By Simon Gautherin

Brewing coffee can feel endless.

Every year there’s a new brewer, a new filter paper, a new pouring technique. It’s easy to think that the next tool will unlock the flavour you’re chasing.

But after years of competing, sourcing, roasting, coaching and obsessing over extraction — I’ve realised something simple:

Not all variables carry equal weight.

When I think about brewing, I visualise a pie.

And some slices are much bigger than others.

50% - The Extraction Core

Grind size. Brew Ratio. Pouring Pattern. 

These three variables are half the equation.

If this isn't right, nothing else matters.

 

GRIND SIZE

Grind controls resistance and surface area. It dictates how water moves through the coffee bed and how quickly compounds dissolve.

Too fine and you’ll over-extract bitterness and dryness.
Too coarse and you’ll get sourness and a hollow finish.

Every serious dial-in starts here.

 

BREW RATIO

Ratio determines strength. And strength massively influences flavour perception.

A coffee can be beautifully extracted but taste “wrong” simply because it’s too dilute or too concentrated.

Often what people describe as acidity or bitterness is just incorrect strength.

 

POURING PATTERN

Pouring affects agitation and evenness.

Uneven pouring = uneven extraction.

You can have perfect grind and ratio — but if your bed is channelled or disturbed aggressively, you’ll taste it.

These three together form the structural foundation of the cup.

 

35% - Water: The Silent Architect

Water is not neutral. It’s not just a vehicle.

It is an active participant.

 

TEMPERATURE

Higher temperature increases extraction speed and intensity. Lower temperature can enhance clarity but risks under-extraction.

A difference of just 2–3°C is perceptible, especially in lighter roasts.

 

MINERAL CONTENT

This is where it gets interesting.

Magnesium tends to highlight perceived brightness and complexity.
Calcium supports structure and body.
Bicarbonate buffers acidity.

Same coffee. Same recipe. Different water? Completely different experience.

Water doesn’t just extract flavour. It shapes how that flavour feels.

I've spent the better part of 10 years nailing mineral concentrates so this part of the pie is easy - introducing APAX Lab! I've created 4 mineral concentrate blends to help you create your perfect cup! You can shop them on Zest's website right now - Shop Here

My Konflux mineral concentrate just won SCA Best New Product 2026 (Coffee Consumables) at World of Coffee San Diego!

 

15% - The Peripheral Variables

These matter. But less than most people think.

 

TYPE OF BREWER

Flat-bottom vs cone. Immersion vs percolation.

Geometry influences flow and texture. But it won’t rescue poor extraction.

 

FILTER PAPER

Thickness affects clarity and body. Yes, you’ll taste the difference.

But if your grind is wrong, filter choice is irrelevant.

 

DRINKING VESSEL

A thick ceramic mug vs a thin glass will change aroma concentration and thermal retention.

It changes perception. Not extraction.

Why This Model Matters

When a brew tastes wrong, many people start adjusting the smallest slice of the pie.

They change dripper.
They change paper.
They change cup.

Instead, I ask:

Is the grind correct?
Is the strength appropriate?
Is the extraction even?
Is the water helping or fighting the coffee?

Only once the big levers are aligned do the smaller ones become meaningful.

 

PRECISION ISN'T COMPEXITY

There’s a misconception in specialty coffee that better flavour comes from doing more.

In reality, it comes from prioritising correctly.

Master the 50%.
Refine the 35%.
Then polish the 15%.

When you understand weight, you stop chasing variables — and start controlling them.

And that’s when brewing becomes intentional.