Water Quality for Coffee

The Forgotten Ingredient

Your cup of coffee is approximately 98% water. Yet water quality is the most overlooked factor in coffee preparation. The mineral composition of your water dramatically affects extraction efficiency, flavor development, and even the longevity of your equipment.

What Makes Good Coffee Water?

The SCA recommends these specifications:

• Total Dissolved Solids (TDS): 75-250 ppm (ideal: 150 ppm)
• Calcium hardness: 50-175 ppm (ideal: 68 ppm)
• pH: 6.5-7.5 (neutral)
• Chlorine: 0 ppm
• Sodium: below 10 ppm

How Minerals Affect Flavor

• Too soft (low minerals): under-extracts; coffee tastes flat, sour, and empty
• Too hard (high minerals): over-extracts; coffee tastes bitter, chalky, and dull
• Magnesium helps extract fruity, bright flavors
• Calcium enhances body and heavier notes
• Bicarbonates buffer acidity — too much kills brightness

Improving Your Water

Filtration

A basic activated carbon filter (like Brita) removes chlorine and improves taste but does not significantly change mineral content. For espresso machines, consider a BWT or specialty water filter designed for coffee.

Water Recipes

Enthusiasts create custom water using distilled water plus precise mineral additions. Popular recipes include:

• Third Wave Water — mineral packets for distilled water
• Barista Hustle recipes — DIY mineral concentrates

Protecting Your Equipment

Hard water causes limescale buildup in boilers and heating elements, reducing efficiency and eventually causing failure. Regular descaling or using properly filtered water extends machine life significantly.

At Röstschmiede, we calibrate our brewing equipment for our local water and recommend our customers do the same. Even a simple carbon filter can make a noticeable difference in your daily cup.