A Beginner's Guide To Coffee Grinder by James Hoffmann
1. The Theory of Coffee Grinding
Grinding coffee is essential for extracting flavour and is driven by three key concepts:
- Surface Area Exposure: Grinding coffee breaks the whole bean into tiny pieces, maximising the surface area water can reach to dissolve flavour, resulting in a more delicious cup.
- Freshness/Staling: Grinding exposes the coffee's surface area, which rapidly accelerates staling. Staling causes loss of volatile aromas, development of unpleasant flavours from chemical reactions, and rancidity from oil oxidation. The best way to avoid this is to grind the coffee immediately before brewing.
- Grind Uniformity: Ideally, all coffee particles should be the same size. Non-uniform particles (a mix of fine and large pieces) result in an unbalanced, unpleasant cup:
- Tiny pieces can add bitterness.
- Giant pieces can add sourness.
- Grind Size Control: The ideal grind size differs significantly by brewing method (e.g., very fine for espresso vs. coarse for a French press). Control over grind size, especially for espresso, is crucial.
2. Types of Grinders
The video categorises grinders into blade grinders and burr grinders, with a discussion on the benefits of hand versus electric models.
| Grinder Type | Description | Pros/Cons & Features |
|---|---|---|
| Blade Grinder | The cheapest option (around £20). Blades smash the coffee instead of cutting it. | Cons: No meaningful control over grind size, poor grind uniformity, creates many fines which lead to bitterness and muddiness. |
| Burr Grinder | Uses two cutting discs (burrs) to cut the coffee. The distance between them controls the grind size. | Types: Conical (cone-shaped burr spinning inside) or Flat (two cutting discs/rings). |
| Hand Grinders (Burr) | You do the grinding manually. | Pros: Better quality for less money than electric since there's no motor cost. Quality increases with price, moving from ceramic to metal burrs and better stabilization for uniformity. Cons: Requires effort and time. |
| Electric Grinders (Burr) | Uses a motor to spin the burrs. | Entry-Level/Filter Only: Cheaper motors spin faster, making them louder. They lack the power to grind fine enough for espresso. |
| Espresso-Dedicated Grinders | Require more substantial, powerful motors to handle the effort of grinding very fine. | Features: Often include step less adjustment (infinite control) to allow for the small grind changes required by espresso. They may also use a timer for consistent dosing. |
| Modern All-Purpose Grinders | Designed for single dosing (grinding only what is needed) and can grind for both espresso and filter. | Features: Focus on low retention (minimal coffee grounds stuck inside the machine). They use design (like a bellows) to clear the grinding chamber of residual coffee . |
3. Conical vs. Flat Burrs
While this is an esoteric discussion, there are perceived differences when chasing high-quality espresso:
-
Conical Burrs: Some believe the slight diversity in particle size offers more texture and body to espresso.
-
Flat Burrs: Tend to provide more clarity and sweetness, but perhaps less texture.