As temperatures rise across the UK, hospitality operators face challenges that extend beyond keeping customers cool. Hot, dry conditions can alter the sources and mineral composition of tap water, with implications for beverage quality, equipment efficiency and operational consistency.

Emma Field, coffee expert at Brita Professional, examines how heatwaves can affect the water used to prepare tea and coffee, and explains why effective water management should be an essential part of maintaining quality and protecting equipment.

As the UK experiences another spell of extreme heat, much of the conversation has understandably focused on the immediate effects of rising temperatures, from health concerns and transport disruption to pressure on the national grid. However, one less obvious consideration is the impact heatwaves can have on water quality and, in turn, on coffee and tea. 

With water making up approximately 98% of a cup of tea or coffee, changes in its composition can affect everything from taste and consistency to the performance of beverage equipment. For hospitality businesses serving drinks at scale, understanding how extreme heat can affect water quality is an important part of maintaining a consistent serve. 

The chemistry behind a consistent cup 

The characteristics of tap water can vary considerably across the UK, depending on where the water is sourced and the geology of the area it passes through. As water moves through rocks and soil, it naturally picks up minerals, which is why areas such as Brighton and Norwich can experience much harder water than cities such as Cardiff and Edinburgh. During periods of hot, dry weather, water companies may also use different or supplementary sources to maintain supply, potentially introducing further variation. 

For tea and coffee, these differences matter. Dissolved minerals such as calcium and magnesium can influence how flavour compounds are extracted from coffee, while the composition of water can also affect the extraction, aroma and sensory qualities of tea. The result is that the same beans or tea leaves, prepared to the same recipe, may produce a noticeably different cup if the incoming water changes. 

The impact on coffee machines 

As well as taste, changing mineral content affects the equipment cafés rely on. When hard, unfiltered water is heated, limescale can form, which builds up inside equipment. Even a relatively small amount can make a difference: just 1mm of limescale build-up can mean 7% more energy is needed to heat water. Left unmanaged, scale can also put additional strain on components, compromising machine performance and increasing maintenance requirements over time. 

And the impact of getting water management right goes beyond maintenance alone. Brita Professional's latest research found that 82% of hospitality businesses are losing valuable service time to water and limescale issues, while more than half say a single episode of unplanned downtime can damage their long-term reputation. 

Managing changing water conditions 

For coffee teams, regular tasting and close attention to extraction can provide an early indication that something has changed.

Overly hard water can produce dull, heavy or chalky coffee, while water that is too soft can contribute to over-extraction and excessive bitterness. Changes in taste can therefore be an important prompt to check incoming water conditions, as well as machine set-up and filtration. 

Smart water filtration can help balance mineral content, protect espresso machines from limescale and support consistent flavour and aroma. It can also give operators greater control when incoming water conditions change, helping them maintain a more stable brewing environment across different seasons and locations.  

But effective water management goes beyond filtration alone. BRITA’s iQ range provides real-time insights into water consumption and remaining filter life, helping operators understand when a replacement is due and plan maintenance accordingly. 

The company's iQ can also automatically adjust filtration settings when the composition of incoming water changes. This can reduce the risk of limescale-related breakdowns and unnecessary downtime, while making filter management simpler – particularly for operators managing equipment across multiple sites.  

Making every drop count

While hospitality businesses can’t control the weather, they can take steps to manage what happens next. With the right filtration in place, hospitality businesses can help protect the consistency of every serve and the equipment behind it. 

Water is, after all, a fundamental part of every serve. When so much care goes into selecting the bean, perfecting the roast and investing in the right machine, the water running through it should never be an afterthought.