+44 (0)20 7202 2620

What effect does water mineral content have on coffee?

Here at DR Wakefield, we know that the art of coffee making is a delicate science and that is why we ensure we source all our green coffee beans from the very best growers around the world, that have given the same attention and care to their work as we do.

There are many aspects that count towards the quality and taste of a cup of coffee, such as the region a bean was grown in and how it is roasted.

However, according to a new piece of research, the mineral content of the water used to make the beverage is a vital contributor to both its quality and taste.

This isn't just an important factor when a barista is serving a drink in a coffee shop, but also something to bear in mind during the initial roasting process when the beans are being washed and selected for use.

The research

Christopher Hendon, a PhD student in theoretical and computational chemistry at the University of Bath, embarked on an investigation with his friend Maxwell Colonna-Dashwood – who owns a coffee shop in the city – to discover how both hard and soft water affected a cup of coffee.

The pair set out on this quest after Mr Hendon overheard two baristas having a frustrated conversation about why two cups of coffee that are seemingly the same can taste completely different on two days.

And eureka! The scientist identified that water – arguably one of the components of coffee making that we take for granted the most – was to blame.

Using advanced chemistry techniques, the coffee fanatics carried out a series of tests to find out how mineral composition could contribute to the flavour of a roast.

It was found that the effectiveness of the process of extracting flavour from a bean was greatly improved if the water used contained high levels of magnesium ion.

Despite many bottled mineral waters being rich in sodium, water containing high levels of this substance was not found to be beneficial to the taste of coffee, with similar results being discovered for water high in bicarbonate.

Mr Hendon said: "Hard water is generally considered to be bad for coffee, but we found it was the type of hardness that mattered. While high bicarbonate levels are bad, high magnesium ion levels increase the extraction of coffee into water and improve the taste."

The researchers acknowledged that choosing a water source can prove to be a challenge when it comes to making coffee, as the mineral composition of tap water can vary between regions and due to rain levels, and – as the investigators found – bottled water can be high in sodium, which can also affect taste.

Why do minerals matter?

Mr Hendon explained: "Coffee beans contain hundreds of chemicals – the precise composition depends on the type of beans and how it is roasted.

"The flavour of the resulting coffee is determined by how much of these chemicals are extracted by the water, which is influenced by roast profile, grind, temperature, pressure and brew time."

Additionally, the composition of the water used during the roasting process was found to be key in determining how much sugar, starch, base flavours and acid was extracted from a particular batch of beans.

What's next for these coffee experimentalists?

In addition to carrying out fascinating roasting experiments with coffee beans, Mr Hendon and Mr Colonna-Dashwood are planning to release a book detailing their thoughts on the art and science of coffee making.

Later this month, the pair will also be attending the exciting World Barista Championships at the 2014 World of Coffee Festival – which begins on June 9th – in Rimini in Italy, where we at DR Wakefield will be exhibiting too!

Mr Colonna-Dashwood will represent the UK in the challenge, which involves participants being required to prepare four espressos, cappuccinos and authentic signature drinks in just 15 minutes. They will then face a judging panel, being marked on their their skill, creativity, cleanliness and presentation.

He won the UK Barista Championship back in April, so we're certainly looking forward to catching a glimpse of his talents in Rimini!