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

The Art of Creating a Perfect Espresso Puck

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. As with the coffee bed, a complete puck doesn't necessarily mean the coffee tastes good, but whether the puck comes out intact does reflect, from the side, whether the coffee can taste good. That is because every step in tamping the coffee powder directly affects whether the puck can be extracted completely, and they are all key factors that determine the quality of the coffee.

Understanding the Channeling Effect

As we all know, the reason espresso machines can extract a large amount of substances from coffee powder with very little water in a short time is that 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 extraction. Because the coffee powder is ground very fine, the puck's resistance is very high. Under the "attack" of such enormous pressure and resistance, the inertia of the hot water makes it preferentially flow away along the easiest channels. If there are many such channels in a puck, the extraction becomes very uneven. The powder in the channels is fiercely extracted, while the places outside them get "not a drop of water," which in turn makes the coffee taste both bitter and sour - the taste of uneven extraction. This is the channeling effect that often occurs during espresso extraction.

Reducing the Channeling Effect

If you want to reduce channeling and let the hot water extract all the coffee powder as evenly as possible, we need to reduce the channels in the puck. To do that, we have to distribute the coffee powder evenly in the portafilter before extraction. This not only reduces channeling but also results in a complete puck after extraction.

In other words, a complete puck appears precisely because our operation has been standardized and reasonable. So today, FrontStreet Coffee will share how to make a perfect puck.

1. Choosing the Right Dose

FrontStreet Coffee has shared plenty about extraction before, so this section focuses on operational steps. The first thing to pay attention to when making a perfect puck is using an appropriate dose.

In previous articles, FrontStreet Coffee has written a great deal about portafilter baskets, because whether the amount of coffee matches the basket really matters. The amount a basket can hold has a limited range. For example, the basket capacity used by FrontStreet Coffee is in the 18-21g range. If we fill more or less than that, the coffee easily extracts unevenly. The puck filled in the basket needs to maintain a certain distance from the group head, and that distance can't be too far or too close. If it is too far, the hot water easily breaks the surface structure of the puck and forms more channels; if it is too close, the portafilter may not fit properly against the group head, or the puck may be so thick that it under-extracts.

These problems make the coffee prone to uneven extraction and make it hard for the puck to come out intact. So when making espresso, the first thing to watch is the choice of dose - try not to use doses outside the recommended range, unless other tools assist, such as a secondary dispersion screen.

2. Distribution

Once the coffee is ground, the next step is filling it evenly into the portafilter basket. But whether you catch the powder with the portafilter or use a dosing funnel, the powder ends up landing unevenly in the basket, with more in some places and less in others. Tamping it directly would lead to an uneven distribution and create channels.

So before tamping, we can use our fingers to do a simple distribution of the powder, moving the concentrated coffee to the places where there is less. Then, reduce the gaps in the puck by shaking and tapping the portafilter.

It's best to have a distribution needle. You only need to stir the powder a few times with it before tamping, which distributes the coffee evenly while breaking up clumps caused by static electricity - killing two birds with one stone. Once the powder is roughly distributed, we can use a distributor to do 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. That way, during extraction, because the force is evenly distributed, channels are more difficult to form. There is only one thing to watch here: whether the force applied is even. As with distribution, if we tamp with uneven force - heavy on the left, light on the right - we tamp out a puck that is low on one side and high on the other, which causes the hot water to concentrate on one side during extraction and leads to channeling.

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

This method makes it easier to tamp out a flat puck, so extraction is more even. Of course, you can also buy a calibrated tamper according to your "financial ability" - that way you don't have to worry about uneven force. When you have completed the steps above, just be careful not to knock the portafilter during the rest of the process, and fit it perfectly into the group head, which minimizes channeling. Finally, you can extract a complete puck, and the odds of the coffee tasting good go up considerably.

FrontStreet Coffee Recommendation

A puck pulls cleanly when the coffee beneath it behaves predictably, so the bean you choose matters as much as your technique. FrontStreet Papua New Guinea Paradise Bird is a specialty single-origin from the Paradise Bird Estate in PNG's Sigri region; because its flavor and texture are close to Jamaica Blue Mountain, many drinkers call it a "little Blue Mountain." It is a Typica variety, the same lineage as Blue Mountain, grown at 1600 to 1800 meters in volcanic soil - terroir that gives the beans a full inner density - and it reaches the AA high grade with plump beans and a very low defect rate. Combined with a triple washed fermentation, the cup is clean and pure with a prominent sweetness, and it is a fine choice for anyone who prefers coffee without acidity.

If you would rather have a nutty, brown-sugar profile with a little more structure, FrontStreet 2013 Yunnan Sun-Dried Typica is a clean cup where citrus and caramel interweave. Its medium-dark roast adds a touch of nut, chocolate, and brown sugar, with medium acidity and a well-balanced layering that shows the character of the Yunnan region. Although Typica is not the mainstream variety in Yunnan, as a key representative of Arabica in specialty coffee it is a bean any grower or pour-over enthusiast should know.