How to grind coffee beans may seem like a bit of a weird question to the seasoned home barista, but to the uninitiated this is a very understandable question, and a commonly asked one.
I do have to remind myself occasionally that not everyone is geeky about coffee ;-). Most of the coffee knowledge I now take for granted would have been a surprise to me maybe 10 years ago, when I was yet to catch the "home barista bug".
Anyway, if you're wondering how to go grind coffee beans for the best results, or maybe you're wondering how to grind coffee beans for a specific brew process, fear not, as you'll know this and more, by the time you've finished reading this article :-).
So let's deal with the main question first, literally how do we grind coffee beans?
With a coffee grinder ;-). OK, you knew that much, you weren't about to try to use a boulder were you?
Well, actually this is how coffee was ground in some countries for centuries, this and some form of mortar and pestle was traditionally used to grind coffee beans until the invention of the coffee grinder, relatively recently.
It was in Turkey at some time in the 1400s as far as I can tell, when some form of manual grinder was first used to grind coffee beans, and a couple of hundred years later various grinder designs were invented in Europe, these were all quite a bit different in design from modern burr grinders though.
It was actually a bloke called Thomas Bruff, who just so happens to have been Thomas Jefferson’s dentist, who submitted the first U.S patent for a coffee grinder. Thomas, or "Bruffy" as I'm sure his mates called him, had the idea for burrs with different sized teeth in order to basically chew coffee beans.
From what I've been able to figure out, it was this teeth related design which we have to thank for the modern coffee burr design, which basically work like teeth to chew up the coffee beans into as uniform pieces as possible.
Anyway, thankfully these days you don't have to use a boulder, or a mortar and pestle, you simply need a coffee grinder - but not all grinders are built equally, as I'll explain shortly.
Manual Grinders Vs Electric Grinders
You can choose to grind your coffee with either an electric coffee grinder, or with a hand powered manual coffee grinder. Both are just as capable, so which you'd want to go for is completely up to you.
Keep in mind that how fine or how coarse you need to grind your coffee will determine how long the grinding will take.
For this reason it's more common that people would use manual grinders for brew methods like filter coffee and cafetiere which require a more coarse grind, and it's more common for people to use electric coffee grinders for espresso, for instance, which requires a more fine grind which would take more time and effort with a manual grinder.
Blade Grinders Vs Burr Grinders
The best coffee grinders, in my humble opinion, are those that have "proper burrs" which chew up the coffee beans into uniform pieces.
Blade coffee grinders are very cheap, in some cases they can be cheaper even than manual grinders, and to be fair they do the job, but they don't do it very well - simply because they don't create uniform particles.
With fast spinning blades, coffee beans are hacked and smashed into bits instead of being ground into uniform pieces, the way that they would be with burrs which are properly designed to chew the beans into similar sized chunks.
Also, as you can move burrs further away or closer to each other, you're able to control the grind size this way. With blade grinders the only way to control grind size is by grinding for less for a more coarse grind, or grinding for longer for a finer "grind".
Personally I'd say using a blade grinder is better than buying pre-ground coffee, as I rate freshness as even more important than particle uniformity, but if you do have a blade grinder I'd recommend upgrading to a burr grinder at some point if you can, for a more uniform grind and more control over the grind size.
Note - Proper Burrs...
The cheapest electric "burr grinders" (Krupps expert, Delonghi KG79, Melitta Molino) don't have traditional burrs, instead they have flat, blunt "grinding wheels" which work more like rolling boulders over beans.
While these kind of grinders are probably a step up from blade grinders because at least you can move the burrs in order to adjust grind size, the particle uniformity is similarly all over the place as with blade grinders, because the beans are crushed rather than being "chewed" with the teeth of the burrs.
If you can, I'd recommend avoiding the blade grinders and these blunt grinding wheel grinders, and go for one with proper burrs - you can actually get proper burr grinders for a very similar price.
See my best coffee grinders post for a much more detailed explanation and lots of reviews.
How Much Do You Need to Spend on a Coffee Grinder?
If you're using manual brewing methods, such as Aeropress, cafetiere or filter, most people will find that they don't need to spend much money at all, whether you decide to go for a manual grinder or an electric grinder.
I'd say £30-£50 for a manual grinder, or £80-£120 if you want a really good manual grinder, and from about £50 and upwards for electric burr grinders.
As long as it has proper burrs, as discussed, I think that were manual brewing methods are concerned, most people probably won't experience much of an upgrade in cup quality from spending a lot more money.
I say "most people" - because the vast majority of people are what I'd refer to as "normal" coffee drinkers.
If you love coffee, but you don't currently treat it as a hobby, you simply enjoy the drink - it's likely that your palate won't be developed to the point that you would benefit much where cup quality is concerned, by spending several hundred pounds on a coffee grinder for manual brewing methods.
If you regularly enjoy cupping sessions, if you've been drinking speciality coffee for years and you have well-developed coffee palate, then it's likely that your palate will be sensitive enough to mean that investing more money in your grinder will lead to better tasting coffee.
If not, then there are still benefits to be had from spending more money on a coffee grinder, including durability, reliability, speed and ease of use, but until and unless your palate is sensitive enough, it's relatively unlikely that you'll be able to notice much improvement in the cup.
So all I would say is if you're buying a manual grinder, keep in mind that the smaller the burrs, the more time and effort it's going to require to grind. So something like the 1Zpresso JX with 48mm burrs is going to take less grinding time than something like the Hario Skerton or Porlex Mini and many other hand grinders that have around 38mm burrs or smaller.
Also, for manual grinders check the maximum grinding amount as some of the smaller ones have a max of 20-25g.
Grinding Coffee for Espresso
If you're grinding coffee for use with a traditional espresso machine, then the kind of grinder you'll need will depend on the type of espresso machine.
If it's a bean to cup espresso machine, you obviously wont need a grinder, as your machine will have a built in coffee grinder.
If it's one of the cheaper domestic espresso machines such as Swan Retro, Cookworks, Delonghi Dedica, Gran Gaggia, Gaggia Viva, Smeg ECf01(which I know isn't exactly cheap, but it's the same kind of basket) then what these machines have in common is that they have pressurized baskets, or pressurized portafilters.
What this means is that with this kind of espresso machine, you don't need to grind your coffee beans anywhere near as fine as you would have to with traditional baskets.
Higher end espresso machines that I'd usually refer to as being entry level home barista espresso machines such as the Gaggia Classic Pro and most of the Sage espresso machines, come with both standard baskets and pressurized baskets so the user can decide how to use their machine.
If you're using a machine like this, with a pressurized basket or pressurized portafilter, you don't need an espresso capable grinder, and most proper burr grinders starting from about £50 will do the job, as with manual brewing methods.
If, however, you're using a Gaggia Classic Pro or a Sage espresso machine, or any other traditional espresso machine with traditional non-pressured baskets, then you'll need an espresso capable grinder.
There are a couple of exceptions (Sage dose control pro, Iberital MC2, Lelit Fred) but usually espresso capable grinders start at around £200 at the very entry level, and ideally you should allocate a budget of two to three hundred pounds or even more for your coffee grinder.
For traditional barista espresso, the grinder is key, and I believe you should focus the majority of your budget on the grinder.
The difference your espresso machine choice will make to cup quality within a range of a few hundred pounds difference, for example, is probably going to be very small. The difference a few hundred quid spent on a grinder, however, can make a huge difference.
How Coarse or Fine to Grind Coffee for Various Brew Methods
Despite what you're likely to read online about very specific grind sizes for different brewing methods, it's actually very difficult to describe different coffee grind sizes, and it's also very difficult to suggest a grind size even for very specific brew methods.
The reason it's hard to describe is that there are no real descriptors that are precise enough.
For instance you'll find descriptions relating to the size of particles of sand, table salt, sugar and so on - but unless you go and get some sand, table salt or sugar and actually compare, do you really know the exact particle size of a grain of table salt or builder's sand?
But just a slight change in visible particle size can actually be a really big difference, so using vague descriptions like this I just don't think is helpful.
Also, it depends on how you're using your brewer, as different methods require a different grind size even with the same brewer.
You can use cafetieres the traditional way with a more coarse grind, or you can use them in a more modern way with a much finer grind and a longer brew time.
You can use an Aeropress in various ways, with various different grind size depending on the method you're using, and with filter coffee often a different grind size is required depending on the size of the brew you're doing.
So what I'd say is start off with this guide and adjust until you're happy with the taste of your coffee:
Imagine focusing in a camera, if you go too far one way you'll go out of focus, if you go too far the other way you'll go out of focus, if you get it in the sweet spot in the middle, you'll be in perfect focus.
I think this is a good way to learn to dial in the grind with any brew method, by imagining lemon juice sourness at one side and very dark chocolate or cocoa bitterness at the other side.
You're aiming right for the sweet spot in the middle, so your coffee doesn't make your eyes water through to sourness, or make you wince due to bitterness, and instead is as in the middle as possible.
So just start off with a grind using the rough guide below, and adjust accordingly.
If you're happy with the taste of the coffee, don't do anything.
If you don't like the way it tastes, try to understand why. Is it because it tastes sour, like lemon juice - or is because of bitterness, like shoving a spoonful of cocoa powder in your gob?
If it's sourness, this is a sign of under extraction, so you need to try to extract more from the bean.
This can be achieved by grinding finer, and/or by increasing the brew temperature, and/or with a longer brew time (for immersion brew methods such as cafeitere and Aeropress).
If it's bitterness, this is a sign of over extraction, so you need to try to extract less from the bean, which can be achieved by adjusting the grind coarser, and/or decreasing the brew temp, and/or reducing the brew time for immersion brew methods.
With that in mind, here's what I'd recommend as a starting point for your grind size.
Cafetiere: Start towards the more coarse setting on your grinder.
Large batch filter: Same as above.
Small batch filter: Start towards the middle of your grinder's range.
Aeropress: Start towards the lower end of your grinder's range if it's a cheaper grinder with a relatively small range. If it's a more premium grinder with a bigger range, start just below the middle or at the Aeropress range if it has one.
Stove top: As above
Espresso for pressurized baskets: As above
Espresso for standard baskets: Using an espresso capable grinder, you'll be able to use flow rate to determine whether you're dialled in. For example aim for your desired ratio (for example 1:2, 18g of ground coffee to 36g of espresso) in a brew time of 28-32 seconds, and if the shot time is under 28 seconds grind finer, if it's over 32 seconds grind coarser.
Just be aware that it can take a long time to get the extraction right with any brewing process, so it makes sense to stick with the same coffee bean for a while, at least until you think you're tasting the best possible results from that coffee bean.
Many people swap from one bag of beans to the next continually, right from the start of their exploration into freshly brewing freshly roasted coffee, and this can make the learning process much longer.
If you try everything with a coffee bean and you just don't like it, it may just be because that coffee bean isn't for you. With high quality freshly roasted coffee beans there should be a lot more flavour than in commodity coffee - which is the kind of coffee most of us are more used to.
With commodity coffee each different coffee is often just a slightly different grade of bitterness, it all tends to be roasted dark to hide taste defects and staleness, so this is why many people think "coffee just tastes like coffee".
That's actually not true at all, but when all the coffee you're consuming has been roasted particularly dark, and has been roasted who knows when, and has been sitting in a bag for possibly months by the time you get it, then yes all of that kind of coffee is going to be relatively indistinct by the time you brew it.
When you're using freshly roasted high quality coffee beans however, you may get a bit of a shock when you detect flavours you're not used to detecting in coffee.
You might even get some coffees that you really, really dislike because they don't taste like you think coffee should taste like, and that's because there are some coffees that are acidic and juicy, for example, which you might not have experienced before - and there are some coffees which have what you may find as peculiar taste notes including things like leather and even tobacco.
But if you stick with a bean for a while to give you the best chance of dialing in with your chosen brew method to the point that you're getting the best results possible with that bean, and then work your way through different beans, you'll end up discovering some amazing coffee beans which take your enjoyment of freshly brewed coffee to a whole new level!