The Barista's Notebook: Grinding Secrets, Temperature, and Milk Art

May 4, 2026Carrera Café
★ Technique & Know-How

The Barista's Notebook

Secrets of grind, temperature, and milk art

Technical guide • 10 min read

Behind every perfect cup hides precise mechanics. Weight to the tenth, temperature to the degree, pressure to the bar. Our head barista opens his notebook for the first time.


The most underestimated variable

Before the machine, before the water, before the pressure, there is the grind. It decides everything. Too fine, the coffee burns. Too coarse, it leaks. Balance is a matter of seconds and grams.


Fineness scale — from coarsest to finest

Piston / Cold Brew
Coarse
Filter / V60
Medium
Moka Express
Fine
Espresso ★
Very fine
Ristretto
Ultra fine
★ Golden rule

If extraction takes less than 22 seconds, the grind is too coarse. More than 32 seconds, too fine. The ideal zone is 25 to 30 seconds for a standard espresso. Adjust by half steps, never more.

The physics of the perfect coffee

Espresso is as much a matter of physics as chemistry. Each variable interacts with the others. Changing the temperature without adjusting the grind is like leaving a curve at the wrong speed.


★ Machine parameters — Carrera Café

Water temperature 93°C ± 0.5
Pump pressure 9 bars
Pre-infusion 3 seconds at 4 bars
Extraction time 26 to 28 seconds
Yield (ratio) 1 : 2 (18g → 36g)
Machine La Marzocco Linea PB
Preheated cup Always, at 45°C

Why 93°C and not 90 or 96?

Technique

Below 90°C, acids remain suspended: the coffee is watery, acidic, without body. Above 96°C, bitter compounds over-extract in seconds. At 93°C, we are in the window where sweetness, body, and bitterness balance without fighting.

Cold zoneBelow 90°C
Ideal zone91 to 94°C
Burnt zoneAbove 96°C

Extraction method comparison

Espresso, filter, V60, Aeropress, cold brew. Each method has its parameters, strengths, and limits. A summary table to find your way without wasting time on pit stops.


Method Time Body Difficulty
Espresso ★ 25–30 sec Intense High
Ristretto 15–20 sec Very intense Very high
V60 / Filter 3–4 min Light Medium
Aeropress 1–2 min Medium Low
Moka Express 4–5 min Strong Low
Cold Brew 12–18 h Mild Very low
★ Our Preference

At Carrera Café, we believe espresso is the most honest method. It forgives nothing: neither bad grind, nor bad beans, nor bad pressure. That's why we chose it as the absolute standard.

Texture before the design

Latte art is the visible part of the iceberg. What really matters is the texture of the milk: velvety, without bubbles, at the right temperature. The design comes next, almost naturally.


01

Choose the right milk

Whole milk, minimum 3.5% fat. Skim milk doesn’t foam properly — too few proteins and lipids to form a stable microfoam. We use local milk from Saint-Isidore farm, delivered fresh every morning.

02

Target temperature

65°C, no more. At 70°C, milk proteins denature and the taste becomes slightly caramelized, less fresh. Use a thermometer at first. After a few weeks, the palm of your hand is enough: the pitcher should be hot but tolerable.

03

Incorporating air

Dip the steam wand at 45°, just below the surface. You hear a slight whistle — that's air entering. After 3 seconds, lower the wand and start swirling. Air should be incorporated at the start of heating, not after.

04

The whirlpool

Maintain a circular motion in the pitcher throughout the heating. The surface should stay smooth, shiny, like fresh paint. If bubbles appear on the surface, tap the pitcher on the counter and swirl to incorporate them.

05

The pouring — the real technique

Tilt the cup at 45°, pour slowly in the center from 8 cm height to get under the crema. At half fill, bring the pitcher closer and tilt to let the foam float and form the pattern. The rosette, the heart, the tulip: each has its own wrist angle.

Difficulty level of latte art patterns

Simple heart
Beginner
3-layer Tulip
Intermediate
Rosette
Advanced
Swan / Phoenix
Expert

Our exceptional beans

Each bean has a character, a story, an extraction window. Here are the three origins currently composing our rotation at Carrera Café.


Specialty beans, artisanal roasting, seasonal rotation.


Ethiopia Yirgacheffe — Natural

★ Signature

Black cherry, jasmine flower, bergamot note at the end of the cup. A natural coffee that feels like drinking a fruit. Used alone as a single origin espresso on Tuesdays and Fridays.

Altitude2,100 m
ProcessNatural
NotesCherry, jasmine

Colombia Huila — Washed

❤︎ Blend

Caramel, roasted hazelnut, soft and clean green apple acidity. The backbone of our Carrera blend. 60% of the composition. It brings the body and sweetness that Ethiopia alone cannot provide.

Altitude1,700 m
ProcessWashed
NotesCaramel, hazelnut

Brazil Cerrado — Pulped Natural

❖ New

Dark chocolate, hazelnut, long and silky finish. Very little acidity. This is the bean that gives our espresso its roundness on the palate and the aromatic persistence our customers recognize at the first sip.

Altitude1,100 m
ProcessPulped natural
NotesChocolate, silky
Come taste the difference

Settings are good. A cup in hand is better. Come to Carrera Café to taste what 93°C, 18.5 grams, and 27 seconds create when everything is perfectly aligned.

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