Espresso guides

Short, sourced guides to the questions behind the compatibility data — what the specs mean and what actually matters when you're buying a part.

• Espresso portafilter sizes explained — What size your machine is (54, 57, 58 or 52mm) and why parts don’t interchange across sizes.
• Bottomless portafilters — What a naked portafilter shows you about your extraction, and which one fits your machine.
• Single-wall vs dual-wall baskets — Non-pressurized vs pressurized — which one you want, and which baskets are which.
• Why 58mm baskets don’t fit Breville (54mm) — The most common fitment mistake — why Breville and Sage are 54mm, and what actually fits.
• Which tamper size fits your machine — 58, 57, 54 or 52mm — matching a tamper to your portafilter, and the tampers we cover.
• The E61 group, explained — What an E61 group is, why it means 58mm, and how to tell if your machine has one.
• IMS basket codes, decoded — What B702TH24.5M actually means — series, dose, shape, height, hole pattern and coating.
• Why “58mm” isn’t one standard — Two machines can both be 58mm and take different baskets — what the number measures, and what actually decides fitment.
• Parts that don’t exist — Does VST make a 54mm basket? Does IMS make gaskets? The parts people search for that aren’t made — and the ones whose fitment nobody has published.
• Groupheads explained — E61, saturated, lever and proprietary groups — and why shower screens and gaskets fit by group, not size.