Part 1

Part 1: Mastering Coffee Cupping: Foundations of Sensory Science
Part 2: Mastering Coffee Cupping: Roast Chemistry and Processing Signatures
Part 3: Mastering Coffee Cupping: From Sensory Insight to Brewed Expression

Coffee cupping is often described as a standardised method of tasting, but at a higher level it becomes something much more precise. In modern speciality roasting and Brewers Cup preparation, cupping is a scientific exercise that allows us to understand flavour development, extraction potential, processing integrity and sensory structure before brewing variables ever come into play. This guide covers the aspects of cupping that are rarely discussed. It is written for those who want to master cupping, not simply perform it.

1. Cupping as Sensory Science

Most explanations of cupping focus on aroma, flavour and aftertaste. This is how most people naturally talk about coffee. At a professional level, though, cupping goes far beyond simply noticing whether something is fruity or bitter. It involves understanding the chemical and tactile components that shape how a coffee behaves in the cup, many of which everyday drinkers do not realise they are perceiving.

Volatile aromatic compounds, for example, change dramatically across temperature. What you smell when the coffee is hot may disappear entirely once it cools, and new aromas emerge as different molecules become active. The body of the coffee, which people often describe casually as light or heavy, is influenced by polysaccharide structures that activate the trigeminal nerve, the same system that lets you sense temperature and texture. Even acidity is not just sourness. Its quality depends on which acids are present, such as citric, malic or phosphoric, each of which produces a different sensation. Retronasal perception, the aroma you experience after swallowing or spitting, plays a major role in how clean or complex a coffee feels.

In other words, the goal of cupping is not only to notice what a coffee tastes like but to understand why it tastes that way. Professional cuppers are looking at the underlying structure of the cup.

• How sweetness supports acidity
• How texture carries flavour
• How volatile compounds shift as the temperature drops and
• How all of these components interact to create the final experience.

It is both scientific and sensory, but at the same time grounded in something most people intuitively recognise once it is pointed out: coffee changes as you taste it, and those changes tell a story.

2. The Variables That Professionals Control

Grind size and water temperature are the basics. Advanced cuppers also control:

• Water alkalinity, because bicarbonate ions buffer acids in the cup. Low alkalinity allows malic, citric and phosphoric acids to express clearly, while high alkalinity neutralises them and can collapse perceived acidity. Even a small change in bicarbonate concentration can shift the cup from bright and structured to flat and muted.

• Roast gas content, because freshly roasted beans retain high levels of carbon dioxide. Excess CO₂ inhibits extraction, masks sweetness and alters the release of volatile aromatics during cupping. Professionals often cup coffees within a controlled window of degassing to ensure the sensory data reflects the coffee rather than the roast gases.

• Grind friction heat, which affects particle size distribution as grinders warm up. Increased burr temperature produces more fines, raising extraction and altering tactile perception. In a cupping context this can create false positives or exaggerate acidity, which is why competition cuppers purge grinders and control thermal load.

• Environmental humidity, which influences static charge, clumping and the aerodynamic behaviour of ground coffee. High humidity reduces static but increases moisture uptake, affecting density and extraction. Low humidity increases static and may skew the proportion of fines in each bowl. Both outcomes change the sensory profile.

• Sensory fatigue, which arises from repeated stimulation of the olfactory and gustatory systems. After several cups, receptor sensitivity decreases, hedonic bias increases and detection thresholds shift. Professionals mitigate this by sequencing samples, controlling pace and using palate resets to maintain calibration. These factors can dramatically alter the outcome of a cupping session. Professionals usually discuss these in environments where sensory precision and repeatability matter. They are often the difference between simply tasting coffee and actually evaluating it.

3. Cupping for Structure Rather Than Notes

Beginners focus on tasting notes. They look for blueberries, citrus, chocolate or florals because these are the easiest parts of the coffee to describe. However, expert cuppers focus on something else entirely: structure. Structure refers to the pattern and behaviour of the coffee, the way all its chemical and tactile components interact across the palate. As a result, it is less about what the coffee tastes like and more about how it behaves.

Structure includes how acidity arrives, how sweetness balances that acidity and how weight and texture move through the mouth. It also describes how the finish resolves over time. At a scientific level, these sensations relate to different organic acids, sugars, lipids and polysaccharides. Each compound influences the speed, intensity and duration of flavour perception. For example, when a cupper describes a long, clean finish, they often respond to low levels of astringent phenolics and a stable distribution of non-volatile compounds that maintain sweetness as the cup cools.

Notes are descriptors. Structure is architecture. Notes point to recognisable flavours. In contrast, structure shows the internal organisation of those flavours. It highlights the transitions from acidity to sweetness to finish. It also shows how texture amplifies or softens certain sensations and how clarity holds as the temperature drops. Therefore, structure offers a more complete and scientific way of understanding what is happening in the cup.

This focus on structure is what allows Brewers Cup competitors to design recipes that express the true character of a coffee. They do not brew to chase a blueberry note. Instead, they build a recipe that highlights the acidity phase, preserves mid-palate sweetness and manages tactile weight. They aim to present a coherent cup from hot to cool. In other words, they brew in a way that reflects the coffee’s chemistry, not just its flavour.

At this stage of cupping, your focus shifts from naming flavours to understanding the forces that create them. You begin to see the cup as a system shaped by chemistry, temperature, structure and extraction behaviour. Consequently, this foundation prepares you for the next part of the journey, where we explore how roasting and processing influence that system.