Whether you’ve never ground your own beans before, or have done for a while and want to expand your coffee grind size knowledge, you’re in the right place.
Grinding up your own coffee beans is a hell of a lot more rewarding than buying pre-ground. Not to mention it opens you up to a whole other world of brewing coffee you didn’t even realise existed.
But knowing what grind size you need for your brew method, and how to tell whether you’ve under/over-extracted your coffee beans requires a couple of insights.
Luckily, you’re in the right place to find answers to your questions. We’ll look at why freshly ground coffee tastes better, what grind sizes there are, and what you need to look for in a coffee grinder.
- Why Bother Grinding Your Own Coffee Beans?
- Grind Size And Extraction
- The Grind Sizes
- A Quick Coffee Grinder Guide
- Coffee Grinding FAQs
- To Sum Up
Why Bother Grinding Your Own Coffee Beans?
I’d be lying if I said I never thought this too when I got told to grind my own coffee beans. But as it turns out, there are some simple reasons why grinding your own beans creates a much fresher and better quality brew.
What’s Wrong With Pre-Ground?
Nothing is wrong with it per se. It’s convenient as it already comes nicely prepared for us to brew, and we don’t have to invest in a grinder.
But the trouble lies in the flavour and freshness. Put simply, pre-ground coffee goes stale a lot quicker than whole coffee beans do, therefore losing their flavour.
The reason this happens has got to do with the 4 elements that rob coffee of their flavours, and the amount surface area that’s exposed. These elements are oxygen, light, moisture, and heat.
When coffee beans are ground down, there is a lot more surface exposed to these elements, speeding up the time it takes for your beans to go stale. There’s an art to storing your coffee beans to avoid this, but it’s almost impossible with pre-ground.
So Whole Beans It Is?
Yes. If you’re wanting to create the freshest, most flavourful brew you can, from the comfort of your own home, then yes. You don’t see cafes popping open a bag of pre-ground coffee do you? Well, there’s a reason for that.
There are other benefits to owning a coffee grinder too. As we’ll come to understand why soon, each brew method has a specific grind size. Grinding your own beans will give you all the freedom you need to try out different brew methods.
If you’re using pre-ground coffee, you’re limited to the brew methods that require the grind size of the pre-ground.
But don’t stress out about buying a grinder. There are some super cheap grinders that grind your beans down in less than a minute.
We’ll talk you through the best type of grinders to get and why further down. But first let’s dive into why grind size matters, and the relationship grind size has with extraction.
Grind Size And Extraction
Why does grind size actually matter, does it really make that much of a difference?
Why Grind Size Absolutely Matters
Simply put, the shorter the extraction time, the smaller the grind size needs to be.
Here’s another way to think of it. The more surface area of the ground up coffee beans that are exposed, the less time the water needs to extract all those flavour compounds.
But most importantly because you leave the coffee to brew for around 4 minutes before plunging down the filter. If the ground coffee was too fine, 4 minutes would mean your brew would be way over extracted. If it was too coarse, your coffee would be under-extracted.
We’ll get to what over and under-extracted coffee tastes like in a moment.
With an espresso the extraction time is 15-30 seconds. This is considerably less time than a French press. So using our rule above, will the grind size need to be more fine, or more coarse than a French press?
If you answered more fine, then you’re absolutely right.
An espresso uses a fine grind size and so the hot water that passes through the ground coffee doesn’t need long to extract all the flavours. If you were to use a coarse grind size, the espresso would be under-extracted.
Under-extracted Vs Over-extracted Coffee
In the perfect cup of coffee, you’ll experience all the flavours the bean has to offer, as well as a smooth and creamy texture.
Let’s quickly run through the effect water has on the ground coffee, and how it actually extracts the flavours.
Whatever method you’re using, as soon as the hot water hits the ground coffee, the extraction process begins. And the extraction process always goes in this order: fats and acids first, then sugars, and lastly the plant fibres.
From a flavour perspective, the order of extraction goes somewhat like this: sour/oily – syrupy/sweet – thin/bitter.
The fats and acids that are extracted first create some sour and salty flavours. They’re the simplest compounds to break down and so that’s why water is able to quickly dissolve them.
Stop brewing here and you’ve under-extracted your coffee. This will lead to a sour and salty coffee.
Although the fats/oils in coffee don’t taste amazing on their own, they do help create texture. They are insoluble, so they don’t break down, they just get washed out of the ground coffee. In fact, at the right angle you might be able to see an iridescent shine on the surface of your coffee. These are the oils.
Sugars are next. This is where your complex flavours are added to your coffee. The sweet caramel, chocolate, or nutty flavours that you tend to get in a dark roast end up in your coffee here.
Finally, the plant fibres start to break down. This is when you’re flirting with over-extraction. These fibres are bitter, dry, giving your coffee a sharp taste, and overpowering all the beautiful sweet and floral flavours you’ve just extracted.
Each brewing method has a unique extraction time, there is no ‘one size fits all’ approach. We’ve got an entire article on brewing methods and how to make the perfect cuppa with each. You can check that article out here: How To Brew The Perfect Cuppa
The Grind Sizes
Here are the different grind sizes and which methods each grind size is perfect for.
This is the largest that most grinders will go to, and looks like kosher sea salt, or ground peppercorns.
The only times you would need to go this coarse is if you’re using the cold brew method.
This is ideal for brewing with a French press. The grind is large enough to keep it from going through the filters, but small enough to extract a coffee in about 4 minutes give or take.
Also great for percolator coffee or a cupping session. Should be a similar size to fine sea salt.
Slightly finer than a coarse grind size. Perfect for a Chemex brewing method.
This is ideal for flat bottomed drip coffee makers, siphon brewers, or an Aeropress 3 minute or more brew time.
This is where you want to be for your pour over coffee, whether it’s manual or automatic. It should be about the consistency of sand.
For an espresso, this is where you want your grind size to be. It’s almost powder like at this grind size, which is perfect for the short extraction time of an espresso shot. Also great for an Aeropress with a shorter brew time, and a Moka pot.
It should be slightly finer than table salt.
Only if you’re using the turkish brewing method do you want to be going this fine.
A Quick Coffee Grinder Guide
Now that we’ve covered the grind size settings, it’s important you spend your hard earned money on the right coffee grinder. There are some you want to avoid, and there are certain features you should want your grind to include.
We’ll cover two topics. Blade vs burr grinders, and manual vs electric.
Let me just tell you straight off the bat, you want to get yourself a burr grinder, and not a blade grinder. I’ll get to blade grinders in a second, but let’s take a look at what makes a burr grinder the best.
Firstly, burr grinders allow you to choose your grind size. There are a couple of variations, but they basically work by having two burrs that have serrated edges. You can move these burrs closer or further apart from each other to reach the desirable grind size.
Secondly, the consistency of the grind. A consistent and uniform grind size means a balanced extraction.
This means that every single ground piece of coffee goes through the extraction process at the same time. So you won’t get some grounds having their plant fibres extracted, while some other grounds are still having their sugars extracted.
The burrs are often made from stainless steel too, which are much more durable than some of the blade grinders.
So you’ll get a more uniform grind, a customisable grind, and a more durable and reliable grinder. An overall, a better brew.
Now if you’re insistent on getting a blade grinder for some reason, or maybe it’s that you have one already in the house for herbs or cooking, then here’s what you need to know.
A blade grinder works by placing a metal bar at the bottom cylinder. The blade spins around really quickly smashing the coffee beans to pieces.
As you may be able to guess, this doesn’t create a uniform grind, and therefore you get an unbalanced extraction.
You also can’t adjust the grind size, so you get what you get, no matter what brew method you’re wanting to use. If you’re brewing an espresso, you really can’t use a blade grinder as the grounds will be far too coarse.
You may be able to get away with a blade grinder when using a French press, or an Aeropress, but again, the extraction process is going to be unbalanced, and you deserve better!
Manual or Electric?
There are pros and cons to both, but the biggest difference is the price.
Manual grinders are great. They’re portable, reliable, durable, and some people even argue they grind coffee with more flavour because there’s less heat generated by the burrs as they’re not going as fast. And as we know, heat robs coffee beans of their flavours.
The downside is that you’ll have to put a bit of elbow grease into your morning cup of coffee, and a bit of time. Some of the best manual coffee grinders can grind coffee in about a minute, but most take 2-4 minutes of manual grinding.
It does depend on how large/small you need your grind size though. Obviously the smaller the grind the longer it’s going to take you to grind the beans.
If this doesn’t bother you, then go ahead and get a manual coffee grinder. I love getting involved in the brewing process of my coffee, and I swear coffee tastes better when you work a little bit for it!
Electric coffee grinders are fast and convenient, and normally offer a few more grind sizes than a manual grinder.
If you’re short for time on a morning as it is, and you have the budget for it, then electric coffee grinders are fantastic. You can keep your beans loaded in the hopper (assuming the hopper protects your beans well), and get your brewing equipment ready while your beans are being ground down.
Coffee Grinding FAQs
We get asked quite a lot of questions with regards to grinding your coffee beans, so hopefully one of these answers help any queries you have. If not, just drop us an email which you can find at the top of the page!
How Do I Know What Grind Size To Use?
Remember the rule, the longer the extraction time, the larger the grind size needs to be, with a French press being one of the longest extraction times, and an espresso being one of the shortest.
You can find out exactly what grind size each brewing method requires using our in-depth brewing guide, which you can find here: How To Brew The Perfect Cuppa
Using your new found knowledge of under/over-extracted coffee, you can figure out whether you got the right grind size, or whether you need a smaller, or larger grind.
How Long Does Pre-Ground Coffee Keep Fresh?
Companies that are selling pre-ground coffee are going to tell you their pre-ground coffee will stay fresh for weeks, if not months.
This simply isn’t the case and you’ll realise that as soon as you sip that first coffee you make with freshly ground beans.
When coffee is ground up it instantly starts to oxidise, and the ground coffee at the top of the pile comes into contact with air more than the lower grounds do. This creates inconsistency, and therefore an unbalanced extraction.
So, I would say pre-ground coffee keeps at peak freshness for no more than 30 minutes to an hour. Beware though, when you start grinding your own beans, pre-ground will never be good enough again.
Do I Need To Grind My Coffee Beans Daily?
If creating the freshest coffee possible is the most important thing for you, then yes.
Even if it’s not, spending mere minutes each morning to freshly grind your beans is a small expenditure for the improvement in quality of your coffee.
If you grind up all your beans you’re going to use for the week all in one go, you may as well save yourself the effort and get some pre-ground.
Does A Fine Grind Create A Stronger Brew?
The finer the grind size the faster the extraction process is going to take place.
The term strong in coffee is difficult to define. Do you mean a strong coffee taste? Strong caffeine content? Plus it’s not just grind size that affects strength. It depends on the type of roast, acidity, and the region it was grown in.
Can I Use A Blender To Grind My Coffee Beans?
I mean, technically yes, but that doesn’t mean you should.
Blender will grind your coffee beans up worse than a blade grinder. I’d recommend you just buy pre-ground coffee instead of using a blender.
To Sum Up
If you want to improve the quality of your coffee, then stop buying pre-ground coffee, and start grinding up your coffee beans.
There truly is no better way to experience all of the incredible flavours coffee has to offer, than to grind whole coffee beans up yourself just before you brew.
I hope this guide has helped you to take the first step in grinding your own beans, and aided you at improving your at-home barista skills.