How to Choose the Best Coffee Grinders
Out of all the factors which affect taste when brewing coffee, it’s the grind which has the greatest influence. This is for two important reasons: grinders help keep coffee fresh, and give you the ability to adjust coarseness.
The key to good coffee, as with good food, is fresh ingredients. Coffee beans are relatively volatile and will lose flavor as they age. To keep them as fresh as possible it’s important to minimize their contact with air.
So what does this have to do with coffee grinders? Well, when you grind a bean you’re exponentially increasing its surface area, leaving it extremely vulnerable to air. Once coffee is ground, bright and acidic flavors quickly disappear.
Within as little as 15 minutes much of this flavor is lost forever. This is why: to get the most out of your coffee you should always grind it immediately before use. Unfortunately, coffee brought pre-ground, no matter how well it’s packaged, will have already lost some of its flavor.
Different coffee makers require a different coarseness of ground coffee, which is usually dependant on how long the brewing process is.
For example: an espresso machine, which has a short brewing time (less than 30 seconds), needs a very fine powder-like grind; whereas a cafeteria, which has a longer brewing time (3-5 minutes), needs a much coarser grind.
Manufacturers of pre-ground coffee usually adopt a one-grind fits all strategy. They supply all their coffee with the same medium grind, what has been coined the omni-grind, and expect their customers to adapt their brewing methods accordingly.
With your own coffee grinder you’re in control over the coarseness of the grind. So if you find the coffee is not quite to your taste you can easily adjust it ready for next time. If it tasted bitter, a result of over-extraction, you can change the grinder to a coarser setting; and if your coffee tasted flat, a result of under-extraction, you can change it to a finer setting.
Considerations when Choosing a Grinder
The first consideration when choosing a grinder is usage. What type of coffee maker will you be grinding your coffee for? Espresso machines and cafeterias are at either end of the grind size spectrum, espresso being fine and cafeteria coarse; and some grinders will struggle to reach either end (or both ends) of this spectrum.
So first ensure that any potential grinder is capable of grinding for your needs. If you’re planning on using your new grinder for several different coffee makers, then you’re better off going with a stepped grinder (more on this below).
The next consideration is price. There’s a huge variance in price between coffee grinders, and as a general rule you get what you pay for.
If you have a tight budget then you’re better off opting for a hand grinder rather than a cheap electrical grinder (sub £60) as cheap electrical grinders tend to be unreliable and produce inconsistent results – that’s as long as you don’t mind using a bit of elbow grease to grind your coffee.
The vast majority of electrical grinders priced over £150 are designed for use with an espresso machine. Whilst most of these espresso grinders are capable of grinding for other coffee makers, they tend to be less consistent on coarser settings.
The last consideration is size. If your partner or housemate doesn’t share your love for coffee they may object to you taking over the kitchen with a large grinder. Most commercial grade grinders (£450+) are designed for the café setting and are too tall to sit on a kitchen worktop directly below a cupboard.
Burr vs Blade Grinders
Blade grinders are very similar to a food processor. They have a whirling blade which hacks through the coffee beans as they bounce around inside it.
The problem with blade grinders is that it’s impossible to control the coarseness of the grind. The blade cuts indiscriminately, cutting some beans into tiny pieces, while others remain relatively unscathed.
This inconsistency causes problems when brewing, as the tiny particles will over-extract whilst the large particles will under-extract.
Unfortunately, the two don’t counteract each other to make something tasty; alas it’s not that simple! Instead you end up with a flat and bitter coffee. For this reason blade grinders should be avoided.
Burr grinders on the other hand work in a completely different way. The grinding mechanism consists of two discs (or burrs), one stationary and one rotating, between which the beans are crushed.
To control the grind size the discs are set slightly apart with the grounds only able to pass through the discs by fitting through this gap. If they are too large they continued to be crushed until they can pass through.
The size of the gap between the discs is controlled by the settings on the grinder. If you change to a finer setting the gap between the discs will shrink, and with a coarser setting the gap will grow.
Burr grinders don’t produce a completely uniform grind size, rather a range of sizes. This is because there’s nothing to stop finer particles passing though the gap between the burrs.
So the grind setting essentially only controls the maximum size of the grounds. However, having said this, they’re still head and shoulders above blade grinders.