No single factor has a greater effect on the quality of your coffee than the grind.
In this post I’ll explain how to grind coffee beans both with and without a grinder, as well as discuss some of the finer points of coffee grinding:
(Of course, if you want all-in-one convenience, take a look at our Complete Guide to the Best Grind and Brew Coffee Makers, which have an integrated grinder!)
There are 2 ways to grind coffee beans with a grinder:
Let’s review each.
A blade grinder is similar to a food processor or blender, looking like a propeller with a rotating axis in the middle and blades shooting outward.
Essentially, blade grinders spin really quickly and your coffee beans into tiny bits.
This significantly reduces the quality of the grind because the resulting ground coffee isn’t consistent in size.
Some of the particles will be a fine, powdery dust. Others will be large chunks.
Plus, the high speed required to smash the coffee beans generates heat, which can leach away flavorful organic compounds and decrease the quality of the resulting coffee.
Why would anyone choose a blade grinder? They tend to be cheaper.
If you’re shopping for a coffee grinder, it’s burr or nothing, baby!
OK that’s not entirely true for everyone, but it is for me. I use a manual burr grinder and I love it.
A burr grinder functions by placing two rough, burred plates in close proximity and truly grinding the beans as they fall between the plates. You can adjust the gap between the two burred plates, which allows you to control the coarseness of your grind.
The result is a very consistent grind size.
The black knob on the bottom attaches to the screw in the middle, allowing me to tighten or loosen it to adjust my grind size.
As you can see, the design of this burr grinder ensures my coffee is ground consistently to the same level of coarseness.
Once the grounds are small enough to pass through the gap, they fall into a collection compartment (not shown in these pictures).
Technicality: Actually, conical burr grinders produce a bimodal grind, which means they produce 2 different grind sizes: your target grind size and a small percentage of fine grinds. This forum thread does a great job describing what’s happening so I’ll use their metaphor. Imagine breaking a cracker in half. You get the two halves, you but also get a little bit of fine cracker dust. The same thing happens with a coffee bean in a conical burr grinder. You get the split beans but you also get fine coffee bean dust. In the end you’re left with your desired grind size plus a little bit of fine dust. This makes it a bimodal grind.
There are two different choices you’ll have to make when purchasing a burr grinder:
Mine above is a manual, conical burr grinder.
Which one is right for you? It depends on your preferences. Here are some of the benefits of each grinder type.
This choice is pretty simple and comes down to cost vs convenience.
You can also look for a coffee maker with a burr grinder integrated, which cuts down on steps in the morning and takes up less space on your countertop.
Let’s take a look at the modes of action for flat vs conical burr grinders, courtesy of FreshCup.com:
This makes it seem like conical burr grinders are the no-doubt winners, but flat burr grinders have the most important factor in their favor: consistent grind size.
For more information about burr grinders, this YouTube video is a great resource.
OK, so you don’t have a grinder handy.
How will you get your fix?!
Try these 7 different methods:
This is the beginning of the coffee grinding options that I’ll politely term “less than ideal.”
Similar in style to a blade coffee grinder, you can use a blender or food processor to pound your coffee beans into submission.
However, I find it’s much, much harder to get anything better than a choppy medium grind by grinding your coffee beans this way.
Begin by adding a small amount of beans, blending on the “grind” setting. Adjust the speed until you get something resembling your desired grind size.
Much more classic looking than just about anything on this list, you could also grind your coffee with a mortar and pestle.
It’ll be difficult to achieve a consistent grind any larger than dust, but that makes this a great intriguing option for anyone trying to achieve a coffee bean powder for a Turkish coffee.
Just be prepared for it to take practically forever, and keeping beans from jumping out of the mortar bowl as you crush them probably will be annoying.
It’s better to use a ceramic set because it’ll be more resistant to the coffee’s oils.
We’re now leaving the realm of anything that could remotely be considered grinding.
Now we’re hammering.
Follow these steps:
A meat tenderizing mallet or anything with a large, flat, blunt head works best, but I suppose you can use any type of hammer-like object.
You won’t get a fine grind for an espresso, but it would work decently well for a French press grind.
Using the same logic — and process — as the hammer, you can use a frying pan to achieve your grind.
Not any frying pan will do, though. You’re going to want something with a little weight to throw around. If you’ve got a cast iron frying pan laying around, that’ll get the job done.
Sticking with the “put coffee in a plastic bag and crush it” theme, you could also use a rolling pin.
When all else fails, you’ve probably got a knife lying around, right?
No, I’m not suggesting you chop your coffee beans up into the grind size you want.
Instead, look for a butcher-style knife with a tall blade and use the flat side of the knife to crush your whole bean coffee.
It’s similar to how you’d crush a fresh clove of garlic.
Starbucks won’t do this but if there’s a non-corporate local coffee shop in your neighborhood, you could try bringing your beans and asking them for a favor.
Just make sure you’re really nice to the barista. Tip them a buck or two!
Pro Tip: Work some sad sap details into your story. Maybe your significant other just left you and took the coffee grinder, leaving you without the most important part of your life.
(By which I mean the coffee grinder.)
I’ve had times where I’m in a pinch and just need ground coffee of any kind, but generally you’ll want to choose a method of grinding with two factors in mind:
Below are the 7 different grind sizes and the type of coffee to which they’re best suited:
Two notes about this table:
The following image from Batdorf & Bronson Coffee Roasters is a great visual representation of the above table.
Grind size is vitally important to the quality of your coffee. Small changes to grind size (and consistency, noted below) can drastically affect the taste of your coffee due to 3 factors:
The table below shows how each factor is correlated with grind size:
Coarser grinds have less surface area and require more contact time with water. However, they also allow water to flow between the grains much more quickly, shown above with the higher flow rate.
Note that “Contact Time” can have 2 meanings:
Because of the higher flow rate with coarse ground coffee, you need more contact time. However, the higher flow rate reduces the observed contact time in drip brewers as water flows much more freely through the coarser grounds. The inverse is true for finer grinds.
Grind quality is so important that for most home baristas looking for a low- or medium-cost startup, the vast majority of their costs should be allocated to a proper grinder.
In the coarser vs finer table above we discussed how grind size impacts your coffee. One such variable was extraction rate.
When you brew coffee you’re trying to extract the best combination of compounds to yield a balanced, caffeinated brew. The following awesome graph by theconversation.com via LifeHacker shows the extraction rate of different compounds over time.
When mixing coffee grounds and hot water you’re trying to extract the proper amounts of volatile oils and organic acids to produce your ideal cup of coffee. Your goal:
If your contact time is off you’ll either overextract or underextract your grounds. What does each taste like?
For optimal extraction you want to mix your coffee grounds with water for the proper period of time, and each coffee grind size has its own optimal contact time (which is also dependent upon water temperature).
This is why grind consistency is so important.
Imagine you’re brewing coffee with 2 batches of grounds.
Batch 1 has grinds all of the same size, so we know the contact time for a great cup of coffee: 2 minutes with my Aeropress, including both bloom and plunging.
Batch 2 has grinds of 2 different sizes, each of which has a different optimal contact time:
We have a little bit of a dilemma here, don’t we? By my estimation we have 3 choices:
And remember when choosing your grinder, flat burr grinders will do a better job than conical burr grinders in achieving a consistent grind.
This is completely up to personal preference, but a good rule of thumb is 2 tablespoons (10 grams) for every 6 oz of coffee. For a bolder taste and stronger cup, use more ground coffee. For something milder or more subtle, use less.
The Specialty Coffee Association has more great information about coffee ratios.
Black Bear Coffee has a handy table with volumes of coffee and water for multiple serving sizes.
Just don’t grind more than you need. Why?
Coffee is best when it’s fresh, so I recommend grinding:
Coffee will begin to degrade as soon as it’s ground, and many connoisseurs believe it will have a noticeable decrease in flavor after about 10-14 days. Nothing bad will happen if you store your ground coffee longer than that, but it won’t taste as fresh.
Honestly, the jury is out on this one. I’d advise you avoid storing your coffee in the freezer for 2 reasons:
There isn’t one!
While espresso is best made with a fine grind, you can make a regular cup of Joe with that same grind, too.
Espresso isn’t defined by the type of coffee bean or grind. Instead, espresso is espresso because of the extraction process.
More specifically, true espresso is defined by the following criteria:
Nailing all of those criteria gives you an authentic espresso. Coming close gives you something close to espresso (but not quite a true espresso).