Does Softer Water Always Make Better Coffee?

If hard water causes limescale, it may seem logical to assume that the softer the water, the better it must be for a café. However, when it comes to coffee and other beverages, the relationship between water and flavour is more complicated.

Water hardness is mainly influenced by dissolved calcium and magnesium. These minerals can contribute to limescale formation when hard water is heated, which is one reason hardness is an important consideration for commercial coffee equipment.

But these same minerals can also interact with compounds during coffee extraction.

Researchers from the University of Bath studied the role of dissolved ions in coffee extraction and found that calcium and magnesium interact with different coffee compounds. Their research demonstrates that the mineral composition of brewing water can influence extraction behaviour.

Another peer-reviewed study from Kyungpook National University's School of Food Science & Biotechnology compared coffee brewed with distilled, medium-hardness and high-hardness water. Researchers found differences in several extracted compounds depending on water hardness. Their sensory testing also showed that preferences were not simply determined by whether the water was harder or softer.

For F&B operators, this provides an important lesson: water treatment should not simply be about making TDS or hardness as low as possible.

A café needs to consider several objectives at the same time. The water needs to work with the equipment, excessive scale should be controlled, and the mineral composition should be appropriate for the beverage being prepared.

Therefore, instead of asking, “How can we remove all the minerals?”, a more useful question may be: “What water quality is suitable for our beverage and our equipment?”

Testing the incoming water and comparing the results with the equipment manufacturer's recommended water specifications can provide a much better starting point for choosing an appropriate F&B water-treatment system. This content was AI-generated, please review yourself.

References

1. Hendon, C.H., Colonna-Dashwood, L. & Colonna-Dashwood, M. (2014). The Role of Dissolved Cations in Coffee Extraction. Journal of Agricultural and Food Chemistry, 62(21), 4947–4950. University of Bath.
https://researchportal.bath.ac.uk/en/publications/the-role-of-dissolved-cations-in-coffee-extraction/

2. Yoo, I.K., Jang, D.H., Kwon, W.J., Lee, K.H. & Lim, J. (2020). Effect of Water Hardness on Coffee Composition and Coffee Preference by University Students. Korean Journal of Food Science and Technology, 52(5), 435–440. Kyungpook National University.
https://research.knu.ac.kr/en/publications/effect-of-water-hardness-on-coffee-composition-and-coffee-prefere/

3. Drinking Water Inspectorate (UK). Water Hardness / Hard Water.
https://www.dwi.gov.uk/consumers/learn-more-about-your-water/water-hardness-hard-water/