Coffee Log

tl:dr – Coffee bean hardness; an important factor when extracting those lovely flavours from our even lovelier beans. I break down three factors that can influence your coffee hardness: roast level, altitude, and processing. I’ll share the why behind the hardness which may help you find your sweet spot faster and with far less wasted coffee.

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Dialling in a coffee – that process that can be enjoyable or bit of a pain in the butt depending on your mood. You have to invest a little time (and some wasted coffee) to find the right combination of conditions to extract all those complex flavours in our new bag of beans.

But what affects the grind setting for your bean the most when dialling in? After scouring the internet, I noticed the three main factors which were…

1. Roast level (most influential)
2. Altitude
3. Process (least influential)

I think that all three of these things influence one big thing: our coffee beans hardness.

hardness : the ability of a material to resist deformation, scratching or penetration.

In layman’s terms, the harder a thing is, the more difficult it would be to break it, even at a surface level. A harder bean will require more ‘effort’ to break the bean. The increased effort can be achieved by grinding things finer. It will also mean that once a bean is broken, it will break more evenly. On the other end of the spectrum is a soft bean. Imagine that this bean is made out of a crumbly sand, it takes a light touch to crack it or break it in half – it may even break down into fines on its own accord.

But how does that list of three affect our beans hardness?

1. Roast Level

• Darker roasts have been roasted for a longer time and at higher temperatures.
• This roasting dries out your beans more, making them more porous (less dense), more brittle and less hard (softer).
• These softer beans need a coarser grind (less effort to break) because they will fall apart on their own a little easier.
• The opposite applies for lighter roasts: less time in the oven at lower heats – more dense and less brittle – beans are harder and needs a finer grind (more effort) to break.

2. Altitude

• This could also encompass geographic location as different regions specialise in certain varieties of the Coffea plant. Each variety has its own innate hardness. But we’ll focus on metres above sea level (MASL) only for this point.
• The higher the altitude (more MASL) the more dense the bean.
• This is likely due to the colder weather at high altitudes. Our Coffea plants grow slower and the beans mature slower in colder temperatures.
• The benefit to this slow growing is that there is more time for sugars and nutrients to accumulate, which will affect the flavour of our final fruit and bean.
• These more nutrient and sugar rich beans are, the more dense (harder) and a finer grind (more effort) is needed to break them. The opposite applies for lower altitude beans.

3. Process

• This does not have as much of a strict rule and correlation but it’s worth noting how leaving more sugar, oils or fruit content on your bean can affect hardness.
• If the process leaves a lot of sugars on the beans (e.g. honey, natural, semi-washed processing) this will result in more variability which will affect the final flavour and the hardness of a bean. A coarser or finer grind may be required.
• Compare that to processing that leaves little or no fruit, sugar or oils on the beans (e.g., washed process) – the beans will be more consistent and won’t need adjusting for that fruit content.

In summary, the harder the bean the finer the grind. It’s worth considering how the roast level, altitude and processing may affect your new bag of beans. I’d love to hear of any other reasons that you find affect your final grind.

Until next dialling in,

-Anita, Your Grind Guide.