The importance of tamping coffee. Does it even matter?

Tamping is about pressing the coffee in the filter holder basket to achieve a uniform extraction. Correct tamping guarantees a uniform flow of water through the coffee, and uniform extractions are indispensable for extracting coffee with the best flavor.

When extracting espresso coffee (even with a manual machine), it is very important to tamp it correctly for two fundamental reasons:

  • We create a resistance to the passage of water during extraction, increasing the pressure up to 9 bars.
  • We create a uniform space between the coffee and the group of coffee makers. This space is filled with water, and as the pressure increases, the water descends in the form of a column, thus achieving a uniform extraction.
When the coffee is tamped, the extraction is uniform
When the coffee is tamped, the extraction is uniform

Use the correct size tamper

When tamping the coffee in the portafilter basket, we first need a tamper.

Not all baskets have the same size, but not all tampers will have the same size. Therefore, it is necessary to use a tamper of the same size as the basket we are using.

If we are talking about commercial espresso machines used in coffee shops, these have filter holders with 58mm baskets. However, domestic coffee makers tend to use slightly smaller baskets, with 57mm being the most common. But in smaller coffee makers, we can see baskets of even 46mm.

Use a tamper with a flat base

I still don’t understand why there are tampers with a convex base because when you tamp, the coffee puck is not flat but with a depression in the center.

When brewing coffee this way, the ground coffee in the center is usually over-extracted while the coffee in the periphery is under-extracted, resulting in a poor-quality espresso.

Do not use plastic tampers

Many domestic espresso machines have a plastic tamper among their components. As they are very light, they are also very unstable, making it very difficult to get the right pressure and leveling.

When you put pressure on one of these plastic tampons, they tend to move and bend, producing uneven and uneven pressure. A stainless steel tamper is not too expensive and is a safe investment for quality espresso.

What is the best tamper to prepare espressos?

There are many types of tampers with different shapes, designs, and materials. And this is fine since every barista has their style, and not all of them will be ideal for every person.

I recommend looking for a traditional tamper with a stainless steel base and wooden handle. As for the shape, the classics are still a safe bet. In the image below, you can see the one I use.

The classic tamper I use
The classic tamper I use

How to tamp coffee correctly

The tips I will give you below may vary from those that you may have seen in other articles or videos on the internet. But probably all of them are correct; each barista has their technique, and based on it, they will advise you differently.

Once you have weighed and ground the coffee you need for the extraction:

Step 1. Add the coffee to the basket evenly. You can help yourself with your fingers but never tamp with them.

Add coffee evenly to the filter holder basket
Add coffee evenly to the filter holder basket

Step 2. Now hold the tamper with your hand as if you were going to hold a flashlight, leaving your thumb and index finger on the edge of the tamper to feel the contact with the filter holder basket. See my hand in the next image.

Hold the tamper as if you were holding a flashlight
Hold the tamper as if you were holding a flashlight

Step 3. Rest the filter holder on a flat, straight surface with your left hand (if you are right-handed), and position your right arm vertically over the filter holder basket with the tamper in your hand. The elbow should form a 90-degree angle.

Position your arm vertically to the filter holder
Position your arm vertically to the filter holder

Step 4. Now apply just enough force on the coffee until it no longer goes down, without adding more pressure than necessary. With this pressure, you will have removed all the air between the ground coffee. Turn slightly with your fingers in contact with the edge of the filter holder to ensure it is level.

Feel the edge of the filter holder with your thumb to level it
Feel the edge of the filter holder with your thumb to level it

Be careful not to exert unlevel pressure, as the coffee pod will not be horizontal, resulting in an irregular extraction. This problem is called “channeling” because over-extraction channels are produced through the coffee pod.

Completely flat coffee surface - perfect for coffee extraction
Completely flat coffee surface – perfect for coffee extraction

Important factors to take into account when tampering

  • Never hit the filter holder once the tamper has created the coffee puck. If this happens, cracks may appear in the coffee puck, and channeling may occur in the puck.
  • Never add coffee to a wet or damp basket, as this will cause the coffee to become damp, and the tamping will not work properly.
  • Tamping can only be done once; it does not matter how much you press the coffee. One single movement is enough.
  • If the tablet is uneven, do not try to add pressure on the opposite side, as you will create internal channels and obtain equally bad results. You can take this tablet out, decaffeinate it well and try to compact it again.

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