Flat burr grinders function by using two horizontal rings of burrs positioned one above the other to precisely grind coffee beans.
Flat burr grinders are a popular choice for coffee enthusiasts seeking consistency in their grind size. Their unique configuration facilitates a specific path for the coffee beans as they are processed.
The Anatomy of a Flat Burr Grinder
At the core of a flat burr grinder are its burrs. Unlike conical burrs, flat burrs are designed as two rings of burrs that sit horizontal to the ground. Typically, one faces upwards and the other faces down.
Think of it like two parallel discs with abrasive teeth facing each other. One burr ring is usually stationary, while the other rotates. The distance between these two rings determines the fineness of the coffee grind. Adjusting this distance allows you to change the grind size, from coarse for French press to very fine for espresso.
Key Components
Here’s a simple breakdown of the essential parts involved in the grinding process:
| Component | Description |
|---|---|
| Upper Burr | A ring of burrs facing downwards. |
| Lower Burr | A ring of burrs facing upwards. |
| Motor | Powers the rotation of one of the burr rings. |
| Hopper | Container for whole coffee beans. |
| Catch Bin | Container for the ground coffee. |
The Grinding Process Explained
The operation of a flat burr grinder is a straightforward mechanical process:
- Beans Enter: Coffee beans are fed from a hopper into the gap between the two horizontal burr rings.
- Initial Grinding: As the rotating burr spins, the beans are drawn between the burrs and broken into smaller pieces.
- Fining: The beans are progressively ground smaller as they move outwards through the teeth towards the edge of the burrs.
- Exit: Once the coffee reaches the desired particle size set by the gap, it exits the burrs.
According to the reference, coffee beans drop between the burrs, are ground through the burrs and then drop again. This specific design means In this design, the coffee makes two 90-degree turns. The beans drop vertically into the horizontal burrs (first 90-degree turn), are ground horizontally between the burrs, and then drop vertically into the catch bin (second 90-degree turn).
This two-stage drop and horizontal grinding action helps in achieving a uniform particle size distribution, which is crucial for consistent coffee extraction and flavour.
Benefits of Flat Burr Grinders
- Consistency: Generally produce a very consistent grind size when properly calibrated.
- Uniformity: The horizontal grinding process helps ensure uniform particle distribution.
Understanding how these grinders work highlights their efficiency in preparing coffee beans for various brewing methods, emphasizing precision through their unique horizontal burr orientation and bean flow path.
