Espresso Puck Prep: The Complete Guide to WDT, Tamping, and Distribution

Puck preparation is everything between grinding and pressing the brew button. Poor puck prep is the number one cause of channeling, inconsistent shots, and sour/bitter espresso. Good puck prep is the cheapest upgrade you can make.

The Problem: Channeling

When water finds a path of least resistance through the coffee puck, it overextracts that channel (bitter) while underextracting the rest (sour). The result is a muddy, unpleasant shot. Channeling is visible as spurting or uneven flow from a bottomless portafilter.

Step 1: Dose Consistently

Weigh your dose every time. For a standard 18g basket, dose 18.0g ± 0.1g. An inconsistent dose means an inconsistent puck density, which means inconsistent extraction. A coffee scale is required equipment, not optional.

Step 2: WDT (Weiss Distribution Technique)

Use a WDT tool (thin needles, $15-25) to stir the grounds in the basket. This breaks up clumps from the grinder and distributes coffee evenly throughout the basket. Move the needles in circular patterns from the bottom up.

Impact: WDT alone can fix most channeling issues. It is the single highest-impact puck prep technique.

Step 3: Level/Distribute

After WDT, level the surface. Options:

• Finger sweep: Free, works fine
• Distribution tool: Spins on the basket rim, levels grounds automatically ($20-40)
• Stockfleth's method: Palm technique used by barista competitors

Step 4: Tamp

Apply firm, level pressure — approximately 30 lbs of force. The exact pressure matters less than consistency and levelness. A calibrated tamper ($30-50) clicks at a set pressure, removing the guesswork.

Key insight: Tamping does not affect extraction as much as distribution. A perfectly distributed, lightly tamped puck outperforms a poorly distributed, firmly tamped puck every time.

The Complete Workflow

1. Grind 18g into portafilter
2. WDT for 10-15 seconds
3. Level/distribute
4. Tamp once, firmly and level
5. Clean basket rim
6. Insert and brew immediately

Total time: under 30 seconds once practiced.