What is pre-soaking? How to presoak espresso in Italian style?

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Pre-immersion has only two purposes. Or, to be precise, all baristas eventually return to two purposes: to avoid the tunneling effect (pull a longer shot), and to extract the right extraction rate.

In the case of baristas, baristas can control very little as long as they are effectively powdered and pressed. The barista is just presenting the results of the system. Baristas can import raw materials stably enough to produce a stable product. But judging from many statistics, this is actually not the case.

To put it simply, the Italian coffee system is like a black box. The barista thought that as long as he kept putting in a, it would be A when he came out. But it's not. Because you don't know what this black box will twist an into. It could be A, it could be B, it could be Z. To put it simply, if the a you put into each time is fixed, you will think that I can produce An or a very similar product, but it is not.

Most baristas place great emphasis on a's production process (including techniques and tools), coupled with the fact that it is difficult to fully check the quality of the finished product (that is, you think it may be A, but the product is actually B, but you have no idea). A feature of the Italian coffee production process is that it is unlikely to have comprehensive quality control, so the stability of the black box itself will be more important. So when you have a way to measure my input a, then I have an 80% chance of getting a target result An or a very similar product, then this black box, even though you don't know how to do it, you should be able to agree that this black box system is good.

Black-box systems are often ignored because we want to know so much that we ignore the fact that we can find the consistency between input and output and then control the black-box output. However, paradoxically, these explanations often occur out of thin air and may not be in line with the actual situation.

Why do we have to mention the black box? Because effective prepreg is for you to get two things: proper prepreg and smaller tunneling effect. Unluckily, these two things are just like what the magic ball says: "Oh, no, every strength will create a weakness." Therefore, effective preleaching is not a combination of both, but a balanced and commercially applicable result of compromise between the two.

Pre-soaking, which I prefer to call pre-wetting, is the pre-stage of extraction (the stage at which the coffee juice is actually detached from pressed powder). So when shot drops out, it's in the extraction stage. So the "extraction time" is basically measured from the first drop to the last drop. No, the switch is turned on to the end of the switch.

The prepreg mechanism has many yuan, such as the common on/off, Slayer's flow-profile, Kees or some modified E61's Progressive infusion based on Hooke's law. Of course, in a broad sense, changing the current limiting valve is also a kind of prepreg technique (the smaller the current limiting valve is, the higher the prepreg effect is).

Effective pre-leaching is a good way to extract oyster. So if this prepreg can not improve the extraction rate, then the prepreg may not be "effective". To be precise, effective preleaching can make the grinding scale finer and create more total surface area, allowing you to produce a higher extraction rate at a "fixed extraction time". Intuitive observation is that when you maintain the extraction time, the rest of the method remains the same, a scale setting will often correspond to only one output and extraction time. Under the effective preleaching, keep the granularity setting and manipulation unchanged, you will find one thing: the extraction time becomes shorter (normally, if you measure the extraction rate, you will find it lower; because the extraction time is shorter). So then you will adjust the scale more finely. Omit the situation description in the middle, and in the end, you get a finer scale and more rhyme. This is the first thing effective extraction can do for you. Have you found that after the prepreg is opened, it seems that the result is basically the same, or is it not satisfactory? Of course there is, this is "non-effective" prepreg; it's right to be healthy.

Effective prepreg can also be used to control the tunneling effect. Especially machines with large WD values. A machine with a large WD value is almost useless in my mind, and it is a tunnel maker. But can it be slowed down by pre-soaking? Yes: if the prepreg is "effective". Some people have said that the tunnel effect can be used to create a special flavor, but I can't agree with this view, because the tunnel effect is a black box, and that is: he can't predict it. When you make a special flavor, but you can't expect his success, it's like throwing a dice with more than six sides, and you only have luck.

So the "effective" preleaching, which allows you to get a higher extraction rate and less tunneling effect at the same time, looks great. Less tunneling effect means higher sex. But not all beans want to improve the extraction rate. Shallow baked beans ok, deep baked beans what to do? If you buy a machine with a large WD value (I think it is higher than 90cc/10sec, even if it is high), you have to rely on pre-leaching to reduce the tunnel, but increasing the extraction rate may increase the risk of bitterness, then there is a dilemma. At this point, you have to look for tools in the black box system that can meet your needs in addition to pre-immersion.

Another dilemma of prepreg is that when you want to boil a cup of medium and shallow roasted coffee beans with enough sweetness, you have to increase the extraction rate, but the more exaggerated the prepreg behavior, the lower the extraction stability. Slayer increases the presoaking effect by sprinkling a small amount of water, but a small amount of spraying means that the water will fall more unevenly on the coffee pressed powder. This is "every strength will create a weakness."

Common prepreg, there is what I call the switch method, properly adjusted, will be a cheap but effective prepreg setting. The practice of the commercial Yangchun version of on/off= 1sec/ 1sec is almost ineffective pre-immersion. Effective prepreg is not difficult to see: many Italian machine versions can turn on their own set on/off time, such as on/off= 3sec/ 4sec, within the standard time. Almost as long as you stretch the off long enough and the amount of water in the on is just right, it can almost make the bean grinder much smaller (again, which means filling more and more later segments). However, if the amount of water in your on is insufficient, or the number of standing seconds is too long, it will affect the stability of the extraction. This is "every strength will create a weakness."

So "effective preleaching", ideally, should allow you to get the extraction rate you want and the good tunnel effect control you want. But in fact, it is impossible to achieve the maximum effectiveness of both. Because when you want to pull a higher extraction rate, the drift range of the extraction rate caused by uneven spraying will be larger, and when you prepreg is smaller, the tunnel effect will also cause too high extraction rate drift range. But it is absolutely possible to find a suitable but high-performing median through compromise; however, as an old saying goes, it is not possible to please both sides at the same time.

But back to the point: when you look at effective preleaching in terms of reducing the tunneling effect and increasing the extraction rate, you will find that a lot of preleaching is really poignant.