Commercial coffee grinders

Here's a step-by-step description of how a commercial coffee grinder works:

1. Bean loading: The operator loads whole coffee beans into the hopper at the top of the grinder.
2. Bean feeding: Once the beans are in the hopper, gravity or an auger mechanism inside the grinder pulls the beans downward towards the grinding chamber. (Some grinders have agitators to ensure a consistent flow of beans.)
3. Grinding process: As the beans reach the grinding chamber, they’re ground up by either burrs or blades, depending on the type of grinder.
4. Ground coffee collection: Once the coffee beans have been ground, they’re dispensed either into a dosing chamber below the grinding chamber (doser type) or a portafilter or container placed beneath the grinding chamber (doserless type).
5. Brewing: Finally, the ground coffee can be used for brewing.

The three main types of commercial coffee grinders are:

Blade grinders

• Use rotating blades to chop the coffee beans.
• Typically more affordable than burr grinders.
• Compact and easy to use.
• Produce a less consistent grind, resulting in uneven extraction during brewing.
• Challenging to achieve the desired grind consistency for specific brewing methods.
• Blades generate heat, which can adversely affect the coffee’s flavour.

Burr grinders

• Use two revolving burrs — conical or flat — to crush or slice the coffee beans.
• Produce a more precise and consistent grind size, allowing for better control over the brewing process.
• Produce a more uniform particle size, resulting in better extraction and flavour.
• Tend to be quieter during operation than blade grinders.
• Generally more expensive than blade grinders.
• Larger and occupy more counter space.
• Some lower-end burr grinders may have limited grind-size settings.

Manual grinders

• Portable and don't require electricity — ideal for outdoor catering or locations where access to power is limited.
• More affordable than electric grinders.
• Manual grinding is more laborious and time-consuming.
• Smaller capacity and thus unsuitable for grinding larger quantities of coffee beans.

Burr grinders come into two forms:

Conical burr grinders

• Cone-shaped burrs — one inside the other — crush the coffee beans.
• Known for producing even and consistent grinds.
• Favoured for espresso brewing due to their ability to produce fine, uniform particles.
• Tend to be more expensive than flat burr grinders.
• May have a slower grinding speed than flat burr grinders.

Flat burr grinders

• Two flat, parallel burrs cut the coffee beans.
• Capable of producing a consistent grind size, making them suitable for various brewing methods.
• Often have a wide range of grind-size settings.
• Prone to clogging if not properly maintained.
• Require more frequent cleaning and maintenance compared to conical burr grinders.

The size of an industrial coffee grinder is usually based on the capacity of its hopper (the container where you place the coffee beans before they’re fed into the grinder).

The capacity of most hoppers ranges from 500g to 2kg, but can be as much 7kg.

A larger hopper size allows for a greater quantity of coffee beans to be loaded at once, resulting in a higher capacity for grinding.

Some professional coffee grinders have multiple hoppers, allowing establishments to easily switch between different types of coffee beans (e.g. decaf) without the need to empty and refill a single hopper.

Another feature that determines a grinder’s capacity is its motor power: Grinders with more powerful motors (e.g. 800W or more) and higher grinding speeds can process larger quantities of beans more quickly.

By adjusting the distance between a grinder’s burrs, baristas can change the coarseness or fineness of the coffee grounds according to the specific brewing method or desired flavour profile.

(Blade grinders generally lack the fine-tuned control over grind size that burr grinders have; instead, the grind size in blade grinders is usually determined by the duration of grinding.)

Here are the most common mechanisms used to control grind size in a burr grinder:

Stepped adjustment: The grind size is adjusted by selecting predefined steps or settings on the grinder. Each step corresponds to a particular grind size, providing a limited but easily reproducible range of options.

Stepless adjustment: Offers infinite and continuous adjustment options, allowing precise control over the grind size. It typically involves a collar or dial that can be rotated to fine-tune the distance between the burr grinders and hence the particle size.

Micrometric adjustment: Similar to stepless adjustment but incorporates incremental markers or indicators to assist in achieving consistent grind-size settings. It allows for precise adjustments with more visual reference points.

Digital display: Some advanced industrial coffee grinders have digital displays that allow users to input specific grind-size settings or provide precise numerical values. This provides a more accurate and reproducible way to control the grind size.

Professional coffee grinders employ two main types of dosing systems to control the amount of ground coffee dispensed, whether it be a single shot, double shot, or more:

Doser grinder: In a grinder with a doser, the ground coffee is released into a dosing chamber below the grinding chamber. The barista can then pull a lever or rotate a dosing disk to dispense the desired amount of coffee into a portafilter or container. Because they grind coffee ahead of time, these types of commercial grinders are ideal for high-output coffee shops and restaurants.

Doserless / on-demand grinder: These grinders produce ground coffee as required, without pre-dosing or storing ground coffee in a separate chamber. The barista presses a button or flicks a switch to dispense a specific amount of coffee directly into a portafilter or container. On-demand dosing ensures minimal coffee waste and maximum freshness.

The choice of dosing system depends on factors such as workflow preferences, volume of coffee to be brewed, and desired level of convenience.

Traditional doser grinders are commonly found in high-volume environments, while doserless/on-demand grinders are popular among specialty coffee shops and cafes that prioritise grind-to-order freshness.