Why is coffee grind size important?
Coffee making is an art; every step requires careful attention to create the perfect cup – right down to the size of your coffee grounds.
We spoke to Henry Ayers, original co-founder of The Gentleman Baristas and All Things Bloom Coffee, to find out just what happens to your morning brew when you get the grind size right – or wrong. “How fine or coarse the grounds are directly impacts the time it takes for water to drip through,” he explains. “Think of a glass of sand versus a glass of pebbles. Pouring the same amount of water through each, you’ll see that water takes longer to pass through the finer particles of sand.”
Unsurprisingly, this has a direct impact on your drink’s flavour. Take espressos. These have short brew times, so to get the best from your coffee, Ayers says you need “a finer grind size to present more of a barrier for the water passing through, ensuring enough flavour is extracted in that short time”.
There are a few tell-tale signs to that let you know if you've got the grind right. According to Ayers, if your coffee is weak, watery or sour then the grind is probably too coarse, so try switching to a finer setting. With a bit of trial and error, you’ll be sure to find your Goldilocks grind.
What is a burr coffee grinder and are they better?
There are three main types of coffee grinders: blade, burr and manual. As the name suggests, with a manual, you have to do the grinding yourself, turning a lever to crush the beans. For that reason, electric blade and burr grinders tend to be more popular – it’s easier to select your preferred setting, and your beans are taken care of at the push of a button.
Blade grinders work in a similar way to food processors, spinning a blade to chop the coffee beans. Burr grinders, however, work like a pepper mill with the beans passing through two metal or plastic grinding surfaces to break them up.
As a general rule, burr grinders are often larger and more expensive than other types, but they also offer more control over the grind size, and therefore, the final taste of your coffee. Unsurprisingly, then, when asked which is better, Ayers is emphatic: “Burr! Always! Blade grinders are fine for spices as you get a mix of fine and big bits. But for a good tasting coffee, you need a consistent, even grind,” he explains.
“Adjustable burr grinders allow for more precision than blade models. As the burrs move together and apart, they create a small gap, and the particles can only leave the grinding chamber once they’re small enough to fit through that space.”
Deciding whether to go for a burr or not really comes down to your palate, go-to drink and budget, so think about how often you’ll be grinding beans and your brewing method before settling for the one.
How to choose the best coffee grinder
With the coffee grinders on our list ranging in price from £20 to £195, it’s important to know you’re ticking all your boxes. Here’s what to consider before you buy.
Hopper
Generally found on burr grinders, hoppers are containers for storing whole beans, and having one means you won’t need to load your grinder every time you use it. While a larger hopper can (obviously) hold more, leave them there for too long and you risk light compromising the taste of your coffee.
Instead, Ayers advises storing coffee beans in “a vacuum container in a cool dark place” to preserve the flavour. If you’re concerned about this though, some premium models boast hoppers with UV filters for this exact reason.
Settings
Burr grinders generally have lots of grind size settings. However, according to Ayers, “Really, a fine grind, a medium grind, and a coarse one are doable for most people. The only reason there are more grind sizes is so you can get an exact grind for certain coffees such as V60s, moka pots and AeroPress.”
As a rule, use a fine grind for espressos, a medium one for filter coffee and a coarse setting for a cafetière.
Blade and manual grinders don’t offer settings – you simply adjust the grind duration to alter the finished result.
Anti-static features
During the grinding process, the coffee grounds pick up an electric charge from rubbing against the metal burrs. The finer you grind the beans, the more static they’re likely to pick up (as they’re pushed up against the burrs for a longer period). This can be annoying because it can result in the grounds flicking onto the counter when you collect them, leaving a mess behind.
Some research suggests that static can impact the taste too. The grounds clump together, changing the way they interact with the brewing water as it passes through and into your cup.
It sounds very technical, but there’s an easy solution: look for grinders with anti-static features. These include magnetic catch cups that reduce friction or even ones made of glass – a poor conductor of electric charges.
If all else fails, some coffee afficionados believe a few droplets of water can stop a build up of static.
What's the best coffee grinder for beginners?
If you’re new to coffee grinding, the Amazon Basics Electric Coffee Bean Grinder is a great starter model. It’s our favourite budget pick and was extremely accurate when producing fine coffee grounds, which are great for espressos. The compact design means it’s easy to store, too.
But if you’re a coffee connoisseur and want the level of precision a burr grinder can offer, the Bodum Bistro Electric Burr Coffee Grinder could be a better fit. There are 12 grind sizes to choose from which should suit most styles of coffee, without overcomplicating it.
What's the quietest coffee grinder?
According to our lab tests, the quietest coffee grinder is the Fellow Opus Conical Burr Grinder, which registered at 73 decibels (about the same level as a vacuum cleaner). Note that some of the models we’ve tested reached over 90dB.