Is Pressing Necessary for Espresso? The Correct Method for Making Espresso!

The Art of Creating Perfect Espresso Pucks

Just as coffee enthusiasts pursue a deep, even coffee bed when brewing pour-over, most "perfectionist" coffee lovers also strive to extract a complete espresso puck when making espresso. Similar to the coffee bed, the appearance of a complete puck doesn't necessarily represent whether the coffee tastes good or not, but whether the extracted puck is complete will reflect from the side whether the coffee can taste good. This is because every step in tamping coffee powder directly affects whether the puck can be completely extracted, and they are all key factors that determine the quality of the coffee!

Understanding Channeling Effects

As we all know, the reason why espresso machines can extract a large amount of substances from coffee powder with very little water in a short time is because they use pressure-assisted hot water extraction. Under extraction pressure as high as 9 bar, a 58mm puck has to withstand pressure of about 240kg during the extraction process. However, because the coffee powder is ground very fine, the puck's resistance is very high. Under the "attack" of such huge pressure and resistance, the inertia of hot water will make it preferentially flow away from easy-to-flow channels. If there are many such channels in a puck, it will lead to very uneven extraction. The coffee powder in the channels is fiercely extracted, while the places outside the channels get "no drops of water," which in turn makes the coffee taste both bitter and sour - a taste of uneven extraction. This is the channeling effect that often occurs during espresso extraction.

Reducing Channeling Effects

If you want to reduce the occurrence of channeling effects and allow hot water to extract all coffee powder as evenly as possible, then we need to reduce the channels in the puck. To achieve this, we need to distribute the coffee powder evenly in the portafilter before extraction. This not only reduces the appearance of channeling effects but also results in a complete puck after extraction.

In other words, the reason why a complete puck can appear is precisely because our operation is standardized and reasonable. So today, FrontStreet Coffee will share how to make a perfect puck!

1. Choosing the Right Dose

FrontStreet Coffee has shared a lot about extraction before, so this content mainly focuses on operational steps. So first, the first thing we need to pay attention to when making a perfect puck is - using the appropriate dose.

In previous articles, FrontStreet Coffee has shared a lot about portafilter baskets, because whether the amount of coffee powder matches the basket is really very important. The amount of powder that a basket can hold has a range limit. For example, the basket capacity used by FrontStreet Coffee is in the range of 18-21g. If we fill more/less than this range, the coffee will easily have uneven extraction. Because the puck filled in the basket needs to maintain a certain distance from the group head, this distance cannot be too far or too close. If the distance is too far, hot water will easily break the surface structure of the puck, forming more channels; if the distance is too close, it will easily lead to the portafilter not fitting properly with the group head, or under-extraction due to the puck being too thick.

The occurrence of these problems will make the coffee prone to uneven extraction, and also make it difficult for the extracted puck to form. Therefore, when making espresso, the first thing we need to pay attention to is the choice of dose, try not to use doses outside the recommended range (unless there are other tools to assist, such as a secondary dispersion screen).

2. Distribution

After we grind the coffee powder, the next step is to fill the coffee powder evenly into the portafilter basket. But whether using the portafilter to catch powder or a dosing funnel, the final distribution of coffee powder falling into the basket will have some deviations, with more in some places and less in others. If tamped directly, it will lead to uneven distribution of coffee powder and produce channels.

So before tamping and distributing, we can use our fingers to make a simple distribution of the coffee powder, that is, use fingers to move the concentrated coffee powder to places with less coffee powder. Then, reduce the gaps in the puck by shaking and tapping the portafilter.

It's best to have a distribution needle. You just need to stir the coffee powder a few times with the distribution needle before tamping, which can evenly distribute the powder while breaking up coffee powder clumped due to static electricity - killing two birds with one stone. When we have completed the simple distribution of coffee powder, we can use a distributor to perform the initial "polishing" of the puck.

3. Tamping

The last action is tamping! Use a tamper to flatten the coffee powder, giving the puck a flat and smooth surface. This way, during the extraction process, because the force is evenly distributed, channels will be more difficult to form in the puck. There is only one thing to pay attention to here, and that is whether the force applied is even. Similar to distribution, if we apply uneven force during tamping, heavy on the left and light on the right, then we will tamp out a puck that is low on one side and high on the other. This will cause hot water to concentrate on one side during extraction, leading to channeling.

If you don't want to tamp out an uneven puck, then when tamping we need to pay attention to the position of our grip and the center of gravity of the applied pressure. Everyone can refer to FrontStreet Coffee's most common tamping technique: press one side of the tamper with the thumb and forefinger each, then wrap the remaining three fingers together with the palm around the handle, keep the arm vertical, and then apply downward pressure.

This method allows us to more easily tamp out a flat puck, making extraction more even. Of course, you can also purchase a calibrated tamper through your "financial ability" - this way you don't have to worry about uneven force application~ When we complete the above series of steps, just be careful not to let the portafilter bump during the subsequent process, and fit it perfectly into the group head, which can minimize the occurrence of channeling. Finally, you can extract a complete puck, and the probability of the coffee tasting good will be greatly improved~

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473