Single vs Double Espresso Baskets
Confusion about 18g vs 20g+ baskets leads to extraction problems. Understanding headspace and dose matching prevents channeling and inconsistent shots.
⚡ Quick Answer
Match your dose to basket size with 2-3mm headspace after tamping. Standard double baskets (18g rated) work best with 17-19g doses. Triple/22g baskets handle 20-22g doses. Using too much coffee compresses the puck against the shower screen, causing channeling and uneven extraction. The stamped basket size is a guideline, not a maximum.
🎯 Key Takeaway: Basket size indicates optimal dose range, not maximum. Leave headspace for water to distribute properly. Over-dosing causes more problems than under-dosing.
Basket Types and Optimal Doses
Single Basket
7-9g
- • Tapered/conical shape
- • Harder to extract evenly
- • Only for true singles
- • Generally discouraged
Double Basket ⭐
17-19g
- • Straight-walled cylinder
- • Most consistent extraction
- • Standard recommendation
- • 18g is the sweet spot
Triple/22g Basket
20-22g
- • Larger diameter/depth
- • For lungo ratios
- • Requires bigger portafilter
- • Not all machines fit
Why Headspace Matters
The Headspace Rule
After tamping, you need 2-3mm of space between the puck top and the shower screen. This allows water to distribute evenly across the entire puck surface before pressure builds.
Check method: After tamping, insert a toothpick or paperclip into the basket. Measure how much space remains to the rim. You want 5-6mm to rim (2-3mm headspace after accounting for screen position).
Problems from Over-Dosing
- • Puck compressed against screen → edge channeling
- • Screw imprints on puck → uneven extraction
- • Difficult to lock portafilter → damaged gasket
- • Inconsistent shot-to-shot results
Why Avoid Single Baskets?
Single baskets are tapered/conical rather than straight-walled. This creates:
- • Uneven extraction: Water flows faster through the narrower bottom
- • Inconsistent results: Harder to dial in reliably
- • Channeling risk: Puck integrity issues at the taper point
Better approach: Use a double basket with a lower dose (14-16g) or make a shorter double and discard half. Many cafes serve "singles" that are actually just split doubles.