Barista programming
GPU
Exe.Eyes Labs
Coffee boiler heating
A study of the La Marzocco Linea PB, three groups. Sound on is best.
La Marzocco Linea PB
La Marzocco · Linea PB · 3 groups
Three groups. Two boilers. A coffee boiler held to two tenths of a degree. Built by hand in Scarperia, outside Florence.
Hover to see inside it · drag to turn it
- Larghezza
- 950
- Profondità
- 590
- Altezza
- 530mm
02Heaffles
The Heaffles
edition.
Matte black, and a pour of red, cobalt and white wrapped round every side. La Marzocco powder-coats the PB to order in any RAL colour; Heaffles went further.
Hold the loupe over the panel: it runs warm
03Carrozzeria
Take it
apart.
Every part has a number in La Marzocco's catalogue. Point at one.
04Caldaie
Two boilers.
Two jobs.
1.3–1.5 bar · 4,000 W
9 bar, tested to 18 · 1,900 W
Steam wants pressure. Espresso wants a temperature that never moves. In a single-boiler machine the brew water runs through a heat exchanger inside the steam tank, and the barista flushes it before each shot. The PB keeps the jobs apart.
05Gruppo saturo
Saturated.
In 1970 La Marzocco's GS put the groups on the boiler itself: separate boilers for steam and coffee, and the coffee boiler's water filling the group. On the PB even the flow meter sits in the group cap, so the water never leaves the boiler's heat on its way to the coffee.
06PID · Caldaia caffè
95.8°C
±0.2°C
Each boiler has its own PID controller. The coffee boiler holds its setpoint to two tenths of a degree; Heaffles brews at 204.5 °F. Drag the setpoint and taste what a degree does.
sweet, balanced
07Impianto idraulico
Follow
the water.
- 01PompaA rotary-vane pump, 150 litres an hour.
- 02Preriscaldatore584 mm of pipe through the steam boiler: the water is warm before it reaches the coffee boiler.
- 03GicleurA 0.6 mm jet cut in synthetic ruby, which scale and erosion can't wear.
- 04Caldaia caffèFive litres of AISI 300 stainless, held at temperature by its own PID.
- 05GruppoThrough the Piero cap's flow meter and the shower screen. To the coffee.
08Bilance
Three
scales.
Under each group, a scale grid on its own load cell, built into the drip tray. The machine weighs every espresso as it runs.
0.0g
09Disegno
Drawn to
the millimetre.
101418 · Il Marzocco
The lion
on the gauge.
Florence's heraldic lion, a paw on the lily shield. Donatello carved the city's best-known one in pietra serena between 1418 and 1420. In 1927 the Bambi brothers named their workshop after him, and he is still on this machine's pressure gauge.
111927 · Officina Fratelli Bambi
The name.
Giuseppe and Bruno Bambi design, build and sell espresso machines by hand in Florence. The name they gave the workshop is on the front of this one.
1225 February 1939 · Patent
The boiler
lies down.
Giuseppe Bambi patents a machine with a horizontal boiler and its groups in a line. Nearly every espresso machine since has had that shape, this one included.
131970 · The GS
Two boilers.
Separate boilers for steam and for coffee, and groups filled by the coffee boiler itself: saturated. The first machine built that way, and the idea inside every Linea since.
141990 · Linea
Piero's
Linea.
Giuseppe's son Piero Bambi draws the Linea: a plain, straight steel body that became the machine of specialty coffee. The PB keeps its line.
152013 · SCAA, Boston
Named
for Piero.
The Linea PB: a lower body, new electronics and this three-button keypad, designed by and named in recognition of Piero Bambi. Built by hand in Scarperia, 30 km north of Florence, where the factory moved in 2009.
162026 · Toronto
1189 King
Street West.
Ninety-nine years after the workshop in Florence, La Marzocco Canada opens a showroom in Toronto, its second in the country after Vancouver. The grand opening was on 20 September 2026.
2026
25sbalanced
What espresso is.
The Italian standard for one certified espresso. Pressure forces water through a compacted bed of coffee; the crema on top is coffee oil and carbon dioxide, emulsified by that pressure.
- Ground coffee
- 7g± 0.5
- Water at the group
- 88°C± 2
- Pressure
- 9bar± 1
- Time
- 25s± 5
- In the cup
- 25ml± 2.5, crema included
Finer is slower.
Grind decides how fast the water gets through. Too fast and it pulls only the sour, thin part of the coffee; too slow and it drags out the bitter. Turn the grinder.
This Linea PB pulls shots every day at Heaffles. Try it there