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A practical specialty coffee guide

Coffee water, clearly explained.

A brewed filter coffee is approximately 98% water. Understanding its mineral composition gives you another way to make specialty coffee more repeatable without turning each brew into a chemistry project.

Start with the largest ingredient

What is coffee water?

Coffee water is simply the water used to brew coffee. It is worth treating as an ingredient with its own mineral composition rather than an invisible background variable. Calcium, magnesium, bicarbonate, sodium, chloride, sulfate, and other dissolved ions can all contribute to how the finished cup is perceived.

Water is not the only variable that matters. Coffee quality, roast, age, grinder, recipe, temperature, and technique remain decisive. But when those inputs are held steady, changing the water can change perceived acidity, sweetness, bitterness, body, and finish.

A coffee water mineral concentrate is one way to make that variable repeatable: begin with low-mineral water, then add a measured mineral profile. It is a workflow tool, not a guarantee that every coffee will taste the same or that one profile will suit every palate.

98%

Why 98% matters

Filter coffee is mostly water, typically around 98% to 99%. That does not mean water always outweighs coffee choice or brewing technique, but it makes water too substantial to treat as an afterthought when consistency matters.

Three measurements, three different jobs

Hardness, alkalinity, and TDS

These terms are related, but none is a complete flavour score. Use them to describe water, not to declare it good or bad in isolation.

Hardness

Mostly the calcium and magnesium in the water.

Hardness describes part of the water’s mineral content, commonly expressed as calcium-carbonate equivalents. The amount and balance of these ions can influence how a coffee presents, but more hardness is not automatically better.

Alkalinity

The water’s capacity to buffer acids.

Bicarbonate is usually the main contributor. Higher alkalinity can soften perceived acidity; very low alkalinity provides less buffering. It is related to pH, but the two measurements are not interchangeable.

TDS

An estimate of all dissolved material, not a recipe.

A handheld TDS meter normally estimates total dissolved solids from conductivity. Two waters can show the same reading while containing different ions, so the number alone cannot predict how they will taste in coffee.

Choose the base water first.

For a mineral recipe

Distilled, demineralised, or high-purity RO water gives a concentrate a predictable starting point. Check the label or measure if needed: “filtered,” “spring,” and “drinking” water may still contain a meaningful mineral load. Starting water does not need to be fashionable; it needs to match the recipe’s assumptions.

Singapore tap water is safe to drink.

PUB states that Singapore’s tap water is suitable for drinking directly from the tap and is within applicable drinking-water regulations and WHO guidelines. Choosing a controlled base for specialty coffee is a flavour and repeatability decision, not a claim that tap water is unsafe.

Read PUB’s water-quality guidance(opens in a new tab)

You can brew coffee with Singapore tap water as supplied. For Bright Bloom’s intended profile, however, adding the full dose to water that already contains minerals makes the result harder to predict. Use the specified low-mineral base when repeatability is the goal.

A controlled, four-step routine

The Bright Bloom workflow

One 120 mL bottle makes approximately 24.7 litres, or about 90 cups, at the recommended 80 ppm profile.

  1. Choose a low-mineral base

    Use distilled, demineralised, or high-purity reverse-osmosis water. Starting close to zero keeps the existing mineral content from obscuring the intended profile.

  2. Shake and measure

    Shake Bright Bloom, choose a 60, 80, 100, or 120 ppm preset, or enter a custom target in the calculator. Measure the matching dose into the base water. Start with 4.85 mL per litre for the recommended 80 ppm profile.

  3. Mix before brewing

    Stir or shake the prepared water until evenly mixed. The selected ppm figure describes nominal added-ion mass from a near-zero base, not a guaranteed TDS-meter reading.

  4. Hold the other variables steady

    Use the same coffee, grind, temperature, ratio, and technique for a useful comparison. Taste first, then decide whether the water suits that coffee and your preferences.

Know what you are adding

The Bright Bloom formula is published.

Every mineral salt, purity specification, and quantity used in the 120 mL concentrate is listed on the product page. Transparency lets you understand the profile and decide whether this approach fits your brewing.

See the full formulation

Common questions

Coffee water FAQ

Can I make good specialty coffee with tap water?

Yes. A mineral concentrate is optional, not a prerequisite for good coffee. If your tap water tastes clean and produces coffee you enjoy, keep using it. Controlled coffee water is most useful when you want a repeatable mineral starting point or wish to compare water profiles deliberately.

Is a particular TDS reading the whole target?

No. Bright Bloom offers nominal 60, 80, 100, and 120 ppm presets plus a custom calculator, but meter conversion, temperature, and the base water can affect a reading. More importantly, TDS does not identify the ions present. Treat it as a useful check, not a complete recipe.

Will one water profile improve every coffee?

Not necessarily. Bright Bloom is designed as a balanced, all-in-one foundation with light and light-medium roasts in mind, but taste is personal and coffees vary. Compare it with a control brew and judge the cup rather than the claim.

Comparing coffee water products in Singapore?

See how powder sticks, single-profile liquid, and blendable concentrates differ in everyday use.

Compare the formats