How To Tamp Coffee
Ensure your coffee is subjected to the right kind of pressure
Once upon a time, the consensus was that the coffee grinds should be tamped at around 30lbs of pressure, which is rather difficult to consistently achieve and required either mechanical assistance or continued wondrous feats of strength.
This figure was used as a guidelines, and now many within the coffee trade now believe that around 8lbs of pressure is more than enough to compress your coffee properly.
Tamping is important as it compresses the grinds into an evenly distributed puck. During the extraction process – when hot water is forced through the coffee grinds at high pressure – the water will always seek out the path of least resistance, so it's integral to ensure that the grounds are tamped well and tamped evenly so we achieve a proper extraction.
By tamping we don't allow water an easy escape from the grouphead, instead it will soak up all the flavours in the roasted beans before exiting out of the grouphead spout – this process is known as 'coffee extraction'.
Therefore, to get a good extraction repeatedly we want to be consistent with our tamping. Getting an even tamp is much more important than a forceful one.
Grind your coffee into your group handle and give it a light shake to even the grinds out.
With a slightly curled finger, spread the grounds out so that they are level with the top of the handle’s basket.
Tamp twice. For the first tamp, apply a light amount of pressure to form a puck shape and for the second use give it a bit more force and press heavily down to remove any obvious spaces between the grinds.
Whilst applying the final bit of pressure, you can rotate the tamper through 720° to leave a smooth, even finish to the compacted puck of coffee – this process is referred to as the 'polish' – but it is not necessary. The importance here is to create a smooth, even puck.
Check the puck to ensure that there are no visible gaps or cracks.
Step by Step Guide
- Give your group handle a quick shake
- Place the group handle in an espresso tamping stand or on a clean flat surface or tamping mat
- Tamp with a light amount of pressure to compact the ground coffee a little
- Let the puck rest for a moment
- Now tamp the ground coffee again with around 8lbs of force
- OPTIONAL: Rotate the tamper to 'polish' the shot
- Withdraw to reveal a smooth, even and compacted puck
The 2009 World Barista Champion, Gwilym Davies, offers an alternative method known as ‘nutation’ — rotation around an axis.
This methods starts with an uneven tamp, which is achieved by rotating and angling the tamper through 360° in the filter basket, before a lightly pressured tamp evens the surface.
The theory here is that the coffee puck is packed tight in the centre and slightly looser around the edges, resulting in a more even extraction as water is forced outwards.
Once happy with its quality, place the group handle in your espresso machine and begin to make your espresso.