Grinding Coffee Beans the Right Way: A Complete Guide

Whether you’re brewing a delicate pour-over or pulling intense espresso shots, grind size matters. In commercial environments, where consistency and efficiency are non-negotiable, understanding how to grind coffee beans – and how to calibrate your grinder – can mean the difference between a good drink and a great one.

This guide explains why grind size affects coffee quality, how to choose the right equipment, and how to optimize settings for espresso – especially when working with super automatic machines like the Tango XP from UNIC Espresso.

Why Grind Size Affects Coffee Flavor

Coffee extraction is a balance of temperature, pressure, grind size, and time – where time is determined by the interplay of pressure and grind size. These factors control how fast water flows through the coffee bed and what compounds are extracted in the process.

• Too coarse, and water flows too quickly – resulting in under-extraction, sourness, and weak body.
• Too fine, and the water struggles to pass through – causing over-extraction, bitterness, and silty texture.

Each brewing method, from French press to espresso, has its own optimal grind size. For espresso, the window is narrow: a fine grind that delivers enough resistance to extract flavor, but not so fine that it causes channeling or slow flow.

How to Choose the Right Grinder

In a commercial setting, grinder choice is about precision, speed, and durability.

Traditional Espresso Machines

If you’re using a traditional setup, a separate commercial-grade grinder is essential. Here are the key considerations:

• Flat or conical burrs for consistency and uniform particle size.
• Micrometric grind adjustment to dial in the perfect shot.
• Programmable dosing to reduce waste and variation.

Super Automatic Machines

With super automatic espresso machines, grinding is integrated into the system.

UNIC’s fully automatic espresso machines feature high-precision 83mm flat burr grinders designed to deliver a uniform grind and stable extraction. The result? A balanced espresso shot every time, even at high volumes.

Matching Grind Size to Brew Methods

While this guide focuses on espresso, it’s helpful to understand where grind sizes fall on the spectrum.

How long to grind coffee beans depends on the grinder’s burr size and motor power – but in commercial setups, it’s more about calibration than duration.

Grinding for Espresso: How Fine Is Fine Enough?

Espresso is where grind size becomes most technical and most impactful.

Dialing in for Traditional Machines use

In a manual workflow, baristas adjust the grinder based on:

• Shot time (25–30 seconds is a typical benchmark).
• Flow rate (not too fast, not dripping).
• Crema quality and taste.

These adjustments are ongoing. Factors like ambient humidity, bean density, and roast date all affect grind setting. Baristas must test and calibrate daily.

Calibrating Super Automatic Espresso Machines

Super automatic machines like the Tango XP Duo or Solo handle everything, from grinding to tamping to extraction. But they still require initial calibration and ongoing grind size monitoring to ensure flavor consistency.

How to Calibrate Your Machine (General Process)

1. Start with Fresh Beans: use a consistent, medium-to-dark roast suitable for espresso.
2. Access Grinder Settings: use the machine’s touchscreen interface.
3. Dial In the Grind: adjust the burr gap slightly finer or coarser based on flow rate and shot time.
4. Run Test Extractions: evaluate crema, taste, and timing. A balanced shot should run in 25–30 seconds.
5. Save Settings: once calibrated, save the grind profile via the machine’s control system (Tango XP allows for programmable profiles).
6. Monitor Regularly: re-test when switching beans, if ambient conditions change, or if shot quality drifts.

The Tango XP’s integrated grinder, brew group motor, and ejection system are designed to prevent clogs, maintain stable tamping, and eliminate channeling – but the grind size still needs to be monitored by your team.

Final Tips for Commercial Espresso Grinding

• Always purge the grinder when adjusting to avoid cross-contamination between old and new grind sizes.
• Keep burrs clean and sharp as dull burrs lead to inconsistent particle size and slower extraction.
• Log changes: Track calibration tweaks during shift changes, especially in high-volume operations.

Knowing how to grind coffee beans for espresso – and how to calibrate your machine – is what separates great coffee shops from average ones. Whether you rely on a dedicated commercial grinder or an integrated solution like the Tango XP, attention to detail is key.

At UNIC, our machines are built to deliver high performance, reliability, and precision, but grind quality still starts with the right settings and calibration. Invest in your grinder knowledge, and your coffee will speak for itself.