Expresso

Chrome E61 group head and portafilter on a home espresso machine

E61 Group Head Explained: Thermosyphon, Pre-Inf...

The E61 group head is the most recognizable icon in the history of home and commercial espresso. Patented in 1961 by Ernesto Valente for the Faema E61 espresso machine, this...

E61 Group Head Explained: Thermosyphon, Pre-Inf...

The E61 group head is the most recognizable icon in the history of home and commercial espresso. Patented in 1961 by Ernesto Valente for the Faema E61 espresso machine, this...

Water for Espresso Machines: TDS, Hardness & Filters cover

Water for Espresso Machines: TDS, Hardness & Fi...

Updated August 2026 · Written by the Kairos Coffee team Water for Espresso Machines: TDS, Hardness & Filters Espresso machine water is the solvent that becomes your shot—and the chemistry...

Water for Espresso Machines: TDS, Hardness & Fi...

Updated August 2026 · Written by the Kairos Coffee team Water for Espresso Machines: TDS, Hardness & Filters Espresso machine water is the solvent that becomes your shot—and the chemistry...

Chrome E-style espresso group head with portafilter locked on a prosumer machine

Espresso Group Head Types: E61, Saturated, Semi...

Updated September 2026 · Written by the Kairos Coffee team Espresso Group Head Types: E61, Saturated, Semi-Saturated & Thermoblock Groups Espresso group head types describe how the brew chamber that...

Espresso Group Head Types: E61, Saturated, Semi...

Updated September 2026 · Written by the Kairos Coffee team Espresso Group Head Types: E61, Saturated, Semi-Saturated & Thermoblock Groups Espresso group head types describe how the brew chamber that...

Espresso machine pressure gauge and portafilter on a home espresso setup

Espresso Pressure Explained: 9 Bar, 15 Bar, OPV...

Updated September 2026 · Written by the Kairos Coffee team Espresso Pressure Explained: 9 Bar, 15 Bar, OPV & What the Puck Actually Sees Espresso pressure explained in one honest...

Espresso Pressure Explained: 9 Bar, 15 Bar, OPV...

Updated September 2026 · Written by the Kairos Coffee team Espresso Pressure Explained: 9 Bar, 15 Bar, OPV & What the Puck Actually Sees Espresso pressure explained in one honest...

Cutaway-style view of espresso machine boiler and group head on a home counter

Espresso Machine Boiler Types Explained: Single...

Espresso boiler types describe how a machine stores and moves heat so brew water hits roughly 195–205°F (90–96°C) at the puck and steam can still texture milk. The main home...

Espresso Machine Boiler Types Explained: Single...

Espresso boiler types describe how a machine stores and moves heat so brew water hits roughly 195–205°F (90–96°C) at the puck and steam can still texture milk. The main home...

Espresso machine retail box showing bar pressure claim beside a pulled espresso shot

9 Bar vs 15 Bar: What Espresso Machine Pressure...

Updated September 2026 · Written by the Kairos Coffee team 9 bar vs 15 bar on espresso machines is not a contest where the bigger integer wins. Roughly ~9 bar...

9 Bar vs 15 Bar: What Espresso Machine Pressure...

Updated September 2026 · Written by the Kairos Coffee team 9 bar vs 15 bar on espresso machines is not a contest where the bigger integer wins. Roughly ~9 bar...