Brewing delicious coffee is no walk in the park. One particular aspect of getting the best out of your beans is the grind size of your coffee.
How coarse or fine you grind your coffee has a great impact on the flavour of your resulting drink.
Too fine and the coffee will be strong and bitter. Too coarse and the coffee will be weak and sour.
The fineness of your grind is also dictated by which method or machine you choose to brew your coffee with.
Brewers like commercial filter coffee machines require a much coarser grind size than espresso machines.
In this article, we’re going to answer the most common questions we hear about coffee grind size to help give you all the answers.
Why Does Grind Size Matter?
Before brewing, your freshly roasted coffee beans must be ground down into a fine powder in order to extract the right amount of flavour. Extract too much flavour and your coffee will taste harsh and bitter. Extract too little and it will taste weak, dull and sour. The amount of flavour you extract is all down to how coarse or fine you grind your coffee.
What is the Difference Between Coarse and Fine Ground Coffee?
Imagine pouring water into a glass full of sand vs a glass full of gravel – the water will hit the bottom of the glass much faster through gravel than it will through sand. This is a great way of visualising the difference between fine and coarsely ground coffee.
A coarse ground coffee will have less total surface area, making it hard for your water to extract all of the flavour. In espresso, a coarse ground coffee will not provide enough surface area to build up the right amount of pressure – the espresso will come out too quickly and not have enough time to extract enough flavour from the coffee.
A coffee ground too fine, on the other hand, will make it easy to extract all of the flavour out of the coffee including the harsh bitter compounds that you generally want to avoid. In espresso, the increased surface area will build up a lot of pressure causing the coffee to flow too slowly, resulting in a bitter taste.
What is Coarse Coffee?
‘Coarse ground coffee’ is a very general term for a coffee that is ground with larger particle sizes – think granulated sugar in appearance rather than icing sugar.
Confusingly, the word ‘coarse’ can also be used to describe a coffee that isn’t ground fine enough. For example, you may have ground a coffee quite fine for a shot of espresso, but you didn’t grind fine enough and the espresso brewed too quickly – so you could say that the coffee was ground too coarse.
In real terms, you might have still ground the coffee quite fine, but for your chosen brew method and recipe it was still too coarse.
What Happens if the Coffee is Ground Too Coarse?
For every brew method, recipe, and for each coffee, there is a target grind size that will taste fantastic and get the best out of your chosen bean. This is going to be slightly different for each coffee, and should therefore be found by using taste as a guide.
If your coffee is tasting sour, overly acidic or dull, you may not be grinding fine enough (aka, the coffee is ground too coarse). When this happens, the coffee does not have enough surface area exposed to the water to let you get all of the good flavour out.
In the case of espresso, a coffee ground too coarse will come out of the portafilter too quickly. A tell-tell sign of a coffee that is too coarse is a shot of espresso that finishes brewing faster than your target brew time, such as 26-28 seconds.
Grinding your coffee too coarse leads to sour, weak flavours but also a significant amount of wastage, as you aren’t getting all of the flavour from your grounds.
What is Coarse Ground Coffee Used For?
In general, coarse coffee grounds are used to brew coffee with brew methods that take a bit more time such as filter coffee, batch brew, french press or cafetiere, and cold brew.
As a good rule of thumb, the longer the water and the coffee will be hanging out together, the coarser you need to grind your coffee. For a 4 hour cold brew, you’ll be grinding significantly coarser than for a 26 second shot of espresso.
How to Brew Coarse Ground Coffee
In general, the best advice we can give is that if your coffee is ground too coarse, brewing too quickly or tasting sour and weak, you need to grind finer for your next attempt. This process of trial and error to find the perfect grind size is known as ‘dialling in’.
However, sometimes you won’t be able to tweak the grind size if you haven’t got access to a grinder that is easy to adjust, or if you’re brewing with a bag of pre-ground coffee. You can still adjust your recipe to get great tasting coffee even if it is ground too coarse.
In order to properly brew a coffee ground too coarse, you’ll need to increase the extraction in other ways. This can be done by brewing with a higher temperature, using more water, or stirring the brew when possible.
For espresso in particular, you can still get great tasting shots from coffee that is ground too coarse – you’ll simply need to increase the amount of water used to brew the espresso. The resulting shot might be a little weaker, resembling something like a lungo or ‘short black’, but will be more balanced in flavour having enough water to extract all the flavour.
What is Fine Ground Coffee?
On the other side of the coin is a finely ground coffee. The term is a little arbitrary, but you could picture anything from caster sugar to icing sugar in terms of particle size.
Fine grind sizes are best suited to coffee makers and machines with shorter brew times, like a 20-30 second shot of espresso.
Espresso machines need a finely ground coffee in order to operate properly, with the high level of resistance building up the pressure needed for brewing concentrated coffee shots.
Fine grind sizes are also very useful when you’re trying to brew very light roasted coffee. They require high extractions to get all of the flavour out of them. For this reason, the ideal grind size for filter coffee using a light roast can actually be a very fine grind.
How Fine Should you Grind Coffee?
This really depends on your brew method and the specific coffee you’re brewing. As a general rule, you should be grinding as fine as you possibly can in order to get the most amount of flavour out of your grounds.
However, there will be a limit to how fine you can grind.
Grinding finer and finer will continue to increase how much flavour you extract, and at some point you will hit a wall of harshness and bitter flavours. That’s when you know you have ground too fine and that you should dial it back a notch for perfectly balanced, well extracted coffee.
What Happens if your Coffee Grind is too Fine?
If your coffee is ground too fine, it’ll be difficult to get a well-balanced tasting cup of coffee. The total amount of surface area will be greater than optimal, meaning you’ll extract too much flavour from the coffee including all the bitter and harsh compounds.
In espresso, a coffee ground too fine can actually build up too much pressure and lead to a blown out puck with uneven levels of extraction, leading to bitter and sour flavours at the same time.
How to Brew Fine Ground Coffee
Finely ground coffee is best used for espresso, turkish coffee, aeropress or single-serve filter coffees.
If your coffee is ground too fine for your chosen brew method, it can be easy to get harsh, bitter flavours in the cup. However, it’s still possible to get great tasting coffee. You’ll just need to lower your extraction in other ways such as a lower temperature or using less brew water.
Grow your Coffee Brand with Bridge Coffee Roasters
At Bridge Coffee Roasters we’ve helped hundreds of businesses build or refine their coffee experience. From choosing the right commercial coffee machine, to choosing the right bean – or even starting with their own white label coffee brand.
Our consultation process is thorough across the entire coffee experience.