FINAL TOUCH 💧

Meet Lab Coffee
May 28
3 min read

WATER CHEMISTRY – PART 3: The Final Touch for Brewing

In our previous blog post on Water Chemistry – Part 3, we discussed how existing water sources often need improvement for coffee to extract properly and achieve maximum flavor potential. We emphasized that using tap water directly for coffee brewing is far from ideal and can lead to unsatisfactory results.

It is essential to soften water to specific levels before using it. Common methods for softening include reverse osmosis (RO) and ion exchange, each with its own advantages and drawbacks.

Reverse osmosis uses pressure to push water through a membrane, removing ions and thus reducing hardness. However, RO also removes beneficial minerals that influence coffee flavor, which may result in a flat cup profile.

Ion exchange replaces calcium and magnesium ions (which cause hardness) with sodium or hydrogen ions. Using ion exchange resins, this method softens the water while maintaining essential mineral content, making it more precise and flavor-friendly than RO.

Still, both systems provide softened water without controlled delivery of specific ions. Even if some RO systems reintroduce ions like Mg²⁺ and Ca²⁺, the concentrations are often too low to optimize coffee extraction. Additionally, such filtration systems are not always accessible or affordable. That’s why alternative solutions are needed.

Inspired by this, we at Meet Lab Coffee are proud to introduce our “FINAL TOUCH” product—a finishing step designed for professional brewers seeking precision and flavor in every cup. Here’s what makes it special.

Why Mineral Ions Matter

Optimal coffee extraction requires mineral ions that can penetrate the cellulose structure of coffee cells and bind with soluble compounds. According to the SCA and leading coffee scientists, magnesium (Mg²⁺), calcium (Ca²⁺), sodium (Na⁺), and potassium (K⁺) ions enhance flavor by aiding this process.

To improve extraction, salts like MgCl₂ and CaCl₂ can be added to increase hardness. However, excessive use can overwhelm flavor and introduce unwanted bitterness. Therefore, balance is key. Calcium is naturally abundant in water—even after filtration—compared to other salts.

These salts form hydrates in water:

CaCl₂ + 6H₂O → CaCl₂·6H₂O
MgSO₄ + 7H₂O → MgSO₄·7H₂O

These hydrates are the sources of free Ca²⁺ and Mg²⁺ ions, aiding extraction but not contributing to softening. Excessively hard water can decrease extraction efficiency due to “soapy” effects—again, balance is essential.

Bicarbonate salts like NaHCO₃ and KHCO₃ increase alkalinity and raise pH—helping to neutralize coffee’s natural acidity and creating a smoother flavor.As a magnesium source, both MgCl₂ and MgSO₄ are viable, but MgCl₂ is preferred due to its higher effectiveness and lower bitterness.

MgCl₂ reduces surface tension, improving water’s wetting properties, which enhances flow and dissolving power. That’s why it’s the choice in our FINAL TOUCH product.

Choosing the Right Water for Origin

Water preferences vary by coffee origin:

South American beans often pair better with harder water.
African beans respond better to softer, more bicarbonate-rich water.

Ideally, origin-specific water formulas should be based on detailed mineral analysis of the soil and beans—but in practice, skilled baristas can rely on sensory evaluation to guide brewing recipes.

As we’ve mentioned in earlier blogs, sensory panels and expert tastings are now increasingly valued alongside analytical and instrumental testing in the coffee science world.

FINAL TOUCH: The Solution for Every Brewer

Whether you’re a barista aiming for perfection, a coffee shop unable to afford expensive filtration systems, or a home brewer seeking café-quality coffee, FINAL TOUCH is your last step toward an exceptional cup.