So, you want your coffee to taste even more delicious, sweet, and balanced. You want that incredible aroma and lingering aftertaste. And you want this every single time.

There are many variables that affect how your coffee tastes: time, temperature, brew device… But the most powerful tool in brewing better coffee, assuming you have good beans and good equipment, is grind size.

Let’s take a look at why grind size is key and how you can make use of it.

Lee este artículo en español Tamaño de Molienda: Cómo Mejora el Sabor de Tu Café

The different shapes and sizes of coffee: green, roasted, coarsely ground, medium ground, finely ground. Credit: Cafes El Magnifico

Better Grind Size, Better Coffee

The secret to great coffee lies in extraction. But what does this really mean? Well, it refers to the process of extracting the flavor and aroma compounds from your coffee beans into your hot water – and, in doing so, creating a delicious beverage.

However, not all flavor and aroma compounds are the same. Some add sweetness to your coffee, others bitterness; some add fruity notes and others astringency. And they all extract at different rates.

Todd Goldsworthy, Wholesale Account Manager at Klatch Coffee and US Brewer’s Cup Champion 2014 and 2016, tells me that coffee extracts in a predictable way. “First your acids, sugars, bitters, and then astringency,” he says.

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This means that, by controlling the degree of extraction, you can control how much of these elements make it into your beverage – or, in other words, you can determine the flavor of your coffee. This is the fundamental goal of recipe creation, whether you’re pulling espresso shots or crafting a pour over.

And grind size is a key part of this.

The Baratza Sette 270Wi grinds directly into the portafilter basket, dosing by weight, ready for pulling an espresso shot. Credit: Illimité Roasters

How Grind Size Changes Your Coffee’s Flavor

Several elements affect your coffee’s flavor: grind size, brew time, water temperature, the coffee beans themselves, their roast level…

Let’s define these quickly:

• Coffee beans: Not all beans are the same. Different origins, coffee varieties, and processing methods all have a different impact on the taste of your brew. (Want to learn more? Read all about it here.)
• Roast level: If under-roasted, your coffee will taste sour. Over-roasted, it’ll be bitter and smoky. But in between, there’s a world of difference: light roasts tend to be fruity and acidic. Medium roasts have more sweetness. And dark roasts have a lot of body with a dose of bitterness, and typically less complex flavors. (For this reason, most specialty roasters opt for somewhere between light and medium.)

  But it’s not just about flavor; the darker the roast, the quicker compounds are extracted. More on that to come!

• Brew time: The longer you brew, the more you extract.
• Water temperature: The hotter the water, the more you extract.

And then you have grind size, one of the most powerful tools for controlling extraction.

Alex Choppin is a Support & Coffee Specialist at Baratza, which makes high-quality coffee grinders. Many of Baratza’s products have won awards from the Specialty Coffee Association of America (now part of the Specialty Coffee Association), including the Sette 270W, which grinds by weight.

And as Alex tells me, “Grind size is one of the biggest factors in flavor when brewing coffee…. Exposing more surface area makes it easier for water to [extract more compounds] over the same period of time.”

Coffee ground with a Virtuoso  and brewed with a Chemex. Credit: Baratza

When Grind Size Goes Wrong

Choose the ideal grind size and you’ll have a delicious, sweet, well-balanced coffee. But if you get it wrong?

Will Frith is a Manufacturer Representative with Modbar, which creates modular brewing and steaming equipment. He explains that, if the coffee grounds are too coarse, “usually you will get a thinner-bodied and a less concentrated cup because fewer of the flavor compounds will be available.” Remember, the coarser the grind, the less surface area and so the slower the rate of extraction.

On the other hand, with too fine a grind setting, you may extract too much. Will says that you can end up with bitter and even ashy notes. “Flavors become more concentrated and difficult to pick up, and you can expect a muddy brew.”

Preparing to brew: kettle, cup, V60, and ground coffee. Credit: Ana Valencia

One-Grind-Fits-All? Not Exactly…

The ideal grind size will depend on many factors:

Your coffee beans: Since not every coffee tastes the same, when you buy new beans, you’ll want to adjust your grind setting to get the best possible flavors.

Your brewing device: Different brewing devices may require different grind sizes. Take espresso, for example: this requires a fine grind (although there’s still room for variation). French press, on the other hand, typically works best with a coarse grind.

There are many reasons for this difference. A French press is immersion brewing, i.e. it requires a long brew time, usually around four minutes. A coarser grind counteracts this by slowing down the extraction. Espresso, on the other hand, has a very short brew time, typically just 20–30 seconds, and uses pressure to force water through even the most densely packed coffee. This makes it better suited to a finer grind size.

Roast date: Never forget that coffee is an agricultural product and, just like bread or milk, is best consumed fresh. Once roasted, it will start to age and lose some of its flavors. To compensate for this, you can adjust your grind size. Alex suggests, “Increase your dose first, then consider fining up your grind, and you can liven up even month-old beans in a pinch.”

Roast levels: Will point outs that different roast levels don’t just affect which flavors you can extract. They also affect how quickly those flavors extract. Dark roasts are more soluble because they’ve exposed to heat for longer. This means extraction will be sped up. Generally, Will advises using a coarser setting for dark roasts and a finer setting for light ones.

Freshly ground coffee. Credit: Michael Haller

Grind Size: The Most Powerful Tool in Recipe Creation

But if grind size is just one of several factors that affect extraction, why pay all this attention to it? Because it’s arguably the most powerful factor.

As Alex says, “Grind size is going to be one of the biggest contributors to coffee flavor that you can easily control as a barista.”

And Will agrees. “Of course, there are many variables that will ultimately affect the outcome of a brew beyond grind setting, but a change in grind is the easiest way to make a repeatable adjustment to the brewing process.”

What’s more, grind size will affect your other variables. Take brew time and filter coffee. The brew time is the amount of time it takes the water to trickle through the grounds and out through the filter. And so, how fine or coarse the grinds are will impact on the time it takes.

“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 sand than it does through pebbles,” Alex says.

This means that you have less flexibility with grind size than you do with water temperature, for example. The wrong grind size would have a far more drastic impact on your coffee quality.

Coffee ground with a Virtuoso and brewed with a Chemex; a Chemex normally suits medium-coarse coffee. Credit: Baratza

Moreover, with pour overs and batch brew coffee, grind size will affect turbulence: how much the coffee grounds get moved around during brewing. And this also has a huge effect on extraction.

You want every coffee ground to be extracted to the same degree – or as close to it as possible. This will make coffee quality more controllable and more repeatable. This means that all the grounds need to spend the same amount of time in the water.

A little amount of turbulence is a good thing: it will move the grounds around, ensuring they are all exposed to the water. However, you don’t want the turbulence to push the grinds up the walls of the filter, where they will sit out of reach of the draining water and not be fully extracted. This will lead to sour notes in your coffee – and, unfortunately, it is more likely to happen with finer grind settings.

Find out more! Read What Is Turbulence & Why Does It Make My Filter Coffee Better?

The wrong grind size cannot just be compensated for just by adjusting other variables, because it has affects so many other factors. So, once you’ve confirmed your ratio of coffee to water, look to grind size. If you’re brewing filter/batch brew coffee, this will also dictate brew time. And only after that should you look at temperature, turbulence, and so on.

Freshly ground coffee. Credit: Baratza

Easy Ways to Improve Your Coffee Grinding

So now you know exactly how powerful the right grind can be – but how can you make sure that your grind size is as accurate as possible?

First of all, remember that consistency is crucial. If your grounds are different sizes, they will extract at different rates. The result? A lot of unpleasant flavors in the final cup, combined with difficulty replicating a good brew. Grinder quality matters.

But it’s not enough to just buy good-quality equipment. You also need to keep it in good condition. As Will says, “The grinder is mostly affected by the maintenance and cleaning schedule, so be sure to clean it regularly and replace burrs when needed (both according to the manufacturer’s recommendations, of course!).”

As for choosing the right grind setting, make sure you know the recommended size for your brewing method. Consider the coffee you’re brewing. And then try a setting that you think will match. Make sure to write down the recipe you’re using. Then, taste the coffee and take notes on it.

If the brew doesn’t taste like it’s been properly extracted, adjust the grind one setting at a time, keeping everything else the same. Of course, some grinders have more settings than others, giving you more control over your coffee and making this task easier. But no matter what you do, make sure you know what grind you’re using and that can replicate it later.

The Baratza Sette 270Wi has 270 grind settings. Credit: Baratza

Grind size is a powerful tool that can affect your coffee’s flavor in complex ways. Mastering this topic can be difficult. But fortunately, once you understand it, using this knowledge is simple.

As Todd Goldsworthy says, “Finding the right grind setting is simply about testing, tasting, documenting what you did, and changing one variable at a time, until you get a delicious cup.”

Enjoyed this? Check out Brewing Methods Compared: How to Make Coffee at Home

Please note: This article has been sponsored by Baratza.  

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