The standard range is 92 to 96 °C — off the boil rather than boiling.
Why not boiling
Water at 100 °C extracts too fast and reaches the harsh compounds before the sweetness has finished arriving. It also scalds the grounds on contact.
Boil the kettle and wait thirty seconds and you are in the right band.
When to go hotter
Light roasts. Dense and hard, they resist extraction, and 95 to 96 °C helps considerably. If a light roast tastes sour at 92 °C, temperature is worth trying before you grind finer again.
Coarse grinds. Less surface area needs more energy.
When to go cooler
Dark roasts. Already brittle and soluble, they extract quickly and turn bitter. 88 to 92 °C suits them.
AeroPress and long immersions. Contact time is doing the work, so 80 to 88 °C is common — and many AeroPress recipes go lower still.
The espresso exception
Espresso runs around 92 to 94 °C at the group, and it is far more sensitive because contact time is so short. This is what a PID controls.
Perspective
Temperature is a real variable and a smaller one than grind size. Four degrees is worth roughly one grind step. Get the grind right first.
Last reviewed 8 August 2026