If you are just learning to brew coffee with an AeroPress, the sheer amount of options at your disposal for fine-tuning your coffee can easily be a little overwhelming at first.
What is the Ideal AeroPress Grind Size?
All other factors equal, you’ll most likely be best served by using a coffee grinder (particularly a burr grinder) to get your coffee beans close to espresso grind size, which is roughly the coarseness of table salt.
Many AeroPress lovers will simply advise that finer is better.
AeroPress themselves recommend this level in a pretty simply put a blurb on their website.
They encourage a medium-fine grind, which is a finer grind than one might use to achieve a similar coffee flavor and strength in another coffee brewing device like, for example, a French press.
Pre-ground coffee you might purchase at your local grocery store is also fine to use, however brewing coffee with a slightly coarser grind will inevitably require more time to brew.
That’s because the larger your coffee grounds, the less total surface area that comes into contact with the water.
If you don’t increase brew time while using larger coffee grinds, you’ll inevitably end up with under-extracted coffee, which no one wants.
On the flip side, while using freshly ground coffee at medium-fine grind or extra fine grind size in your AeroPress coffee maker will produce a delicious cup of coffee faster, it will require more physical effort to press.
You can take our word for it though: it’s worth it.
Fine-Tuning Based on Type of Coffee
Having said all that, the equation can get a bit more involved depending on the type of coffee beans you’re using and the coffee flavor you want.
The advice above is the basic standard across the board, but you can achieve better results by tying grind size to different roasts.
Since darker-roasted coffee tends to be extracted faster in the brewing process, you may be able to offset that by using slightly larger coffee grinds.
Or, for a double effect, use that to your advantage and brew an exceptionally strong, bitter cup by keeping grind size as fine as possible.
Just remember that if you don’t reduce brew time when those two factors are already heavily leaning toward the ‘strong’ side of the scale, you’ll be asking for over-extracted coffee, which isn’t likely to be very satisfying for all your effort.
Coffee Bean Grind Size for AeroPress: Why It Get Matters
The Physics of Coarse Grind vs. Grind
Grind size refers to the size of individual coffee grounds. It directly determines how quickly water can absorb the coffee compounds from them, which results in our final coffee product.
The finer the grind, the more surface area there is for the water to come into contact with.
The more contact, the more absorption and therefore the less time you need to achieve the same flavor and strength.
Conversely, the coarser the grind, the longer the extraction process will take.
You also won’t get as much out of each scoop of ground coffee if you use a coarse grind, since more of the potent coffee substance that would otherwise react with your add hot water will be trapped inside the larger particles.
To achieve the best brew quality from your AeroPress, you must understand the importance of grind size.
The proper grind size will balance the extraction and provide the most flavorful brew.
There are several other factors that can affect grind size—such as the type of filter used, the water temperature, and the duration of your brew—but all these work in conjunction with grind size, which is arguably the most important factor to consider.
The Takeaway on Grinder Sizes
Finer grinds produce more flavor and less bitterness. Coffee beans that are too fine are over-extracted, resulting in a coffee that lacks distinct features.
A coarser grind may be acceptable if you’re brewing coffee in a French press, but even a medium grind won’t do your coffee justice in your AeroPress.
So what should you use? If you’re going “by the book” and taking broad strokes, sticking to a medium-fine grind coffee at the minimum will suit you for the most part.
If you have the strength and a good coffee grinder for your coffee beans, go with an espresso grind.
Our Personal Advice on Coffee Grinders
1. Use One
Don’t buy pre ground coffee and expect to be able to get anything better than French press coffee with it. You’re taking the time to research an extremely intricate variable to get the most out of your coffee recipe.
This small extra step unlocks that level of control and will allow you to experiment with different grind sizes.
2. Burr grinders are best
In our (extensive) experience, burrs are simply better than blades.
They’re not only more efficient, the coffee grind you’ll get using a burr coffee grinder will be far more consistent and reliable in producing coffee grounds accurately to your grind setting.
You’ll have more control over your coffee grind size, and it will allow you to get the most from both your coffee and the AeroPress.
At the end of the day, though, burr grinders or blades is a less important consideration than choosing to grind coffee beans you purchase whole rather than preground drip coffee to begin with, so start with what you have.
3. Electric grinders are even better
Get yourself an automatic burr grinder so you don’t need to exert physical effort to get that optimally fine coffee grind size.
If you care enough about your coffee to fine-tune your grind size find for optimal results, it’s likely to be an investment you feel pays off quickly.
The AeroPress is a relatively labor-intensive brewing method to begin with, so if you can automate your grinds, it’ll take a lot of physical effort out of the equation and give you an experience that’s one step closer to the all-in-one convenience and consistency of an espresso machine.
The right grind size can be the difference between a perfect cup of coffee and a weak, acidic cup. But remember that similar grind size alone isn’t the only factor you need to dial in when brewing with your AeroPress.
Despite our advice and even AeroPress’s own recommendation and comments, you can get away with using a medium grind size or even a coarse grind, if you adjust brew time and optionally, water temperature.
Experiment and find your grind
The best thing about AeroPress is that it encourages experimentation across the board, and so do we!
So while a finer grind may be more technically “correct” than a coarser grind, it doesn’t mean you won’t be able to achieve an impeccable cup of coffee using rock salt-sized chips of coffee.
Be sure to give different grind sizes a try, and when you find the perfect AeroPress grind setting for you, swing back around and let us know what recipe worked best for you.