When it comes to brewing coffee, one of the most important and sometimes overlooked components involves the coffee grinds. Having the most expensive coffee machine and the highest quality beans will not make up for inadequately ground coffee.
There are several ways in which grind size and quality can impact your end results. In fact, grind size is probably the most fundamental thing affecting your brew. If that’s wrong, your coffee will be.
Grind size should be your go-to parameter to alter, keeping everything else the same for making minor adjustments and tweaking your brews. It’s controllable, measurable, and consistent. You can easily taste the difference, with a finer grind being a little more extracted, a coarse one a little less.
Keep reading to find out why grind size matters and what size is best for your favorite coffee brewing method.
Why Coffee Grind Size Matters
Sure, many factors determine how your cup of coffee will come out: The quality of the coffee beans, your coffee brewing method, coffee-to-water ratio, temperature…
But, one factor that is often overlooked is the concept of extraction. And it’s important because even the best coffee maker can’t make up for it if you don’t understand the idea.
What Is Extraction?
Extraction is simply the process of transferring the flavors and other compounds (such as caffeine and acids) from the ground coffee to the water. It’s what happens while brewing when water passes through the beans or when the beans are immersed in water.
Now, coffee grind size is the most important component determining the extraction. The larger the surface area that is exposed and interacts with water the less time it takes to reach the desired level of extraction.
In other words, the finer you grind your coffee (hence more surface exposure), the shorter the brewing time you will need to get to the extraction level you aim for.
As a result, coarser grinds are more suitable for brews that take more time. On the other end of the spectrum, finer grinds are used for brews that take less time.
This means that you have to grind your beans to the appropriate size. Otherwise, you’ll end up with under or over-extracted coffee. If your grounds are too coarse, your coffee will turn out under-extracted. Not enough flavor is extracted, and a sour, acidic, or even salty taste will remain.
On the other hand, if your grounds are too fine, you’ll end up with over-extracted coffee. This happens when too much flavor has been extracted. The taste becomes unpleasant and overpowering, resulting in a bitter and hollow cup of coffee.
It can be helpful to think of extraction and grind size as sitting on a line. At the left-hand end of the line are coarse grinds and under-extracted coffee, and on the right are finer grind sizes and over-extracted coffee.
As you progress along the extraction line, different compounds responsible for different flavors are released. The first to come out are the sours and acids, followed by the sugars and bitters. To get a balanced profile in the cup, you should aim for just enough of the bitters to round out the flavor.
This is why under-extracted coffee tastes sour and can even be salty — it hasn’t yet hit the sugars extracted around the middle of your brew. Equally, over-extracted coffees taste bitter because the bitters have overwhelmed all of the more subtle flavor notes.
The aim is to get a balanced extraction. To hit that sweet spot, when all coffee notes unfold and manifest in a flavorful, well-rounded coffee.
What Do We Mean by Uneven Extraction?
An uneven extraction refers to one where some coffee grinds have extracted more than others.
This can be caused by channeling in some brew methods. Pockets of dry coffee come into contact with the water at different stages in the brew due to carbon dioxide escaping from the grounds and disrupting the water flow through the coffee bed.
Different things can cause channeling in different brew methods. Two of the most common culprits are not blooming properly in pour-over and batch brews or uneven tamping pressure in espresso.
Water is fickle and will always take the path of least resistance and doesn’t care about ensuring an even extraction for you and your coffee.
Another cause of uneven extractions is a poor quality of the grind. By this, we mean the presence of too many large chunks of coffee beans (commonly called boulders) and too many tiny pieces (called fines).
Cheaper grinders will produce more fines and boulders, whereas a better quality grinder will give you a nice, even, and consistent grind. Smaller fines will, of course, extract much faster than the larger boulders.
This means that in the same brew time, some of your brewed coffee will be bitter and over-extracted, and some of it will be under. The result is a very unpleasant cup of coffee. If you are served a really bad, ashy shot of espresso in a café, and you can’t tell if it has been over or under-extracted, it’s probably both!
What Grinder Should You Use?
There are two different types of grinders: Blade grinders and burr grinders. The way they crush (or rather chop in the case of the blade grinder) your coffee beans into coffee grounds makes a fundamental difference in the taste of your coffee. Burr grinders should always be your preferred choice.
Blade Grinder
In fact, blade grinder is probably something of a misnomer. Since they chop rather than grind your coffee, it is perhaps a little misleading to refer to them as grinders at all.
Although blade grinders might be a very economical option, it is less than optimal if you’re after the perfect cup of coffee. There are multiple reasons.
Firstly, the blade only works when spinning extremely fast. This causes heat and friction which in turn leads to the fact that the coffee won’t taste very fresh anymore. Instead it takes on a somewhat overcooked taste.
Secondly, the whirling blade slings the beans all over the chamber, leaving them in a mix of inconsistently sized grounds. As the grind size is uneven, you’ll likely have under and over-extracted coffee at the same time. Remember that ashy shot of espresso.
If you really want to grind your coffee fresh from whole beans rather than buying it pre-ground but are operating on a very tight budget, you might still get better results with a blade grinder. It can be a decent stop gap whilst you save up for something a bit nicer.
Burr Grinder
A burr grinder uses two revolving abrasive surfaces, the burrs, to apply uniform pressure and crush the beans consistently. As a result, it’ll provide much better control of the flavor extraction while brewing. This, in turn, will give you higher-quality coffee.
Even though it’ll set you back more than a blade grinder, it’s an investment well worth making.
When you think about a decent burr grinder, you have a choice between manual and electric. Hand grinders will get you the best results for the smallest budget. Something like a Hario Mini will get you started with ceramic burr grinding for the smallest outlay.
A top-quality hand grinder like a Comandante C40 will do as good a job as most electric grinders.
If an electric grinder is more your style, you have a number of choices. A great option for filter coffee would be the Ode by Fellow. It produces very even results and will give you great coffee, but it is worth noting that it won’t grind reliably fine enough for espresso.
If you’re brewing espresso regularly, it is worth investing in a good enough grinder that performs well at either end of the grind spectrum. You could certainly do a lot worse than a Eureka Specialita.
Coffee Grind Sizes
By now, you know that different coffee brewing methods require different grind sizes. In what follows, we will go over the seven grind sizes so that next time you know exactly how to set your grinder. For an overview, refer back to the coffee grind size chart.
Extra coarse
Extra coarse coffee grinds are very chunky and resemble the texture and size of peppercorns. As the size allows for little extraction, they typically spend an extended period of time in contact with water. They’re best used for cold brew coffee and cowboy coffee.
Coarse
The brewing method that is typically associated with coarse grounds is the French Press. As the grinds are submerged for a prolonged period, finer grinds will lead to over-extraction.
The size of coarse grounds is similar to that of sea salt, and a burr grinder won’t need long to achieve a coarse grind.
Medium-coarse
You’ll want to opt for medium-coarse grounds if you’re using something like a clever dripper, as it is a hybrid between an immersion and pour-over brewer.
If you like pour-overs brewed closer to the less extracted end of the spectrum, full of bright acids, this might suit here too.
Each pour-over method uses slightly different grounds, so you might want to experiment. The medium-coarse size is similar to rough sand.
Medium
With the medium grind size, we’ve reached territories of the most common grind setting. It’s the size that most people think of when they think of ground coffee.
You’ll want to use it as a good starting point for cone-shaped pour-overs like a V60, drip coffee machines, Siphon, and the AeroPress (with a slightly longer brewing time).
Medium-fine
Similar to the medium grind size, medium-fine grounds are typically used for pour-over brewers and the AeroPress (with a shorter brewing time).
If you like your pour-overs with a little more body and a fuller, more developed flavor, this is where you will want your grinder set.
It’s finer than sand but not quite as fine as espresso grind.
Fine
Fine coffee grounds are best for espresso, as the contact time of the water is relatively short. Arguably it’s one of the most sensitive coffee types when we talk about grind sizes as the whole process takes place under pressure, so you’ll want to get the grind right.
Alternatively, fine grounds are also used along with the Moka Pot and the AeroPress (with a very short brew time).
Extra-fine
Extra fine grounds have the consistency of flour and are used to brew Turkish coffee. You’ll want to set your grinder to the finest setting or use a Turkish coffee bean mill.
Now you know what grind best fits your preferred way of making coffee. Remember that your coffee grind is a crucial part of the brewing process. It’s a make-or-break for a rich, flavorful cup.
FAQ section
Is Coffee Better if You Grind Your Own Beans?
The answer to this has to be a resounding yes. Grinding your own beans will be the single biggest improvement to your home brewing you will ever make. Freshness is king with specialty coffee. The smaller the gap between grinding and brewing, the better the cup will be.
Does It Matter What Grinder You Use?
Choice of grinder can have a huge impact on final quality. As we discussed above, burr grinders are significantly better than blade ones as they will give you a much more even grind.
But it’s worth thinking about what brew method you will use your grinder for, as different styles of burr setup will give different results. This is a very contentious point amongst hardcore coffee fanatics. As a rule of thumb, conical burr grinders are a bit more forgiving and good for home brew filter.
On the other hand, if you are serious about your espresso, you may find you prefer the results you can get with a flat burr setup.
A lot comes down to budget, but remember that different grinders are built for different jobs.
Summary
Grind size and quality are some of the most important things to consider when searching for the best cup of coffee you can brew. It’s commonly held that, whatever your budget for your overall setup, at least half of it should go on your grinder to get the best results.
That should give you some idea of how important the grind is.
The main takeaways here should be that, whatever else you do, you should always try to grind your beans as fresh as you can. If possible, with a burr grinder that is fit for purpose. Your grind setting needs to be suitable for your brew method too.
Hopefully, you feel a bit more enlightened about the importance and nuances of grinding coffee after reading this article. You can always refer back to our chart for a reminder of where you should be with your grinds if needed. Happy grinding!
