Barista Terminology | Episode 7: Water & Temperature Control
We’re excited to continue our “Barista Terminology” series on QahwaWorld.com—your guide to mastering essential coffee concepts. In Episode 7, we focus on water and temperature control, two often-overlooked factors that greatly impact flavor, clarity, and consistency. From water quality and filtration to ideal brewing temperatures, this episode covers the key terms every barista must know to brew with precision.
Water is the most overlooked yet most influential ingredient in coffee — it makes up over 98% of the final cup. Along with temperature, water quality and composition play a major role in extraction, flavor clarity, and consistency. In this episode, we explore the critical terms related to water and temperature control that every barista must understand.
1. Brew Water
The water used to brew coffee. It should be clean, odorless, and within specific mineral content guidelines to avoid negatively affecting flavor.
2. Water Quality
Refers to the chemical composition of water, including minerals, pH, and contaminants. Poor water quality can ruin coffee flavor, damage equipment, and affect consistency.
3. Hardness
The amount of calcium and magnesium in water. Moderate hardness helps extraction, but excessive hardness causes scale build-up and alters taste.
4. Total Dissolved Solids (TDS)
Measures how much material (minerals, salts, metals) is dissolved in water. Ideal brew water typically has TDS between 75–150 parts per million (ppm).
5. Alkalinity
The ability of water to resist changes in pH. Alkalinity affects the balance of acidity in the cup. Too high = flat taste, too low = sourness.
6. pH Level
A measure of how acidic or basic the water is. Ideal brewing water has a pH around 7 (neutral), slightly on the acidic side.
7. Chlorine
Often found in tap water, chlorine negatively affects flavor and should be removed via filtration or charcoal.
8. Water Filtration
The process of purifying water using filters to remove unwanted substances. Essential for consistent taste and equipment longevity.
9. Reverse Osmosis (RO)
A water purification method that removes nearly all minerals and contaminants. Often used with remineralization to restore optimal composition for brewing.
10. Water Temperature
The temperature of water during brewing — a key variable. Most coffee is brewed between 90°C and 96°C for optimal extraction.
11. Temperature Stability
The ability to maintain a consistent brew temperature throughout extraction. Fluctuations can lead to poor flavor development.
12. Cool Water / Underheated Water
Water below optimal temperature causes under-extraction, resulting in weak, sour coffee with muted flavor notes.
13. Overheated Water
Water above 96°C can over-extract bitter compounds and degrade flavor, especially in lighter roasts.
14. Boiler
The internal component in coffee machines that heats water. High-end machines often have multiple boilers to separate brew and steam temperature control.
15. PID Controller
A digital system in advanced machines that precisely regulates water temperature, helping maintain thermal stability and consistency.
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