Why your coffee grinder is more important than your coffee machine.
Is your coffee bean grinder more important than your coffee vending machine?
Have you been focusing your budget towards the best traditional barista espresso coffee machine money can buy but neglected the coffee grinder’s share of this budget?
A little-known secret in the world of coffee is that the coffee grinder is much more important than the commercial coffee vending machine you use.
Our Traditional Coffee Machines
As people say, ‘put rubbish in, get rubbish out’.
The coffee machine is essentially a large kettle. Yes, there is a bit more to it than that, but really, the coffee machine, simply put, passes hot water through the coffee grounds to extract the flavour and caffeine (unless opting for decaf).
The real magic happens in the grinder.
Let’s look at why.
The job of the coffee machine
If we look at the functions of the big, fancy looking
traditional espresso coffee machines you will see in many coffee shops and cafes, we can see the following
- A pump draws water from a water source (reservoir or plumbed in) and feeds into the boiler, under pressure, approximately 9 bars of pressure
- Water is heated in the boiler to a specific temperature, somewhere between 87° and 91°
- In this process, steam is created as a result of the pressurised, near boiling, water
- The ground coffee is dosed, approximately 14 – 21 grams for a double shot, into a portafilter, tamped and fixed into the grouphead
- The water is evenly distributed through the grouphead to flow through the coffee grounds in order to ‘pull a shot’ of espresso
- Around 35ml of water runs through the coffee for 20 – 30 seconds
- If timings and temperature are correct this should produce a perfect double shot, providing the grinder has done its job of course!
- The steam created in the heating process is then used through the steam wand to steam and texture the milk if necessary
The job of the grinder
Now we have looked at the function of the espresso machine, let’s explore the coffee grinder. Hidden in that small, unassuming piece of kit is the key to a good coffee;
- Dependant on the type of grinder – burr or blade – coffee beans will be ground in slightly different ways
- Blade grinders literally slice the beans up, this type doesn’t necessarily create the most uniform grounds, and therefore, not the best extraction
- Burr grinders crush the beans between two serrated plates, only allowing particles of a certain size to fall through the chutes, making uniform grounds, much better for coffee flavour
- In order to match the brewing method, you will need to adjust the distance between the burrs to create a finer or more coarse coffee ground
- You can either opt for an on-demand coffee grinder or a dosing grinder. The on-demand grinder is best for freshness of the coffee as it grinds the coffee as and when you need it. Dosing grinders are good for very busy situations, they will grind a batch of coffee in advance and store the ground coffee in a chamber ready for dosing out as you need it
So, what is it about the coffee grounds?
Now we have investigated the job role of the equipment, we can take a look at why the grind is the important part.
The idea behind grinding coffee beans is to break them down into particles small enough so that water can pass through the grounds and extract compounds from the coffee.
In order to get the best flavour and most efficient extraction, the grounds must be uniform in size, a small particle will take less time to brew than a large particle.
So, if water passes through a batch of coffee grounds that are uneven in size, the smaller particles will be over extracted, and the larger particles will be under-extracted.
In addition to this, even if all the grounds are the same size but too small, the water will take a long time to pass through the tightly packed particles, leading to over-extraction. And in the same respect, if all the grounds are larger, the water will pass through quickly, leading to under extraction.
We are starting to see how the coffee grind is a fine art
Over-extracted? Under-extracted? So what?
What do we mean by over-extracted and under-extracted?
- When coffee is being brewed, different compounds are extracted at different rates, so the amount of time the coffee is being extracted will determine the flavour of your coffee
- The first flavours to be pulled out are the fruity and acidic flavours, so if you under-extract your coffee, you may end up with a sour taste
- It is the bitterness and body that follow on from these flavours, so over-extract, and your coffee could be too bitter
How do I know what size grind I need?
As I mentioned before, this will depend on the method of brewing you opt for, along with your personal taste and on the coffee bean you are using.
As a general rule, these are the guidelines for the different brewing methods;
- Extra coarse – Cold Brew/Toddy
- Coarse – French Press, Duo Coffee Steeper, Percolators
- Medium-Coarse – Chemex, Clever dripper, café solo brewer
- Medium – Flat bottomed drip brewers, The Aeropress
- Medium-Fine – Pour Over Cones, Vacuum Pots, Siphon Brewers
- Fine – Espresso, The Aeropress, Stovetop Espresso Maker
- Super-Fine – Turkish coffee
All in all, you will want to experiment with the grind sizes to get the perfect coffee for you. Not everyone’s tastes are the same, so a certain element of adjustment may be needed to suit the wider audience.
Don’t be afraid to ask for feedback from your customers, they are your biggest asset and you want them coming back time and time again, so ensuring their happiness is your most powerful tool.
Check out our Coffee Grinder Top Tips Blog https://www.refreshmentsystems.co.uk/top-5-coffee-gri…best-differences/
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