How Water Quality Affects the Taste of Your Tea and Coffee

The Specialty Coffee Association recommends water with a TDS of 75 to 250 mg/L and a pH of 6 to 8 for optimal extraction. Hard water causes scale and produces flat, bitter flavours; soft water over-extracts and turns astringent.

Kenya's Double Advantage, and the Water Problem

Kenya is home to some of the world's most celebrated teas, Kenyan orthodox from Nandi Hills, Kericho and Limuru, and a growing specialty coffee scene from Nyeri, Kiambu and Mount Elgon estates. The complexity of these flavours, however, can be dramatically suppressed by the water used to brew them. In areas with high mineral content or chlorinated municipal water, the full character of a premium Kenyan tea or single-origin espresso simply does not come through.

The Science of Extraction

Both tea and coffee extraction are chemical processes where water molecules carry flavour compounds, oils and aromatic molecules out of the leaf or ground bean. The mineral content and pH of the water directly affect which compounds are extracted and in what proportion:

• Magnesium ions (Mg²⁺): Selectively extract fruity acids and aromatic compounds, beneficial in moderate amounts.
• Calcium ions (Ca²⁺): Bind with certain aromatic acids, muting floral and citrus notes, problematic at high concentrations (hard water).
• Chlorine / chloramine: React with organic compounds in tea and coffee to produce harsh, medicinal off-flavours.
• Bicarbonate (alkalinity): Neutralises acids in coffee, reducing perceived brightness and complexity.

What Nairobi's Water Does to Your Brew

Nairobi municipal water has a TDS averaging 180–280 mg/L and is chlorinated to a residual of 0.2–0.5 mg/L. The hardness (primarily calcium carbonate) tends toward the medium-high range. This means:

• Chlorine is the most immediate problem, it suppresses delicate floral aromas in tea and produces harsh notes in coffee.
• Calcium hardness in the high range flattens the complexity of single-origin coffees, particularly washed Kenyans.
• Hard water accelerates scale buildup in kettles and espresso machines, reducing their lifespan and further degrading water quality at the heating element.

The Ideal Water Profile for Kenyan Tea and Coffee

How Filtered Water Transforms Your Cup

A multi-stage RO system with a mineralisation stage produces water in the ideal TDS range (50–150 mg/L post-remineralisation), removes all detectable chlorine, and reduces hardness to a level that allows full flavour expression. Professional baristas in Nairobi's specialty cafes have adopted RO-filtered water precisely because it produces consistent, balanced extraction regardless of what the municipal supply delivers that day.

Brew better with better water

iClear's mineralisation stage produces water at the ideal TDS and pH for Kenyan tea and specialty coffee. Find out more.