water flow is slow ~ Try to reduce the extraction concentration in the first half, and you will get the flavor in the second half. But if you drop too low, you get a glass of sweet water.

The degree of roasting and the length of roasting will affect the weight loss ratio of coffee. The water content in raw beans is about 11%, and the water content after baking is about 2%. Therefore, the weight loss ratio of water is about 9%, the weight loss ratio of raw beans and cooked beans is about 13%-17%, and the proportion of water is deducted, so the weight loss of other components of coffee beans is about 4%-8%. That's a 4% difference in composition... Simply put, it is coffee extraction, some deep roasted beans need to use 1:13 extraction ratio to taste good, some light roasted beans need to use 1:18 or even 1:20 extraction ratio to balance. Daily brewing| Powder water ratio doubt, gold cup extraction in the end is calculated powder water ratio or powder liquid ratio?

Roughly speaking, the soluble matter of coffee is about 30%. 20% of them are the good ingredients we want to extract, and the other 10% are the bad ingredients in the later stage (so explain why some baristas cut the tail). But there are always exceptions to everything, if there are coffee beans even after 10% of the flavor is also good, whether it should also be extracted to be a cup of coffee with complete flavor?

Try breaking open the coffee bed after brewing a cup of so-called premium coffee to see if the coffee grounds still have aroma. If there is, it means that your coffee still has some aroma substances that have not been extracted, so the powder residue still has aroma.

Finally, we extract a cup of coffee and look at the state of the powder bed.

I personally prefer all the flour to participate in the extraction of light and medium baked beans (uniform extraction = same time immersion), so the ideal state for uniform extraction is horizontal and wall-free.

For medium baking medium deep I will choose powder hanging wall that looks like a small pit or a slight bed in the middle of the shape, at first with stable and supple fine water flow does not destroy the powder layer, reduce convection, full extraction. The second half is uniform water injection, and the process will also lose temperature seriously due to long time or segmentation. In order to prevent excessive extraction in the middle, the water temperature will be deliberately lowered far from the target value, playing a dilution role. It'll come out nice and mellow.

Finally, I feel that in paying too much attention to the so-called "powder wall shape" problem, we cannot ignore the taste of the real experience. A good cup of coffee is all the key to extraction.