What’s the right grind for your coffee? The answer is simple–it’s whatever tastes the best to you. But if I just stopped now, there would be no reason for this notebook entry, so let’s forge onward!
Coffee grind size matters because you will always get the best results with the right grind for the brew method, accounting for all of the variables that can change the flavor of your coffee. It’s more than just about stronger or weaker brew, the character of your grind can mask or enhance certain flavor notes or make your coffee taste sweet or bitter.
To understand this, we need to talk a little about solubility and the stuff that’s inside a roasted coffee bean. Roughly speaking, there are sugars, oils, and carbohydrates. But delve deeper down the rabbit hole and you find organic acids (the kind that creates flavor), polysaccharides like glucose and fructose, lipids (another name for oils) and melanoidins, hydrocarbons, alcohols, aldehydes, ketones, esters, furans… you get the picture. There’s a lot of different stuff in a coffee bean that contribute to what we taste, smell, and experience in other ways when we enjoy a cuppa.
The important thing to understand when it comes to grinding coffee is that some of these compounds are more soluble than others. Time, temperature, and fineness of grind will influence how much of these different components gets extracted, and what ends up in your cup determines how your coffee will taste. Caffeine, for instance, is less soluble than other compounds, so by increasing brew time or by grinding finer (so that it takes less time for each ground to become completely saturated) the more caffeine will end up in your cup. At the same time, you will increase bitterness, because caffeine and other compounds that are also less soluble taste bitter. At the other end of the spectrum, flavors that taste sour and bright tend to extract first, so a coarse grind may bring out more citrus notes in your lightly roasted Kenya AA.
Ultimately, it’s up to you to find your best grind for what you enjoy. And those of us who tend to geek out on this sort of thing, well, we’re just a little off the edge, but we also know how to extract every bit of the potential flavor in a great coffee. So there’s that.
Let’s look at grind size. Here are some images to give you an idea of what different grinds look like, and how they are used. The grounds a on top of a US Lincoln Cent, so you can judge the size based on details in the coin. I use the coin’s date as a reference.
1,200 Microns and Larger
This is a grind that works well for cold brew coffee, as the cold water takes much longer to extract flavors, and the coarseness of the grind can introduce fewer solids.
Rolled between your fingers it feels like coarse beach sand.
1,200 to 1,000 Microns
This is a typical grind for French Press brewing, also known as immersion brewing. Produces a nice, flavorful cup and the coarse grind won’t pass through the mesh screen on the press.
Rolled between your fingers it feels like raw sugar.
This is a good grind range for coffee urns and percolators. Percolators aren’t very popular these days, but urns are often used in catering where a large volume of coffee needs to be prepared.
Rolled between your fingers it feels like granulated sugar.
This is the range where drip coffee gets tasty, with enough extraction to bring out the flavors, but not so much that you get increased bitterness.
Rolled between your fingers, feels like fine tablesalt. Does not stick together.
A finer grind is needed for K-cup pods due to the very short (30-60 seconds) brew time.
Rolled between your fingers, it feels like fine sand, almost powder, with a slight grit when just a few grains are pinched.
This is espresso range. The coffee is fine enough that it locks together to form a uniform mass that needs pressure for water to pass through.
Rolled between your fingers, it feels powdery, sticks together when you pinch it.
Under 200 Microns
This is Turkish coffee, where no filter is used. The coffee is boiled directly in the water and settles to the bottom when removed from the heat source.
Rolled between your fingers, it feels like flour and clumps together easily.
If only it was as simple as this chart implies…
The reality of grinding coffee is that it never fits neatly into these 200 micron ranges. Virtually all coffee grinders produce a wider distribution of grounds, from the coarsest to the finest. The coffee in these photos were taken by grinding coffee with a burr grinder, and then separating the grounds with a sieve shaker, a special device that separates out the coffee grounds from coarsest to finest by passing the coffee through a series of screens.
Take a look at the following example, of two grinders, closely calibrated to produce a drip grind, but with different grind distribution profiles.
Grinder A has slightly more focused grounds distribution with most of the coffee grounds distributed between 1,000 microns and 400 microns. Grinder B also has most of the coffee grounds distributed between 1,000 and 400 microns, but there is a large bump in the fine grounds under 200 microns. It is more than likely that the same cup of coffee brewed with Grinder B will have more bitterness than a cup brewed with Grinder A.
What can you do to improve your grind for more flavorful coffee?
While no coffee grinder is perfect, more expensive coffee grinders can boast a higher degree of accuracy in producing a narrow grind distribution with fewer “boulders” (grounds that are too large) and fewer “fines” (grounds that are too small). This is why your favorite 3rd wave coffee shop uses grinders that cost thousands of dollars. You can find good grinders for the home that won’t break the bank. If you ask around with your neighborhood coffee geeks, you will likely get several recommendations, and almost everyone will have something to say about Baratza grinders. My preference is for KitchenAid Pro Line grinders, because I prefer appliances that will outlive me over ones that have complex electronics and plastic bodies. You can also buy a set of sifting screens to screen out the boulders and fines from your coffee. Kruve sifters are useful for this, and while a sifter and set of screens cost more than some grinders, they will at least make a dramatic improvement on almost any coffee grinder.
But let’s be real. If you are happy with the coffee that. your current grinder produces, maybe you shouldn’t mess with a good thing. On the other hand, if you can’t figure out why the exact same coffee you enjoy at your local coffee shop tastes much better than when you use their beans at home, You might want to consider what your grinder is doing with your coffee.