What is the first thing most of us look at when we enter a specialty cafe?
For many, it’s the sleek, sexy espresso machine. Its suave powder coat or shiny glimmer takes center stage on the bar.
Others are drawn by the array of steampunk style brewing apparatuses – modern, artisan crafted stands caressing 1800s era glassware and momentous cold brew towers.
Or maybe you don’t look at the coffee gear at all when walking into a shop…if that’s the case, excuse our coffee geekery for a moment.
Here’s what we’re getting at: unless you’re a barista or coffee nerd, you probably don’t pay much attention to that unassuming coffee grinder hiding behind the espresso machine.
Why would you?
The grinder doesn’t really do anything besides crunch up beans. It’s not interesting, it’s not hip, and it’s not sexy.
But what if we told you that the grinder is the most important coffee brewing tool?
That it’s more important than the fancy cold brew towers and lustrous espresso gear?
Well, it is.
Using a formidable grinder is the most effective way to improve coffee extraction!
More than the brewing mechanism you use, what variables you manipulate, or what techniques you employ, adjusting the grind makes the most difference on your brew.
A good grinder is not a luxury. It’s a necessity.
Unfortunately, this isn’t common knowledge.
Getting into craft coffee ain’t cheap, and the majority of folks skimp on the coffee grinder budget.
This is something you should avoid at all costs. If you want good coffee at home, you’ll need a solid coffee grinding companion.
At the end of this article, we’ll feature a couple of worthy grinding suggestions.
The rest of the post discusses why grind is important, what you need to look out for, and how a good grind drastically improves brew quality!
The post is moderately in-depth, so make sure to read the “quick-looks” after each section. Enjoy!
I. A Deeper Look
Here’s how industry specialists define the coffee grinding process.
Scott Rao (SCA industry advisor and author of Everything but Espresso) explains that “grinding is the fracturing of coffee beans into many smaller particles”, and that the “purpose of grinding is to facilitate the extraction of soluble solids by exposing more particle surface to the brewing liquid” (7).
Ted Lingle (Executive Director at Coffee Quality Institute) defines grinding as “the process of reducing whole, roasted coffee beans to small particles…” (25) He says that “the goal in grinding is to create a uniform distribution of particle sizes within a specified range” (25).
This may seem like common sense. The more a bean is ground up, the more exposure it has to water…meaning more extraction potential!
In The Coffee Brewing Handbook, Ted Lingle writes that “cutting apart the coffee bean exposes much greater surface area…it shortens the distance from the center of each particle to the surface, thereby greatly reducing the distance (and time) the coffee flavoring materials travel to reach the coffee extract” (25).
All of the delicious flavor solubles, fats, and oils found in coffee become more exposed as the grind size gets smaller.
Thusly, a coarse grind requires more contact time with water than a fine grind to yield properly brewed coffee.
One thing to note is that grind size greatly depends on the brewing method used.
You wouldn’t want to use a coarse grind for espresso, and you probably shouldn’t use a fine grind with a Curtis Drip Brewer.
The finer a grind is, the more time the water will take to strain through the coffee bed.
Every barista should have a basic understanding of brew method / grind size compatibility.
Curious about how to grind coffee? Here’s an impromptu coffee grind chart:
[Coarse || Medium]
[Medium || Fine]
But remember that size isn’t everything.
QUALITY is the key to a proper and effective grind. We’ll touch on this in the next section!
I. Quick Look:
- Grinding is the process of dividing up the bean into smaller particles.
- The smaller the coffee particle, the more when the bean is ground up, it’s surface area is vastly increased; flavor solubles can be more easily extracted when brewing.
- Quality is more important than grind size (read on to next section).
II. Importance of Grind Quality
A grind’s quality is defined by how narrow (or uniform) its particle size distribution is.
Rao defines particle size distribution as “an arrangement of ground coffee particle sizes showing their frequency by mass or quantity” (67).
He informs us that “the narrower the particle size distribution, the more equally the particles will extract” (7).
In layman’s terms: particle size distribution is the difference in size between the biggest coffee particle and the smallest coffee particle.
If your grounds are moderately similar in size, there is more potential for a uniform extraction.
What you need to look out for are the fines and boulders.
- Fines- super small, powdery particles
- Boulders – large, chunky bits of bean
Fines and boulders are inevitable, but too many will lead to erratic flavors.
The fewer fines and boulders you have, the narrower (or more uniform) your particle size distribution will be.
If you have an excess of fines and boulders, your coffee will be both OVER and UNDER extracted.
The boulders won’t extract enough, leading to grassy, seed-like flavors. While the fines will lead to a coalition of astringent and bitter flavors in your mouth.
II. Quick Look
- You want a narrow particle size distribution. The more uniform your coffee grounds, the better quality brew.
- Fines and boulders are undesirable. You’re bound to have some, but too many will make your coffee taste OVER and UNDER extracted.
III. Grinding Effects on Brewed Coffee
Once again referencing Lingle, “grind is the most effective way to control the bitterness and astringency associated with over-extraction” (27).
More than the brewing variables of time and temperature, grind affects the end brew most.
The Coffee Brewing Handbook is chalk full of useful information and studies that concern brewing parameters’ effect on coffee.
For instance, coarsely ground coffee contains less amino acids than coffee brewed with fine grinds.
Constituents such as citric, malic, and acetic acids will also appear in lower concentrations from coarsely ground coffee brews.
Lingle also writes that other coffee components like caffeine and chlorogenic acids “clearly reflect the effect of grind size on the extraction of coffee solids” (28).
Many tests have shown that the manipulation of grind size affects acidity, bitterness, body, and astringency MORE than the time and temperature brewing variables.
Soooo… What does all this mean for you?
Don’t worry. You absolutely DO NOT need to memorize the acids and cellular components of coffee.
What you need to know is that there is a lot going on, and adjusting grind is the most reliable way of dialing in your brew. If you need to fix that bitter, burnt taste, start by changing your grind size!
Dialing in Your Cup of Joe:
- Start with the SCAA’s golden cup standard.
- Adjust grind.
- Once the coffee is somewhat close to your preferences, begin adjusting other brewing variables.
- These variables are time, temperature, agitation, brew ratio, and brew method used.
III. Quick Look
- On the micro level, grind affects a brewed coffee’s acidity, bitterness, body, and astringency MORE than other brewing variables.
- If you want to fix a coffee’s taste, start by adjusting grind. Once you have it almost dialed in, proceed to adjust other brewing parameters.
Ending with some Worthy Grinders
Here are some of our new favorite hand coffee grinders and electric coffee grinders! If you want to see our entire ultimate lists, be sure to check out our full review for hand grinders and burr coffee grinders.
There you’ll find 10 different manual coffee grinders and 15 different burr coffee grinders all stacked up against each other.
Burr Grinders ONLY
Only use burr grinders. They offer the best particle size distribution on the market.
If you want to grind coffee at home, the grinders above will suit you well. However, there are other great pieces of gear out there, so make sure to look around!
Before you buy your coffee starter kit, or before you upgrade that measuring scale of yours, consider the quality of your grinder.
Yes, a new Acaia scale will look sleek at your brewing station, but it won’t make your coffee taste that much better. Go to the root of the issue and refine your grind.
Good luck with your grinder search!
Lingle, Ted R. The Coffee Brewing Handbook. Long Beach, CA, Specialty Coffee Association of America, 2011.
Rao, Scott. Everything But Espresso. Scott Rao, 2010.