Puck prep is everything you do between grinding and brewing. The goal is simple. You want water to flow evenly through the coffee. When it does not, you get channels. A channel is a crack or weak spot where water rushes through. It leaves some coffee over-extracted and some under-extracted. The shot tastes both sour and bitter.
This guide covers the tools and habits people use to avoid channels. You do not need all of them. Start with the basics and add one step at a time.
What puck prep is trying to do
A good puck has three qualities.
- It is even. The grounds are spread out with no clumps or dense spots.
- It is level. The surface is flat, so water meets it evenly.
- It is firm and uniform. The tamp compresses the bed without cracking it.
Everything in this guide serves one of those three goals. If a step does not help, skip it.
Start with clump-free grounds
Grinders make clumps, especially at fine settings. Clumps cause dense spots and gaps. Break them up before you tamp.
Many people use a WDT tool. WDT stands for Weiss Distribution Technique. You stir the grounds with thin needles to break clumps and mix the bed. Needles with a small diameter work best. See Pesado tools for one example.
In Everything You Need to Know: Pesado BD Twist WDT Tool Reveal, Hoon takes a closer look at a prototype WDT tool from Pesado.
A simple WDT routine:
- 1Grind into the portafilter or a dosing cup.
- 2Insert the needles to the bottom of the basket.
- 3Stir in small circles, then draw the needles upward.
- 4Finish by tilting and lightly tapping the side, if you need to settle the bed.
Tapping, no tapping, or WDT
Many beginners tap the portafilter on the counter to level the grounds. Tapping is easy, but it can also compact the bed unevenly and leave a dense layer at the bottom.
Hoon tested this in Tapping vs. No Tapping vs. WDT - Which Method Brews the Best Shot?. He looked at the impact of tapping, not tapping, and WDT on the espresso. Watch the video to see what he found.
Distribution tools
A distribution tool, sometimes called a leveler, spreads the grounds across the basket and sets the surface flat. Some use fins, some use a flat disk.
A leveler works best after WDT, so you start with an evenly mixed bed. Set the depth so the tool just touches the top of the bed. Spin it a few times. Then tamp.
In How to use distribution tool for Espresso, Hoon shows how to use a distribution tool.
Hoon also explores a different idea in No WDT | No Distribution | Hydroforming Is The "New Tamping". If you are curious about skipping classic distribution steps, it is worth watching.
Tamping
Tamping compresses the bed so water meets even resistance. The most important part is that the tamp is level. A tilted tamp leaves one side looser, and water favors that side.
A simple tamping routine:
- 1Place the portafilter on a flat surface or a tamping mat.
- 2Rest the tamper on the bed and check that it is level.
- 3Press down with firm, steady pressure.
- 4Lift straight up. Do not twist or wiggle.
Pressure is less important than people think. Once the bed is compressed, extra force does little. Be consistent and level, and you will do fine.
Does an expensive tamper help? In his tamper comparison video, Hoon compares a Force Tamper against a Normcore tamper. Check the video for what he found. The Normcore tamper page lists related gear.
Make sure the tamper fits your basket. A tamper that is too small leaves a gap at the edge. A tamper that is too large will not seat. For a 54mm Breville basket, a 53.3mm tamper is a common fit.
Puck screens and paper filters
A puck screen is a thin metal disk that sits on top of the puck. It spreads the water from the shower screen more evenly. It also keeps the top of the puck cleaner, so the shower screen stays cleaner.
A puck paper is a paper filter that does a similar job. Some people use a paper at the bottom, a screen on top, or both.
In Puck Screen and Puck Paper, Hoon covers puck screens and puck paper. You can also see the puck screen page.
Screens need cleaning. Coffee oils build up in the holes. In How to Clean a Puck Screen Using a Steam Wand, Hoon shows one way to do it.
A wet or soggy puck
After a shot, the puck should be fairly firm. A soggy, wet puck can have several causes, such as too little headspace or a poor dose for the basket.
In Soggy Espresso Puck: Why It Happens and How to Fix It., Hoon looks at why this happens and how to fix it.
A simple routine
If you want a place to start, try this.
- 1Weigh your dose.
- 2Grind into the basket.
- 3Stir with a WDT tool.
- 4Level the surface.
- 5Tamp level with firm pressure.
- 6Place a puck screen on top if you use one.
- 7Lock in and brew right away.
Taste and time each shot. If the shot gets more consistent, keep the step. If nothing changes, drop it.
Next steps
- Learn how baskets affect your puck in Espresso baskets explained.
- Troubleshoot with Fixing bitter or sour espresso.
- Look at modern espresso and coarse grinding.
- Browse Pesado tools and Saint Anthony tools.
- Explore the video library.
Written for this fan-built hub from Hoon's public videos; numbers are starting points, and your beans, grinder and taste have the final say.
