• The SCA has set parameters for the best water to use for coffee, including total hardness of 50-110 ppm
• Local water supplies in many countries can adversely affect coffee’s characteristics due to high or low mineral content
• BWT water+more solutions create the best water for cupping and can help reveal new flavours and aromas in coffees

THE CUPPING table represents a critical moment for coffee producers. It is the point at which all the product of their hard work –  all the nurturing, harvesting, and processing of their coffees – is put in front of buyers, tasted, and a price negotiated.

That price invariably stems from the quality of the coffee and its inherent characteristics as experienced on the cupping table. A Geisha coffee may command a higher than average market price, but if it doesn’t live up to expectations during cupping, it is unlikely to generate the anticipated returns.

However, one of the most influential factors during a cupping is one largely out of the producer’s control: water quality. Making up more than 98% of the final brew, water can influence everything from aroma to mouthfeel.

Bad-quality water can make coffee taste over or under-extracted, imbalanced, and bitter. Its magnesium and calcium content can change the coffee’s sweetness and body. And low alkaline water can make it taste vinegary and sour.

To reduce inconsistencies and create an industry standard, the Specialty Coffee Association (SCA) published a set of benchmarks for the best water to use in coffee, including the following:

• Total hardness of 50-110 ppm CaCO3 (2,9-6,2°dGh)
• Carbonate hardness of 40-75 ppm CaCO3 (2,2-4,2°dKh)
• pH of 6-8

The theory is that if the properties of the water fall outside these parameters, it will adversely affect the coffee’s characteristics. When this happens, it effectively wipes value off the final price of the coffee – a desperately sad outcome considering all the work that goes into producing it.

“If you brew low, medium, and high-quality coffees with bad quality water that’s full of chlorine and has low mineral content, the perceived quality of the coffees will be a lot closer to one another,” explains Antoine Communaudat, who works as export area manager at BWT water+more, a water treatment company. “But if the water quality is good, you give more expression to the differences between them.”

The soft water problem

Water quality differs from one place to the next and regional differences within the same city can even occur. The north of London, for example, has marginally better water quality than the south.

A common issue across a number of countries, including the UK, Australia, Canada and the US, is the presence of “hard water”.

The hardness of water is determined chiefly by the amount of calcium and magnesium present. The higher the percentage of these minerals, the harder it is. Hard water is the main culprit for damaging equipment such as espresso machines as it leaves behind deposits of limescale. However, it can also affect the coffee’s taste. High calcium content can cause over-extraction and bring out bitterness, for example.

Conversely, many regions across South America and Central America suffer from soft water – or water with low mineral content. This is also bad news for coffee as soft water typically struggles to extract the full spectrum of flavour compounds, leaving an under-extracted, “flat” tasting cup.

“With soft water, you don’t have the limescale problem,” Antoine says, “but you’ll need to increase the mineral content to get the best extraction.”

As mentioned, this can be a problem for coffee producers looking to obtain the highest prices for their coffees. But it can also affect consumption.

“Until a few years ago, people in Latin America were producing the best coffees in the world, but exporting the best part of their harvest and drinking the leftovers,” Antoine explains. “Now, the trend is that those countries are increasingly consuming the best part of their coffees. But the market is still not as developed as other countries. Coffee equipment is being upgraded, but there is still a room for improvement as far as water quality is concerned.”

In short, if high-quality water isn’t being used to extract coffee, it can make it difficult to convince consumers to pay higher prices per cup. The subtle differences between coffees become blurred and cheaper options become more attractive.

Towards a better brew

Consistently using water for coffee that meets the SCA’s parameters is difficult. Not only does quality vary considerably from region to region, but buying bottle after bottle of mineral water can be both environmentally and economically unsustainable. It can also be unsuitable both for coffees and coffee machines, depending on the mineral content.

However, for coffee producers the benefits of good-quality water for cupping are clear. Even one or two additional points on the SCA’s protocol can mean significantly more money, while Antoine explains it equips them with far greater negotiating powers.

“At BWT water+more, we ensure, through our water optimisation solutions, that every coffee can develop its full quality of aroma and flavours, thus allowing farmers to cup in perfect conditions,” he says. “By doing so, they can achieve better perceived value for their coffees.”

Over the last few years, BWT water+more built this aspect into their business. Having focused on the relationship between water and coffee since 2006 (first on how it affects equipment, then on how it affects taste) this is considered the next logical step in the journey. 

They have already started working with coffee producers and cooperatives in Honduras, Colombia, and Kenya, and aim to expand their water treatment solutions to cupping labs across the globe. Their water filtration systems help to produce the best quality water for bringing out all the characteristics of the coffee in line with SCA benchmarks.

“We are at the beginning stage of this whole process,” Antoine says. “We don’t expect to do lots of business. But we want to educate people and help the market grow. 2023 is the year in which we hope to educate people about the importance of good-water quality, how you measure it, and what you need to do.”

BWT water+more is a sponsor at this year’s Producer & Roaster Forum in El Salvador.

Following a successful event in Medellín, which fostered around $10.5 million in sales, Producer & Roaster Forum will return to San Salvador between March 16 and 17, 2023.

The two-day event brings together thousands of coffee professionals and industry leaders from around the world, offering a unique opportunity to network, participate in workshops, listen to talks, and join roundtable discussions.

Don’t miss out on the world’s largest producer-focused coffee event. Register for tickets today.