I have spent a lot of time learning about coffee the only way I know how, which is 100% saturation in the culture and the people who live and breathe the stuff. A lot of terms come naturally to me now (although I might still misuse a few), I use them in my blog posts and for those just catching up this can be overwhelming.

This is the glossary – if there is something you don’t understand in a blog post and it isn’t explained here then this is my failing, not yours. Please ping me on twitter @robashton


In the espresso machine this is where the ground coffee goes, there is a basket in the Portafilter and the water comes through under pressure from above and goes from the top of the basket through the coffee and out through the bottom and into the cup. (Google portafilter basket and all shall be revealed)


Think disagreeable, dryness, acrid flavours, quinine – often confused with sourness. Often get this with over-extraction.

Brew Ratio

How much water is being added to how much coffee? For example, 18g of dry coffee into 36g of wet coffee is a brew ratio of 1:2


The opposite of “muddy” is the best way I can describe this, if you can taste complexity in the form of acidity/fruit and it “sings” then there is probably a reasonable amount of clarity. Muddiness is easier to describe because it tastes and feels like drinking dirty mud.


When adding coffee to the portafilter basket it can be in a heap, lumped together or evenly distributed across the volume of the basket. Redistribution can help with this distribution and promote a more even Extraction.


How much dry coffee are you using in your brew recipe.


The grinder I use, it’s a commercial grinder originally designed for grinding spices – it has a huge set of burrs and the coffee drops vertically through them. It is an amazing thing and the resulting ground coffee typically extracts more than the average whilst still tasting clear and sweet.


Coffee brewed with a small brew ratio (typically less than 1:3) under high pressure in an espresso machine. This is what usually goes into your latte or flat white.

(EY) Extraction Yield

You’ve got a weight of dry coffee and you’ve got a weight of water going in, you’ve also got a weight of wet coffee at the end. Wet coffee is water with dissolved coffee in it – there is either coffee left in behind or coffee dissolved – extraction yield is expressed as a percentage of the coffee bean that was successfully dissolved. (Typically this is between 16% and 24% depending on the coffee)

Filter (Coffee)

Not espresso, everything else, chemex, aeropress, french press, etc.

Green Bean

Fresh from the mountains, the bean is the seed from inside the coffee cherry and it’s a green colour. Not edible unless you’re really desparate.


Takes the roasted bean and smashes it up into tiny little bits. There is a lot of variability in the design of these grinders and how evenly sizes the particles being created ar

Grind setting

How small are the particles you’re creating? The grind setting dictates this, usually referred to as “tighter” to have smaller particles (fineness) or “looser” than bigger particles (coarseness)


Basket goes into this and then the portafilter goes into the espresso machine – this is the metal bit with the handle.


Similar to brew ratio but also includes technique – such as the amount of agitation, the time involved and the temperature of the brew water.


Used for measuring the Total Dissolved Solids (TDS) in water (which can then be used to measure Extraction Yield)


The chaps that turn the green bean into something that can be ground up and used for coffee. They roast it via the medium of heat until it goes brown and then the joy comes out.

Roast Level

It’s a lot more complicated than this, but how dark is the coffee roasted? Typically this has always been dark (producing bitter burned flavours) but speciality coffee is far lighter – there are lots of roast levels and this one is easily googleable.


Tastes of burned toast, nuff said.


Usually a sign of under-extracted coffee, often confused with acidity – think the worst unripe lemons you’ve ever had.


Shorthand for espresso (Yo’ bro, spro bro? Totes bro).


Good espresso is sweet, not just a little bit – properly. It screams sweetness – this isn’t a complicated subject but most people haven’t had sweet espresso yet. (More commonly experienced at lower TDS (7-8%) probably because it’s easier to pick out).


Ground coffee goes into the basket, we “tamp” it to remove air from the “puck” so that when pressurised water hits it it doesn’t just run right through and extract nothing.

TDS (Total Dissolved Solids)

What percentage of the water is dissolved solids (in this case coffee), typical ranges are between 0.9% to 1.5% for filter coffee and between 7% and 12% for espresso.

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