Pre-infusion is something I see many people use when making their filters or espressos, but is this technique really being used well? What is the purpose of using a pre-infusion? When should it be done and when should it not?...
What is preinfusion?
Pre-infusion is simply the act of moistening the coffee bed so that it prepares for extraction. A simple definition, right? Well, let's dig a little deeper into this.
When water comes into contact with the coffee, it causes a release of gases (CO2) which tend to come to the surface. On the other hand, we have water that tries to affect all parts of the coffee bed, but has the problem of encounter the opposite force of degassing, for this reason it is very important to do the pre-infusion, which basically consists of using twice as much water for the amount of coffee we use or, since I personally like to use three times as much water, BEWARE! I do not recommend exceeding more than three times as much as it can be negative for our drink, leading to more progress in the extraction than necessary, for example: if we use 18 grams of coffee for a v60, the pre-infusion using twice as much water would be 36 grams of water, but as I said, I like to use triple that, so we would use 54 grams of water for 18 grams of coffee. These data mentioned are simply examples and are only done at the time of pre-infusion.
Okay, but why do we do this?
Simple, in this way what we are doing is moistening the coffee bed, causing most of the gases to escape and preventing this from interfering when preparing our filter, causing channeling or leaving areas without properly moistening, which if this happens can cause us leaving unbalanced and under-extracted drinks. Apart from moistening the bed, we must quickly move it with a spoon, a stick, etc. to help the water pass correctly through the entire area of the bed. There are mainly two techniques that help a lot with this practice, the first would be to do the (North, South, East and West) and the second way is to do a “bird nest” and then a small shake.
A “bird nest” is a technique in which a small hole is made in the center of the coffee bed, thus facilitating the passage of water to the bottom.
Here is a video so you can see the differences:
What about immersion?
On the other hand, I must say that the pre-infusion technique is really valid for percolation methods but for immersion methods... is it really worth it? I consider that doing pre-infusion in immersion methods is meaningless and really a step that we can skip, even becoming counterproductive and now I explain why.
In short, preinfusion is used to prepare the bed for better extraction and avoid setbacks such as channeling or leaving areas without properly moistening. Having clarified this, we enter the immersion part, doing pre-infusion in an immersion method, what is going to cause us is going to be a loss of heat when preparing our filter, it is not the same as 50 grams of water at 94ºC entering the contact with 18 grams of coffee at room temperature and on top of that we wait 30 seconds for 200 grams of water at 94ºC to come into contact with 18 grams of coffee at room temperature, the result in terms of preparing the coffee to make a good extraction It will be the same pre-infusion as without pre-infusion since since everything is immersed, the coffee is perfectly moistened in both ways. It's more! By pre-infusing in immersion we run the risk of having a bad practice and leaving some area without properly moistening during those 30 seconds, something that would not happen if we filled it entirely with water.
Conclusion: Stop pre-infusing immersion methods!
Below I am going to leave a video in which I have demonstrated how pre-infused and non-preinfused coffee give the same results.