Brewing Coffee, Approximately 98% of each cup of coffee you brew is water, but it’s seldom just plain water. The composition of your water varies based on your location, containing different levels of minerals and organic compounds.
Key elements like calcium, magnesium, and carbonates influence how coffee extracts and ultimately taste. This means that even the highest-quality coffee can be hindered from reaching its full flavor potential if your water isn’t ideal. To delve deeper into how water quality and temperature impact coffee, I consulted experts Jennifer Yeatts and Maxwell Colonna-Dashwood. Continue reading to discover their insights.
Temperature Tips for Perfect Brewing Coffee
Before delving into the specifics of water quality and mineral content, let’s first address water temperature. Jennifer Yeatts, the Director of Coffee at Higher Grounds Trading Co., a B-Corp-certified roaster based in Michigan, emphasizes the importance of temperature.
She advises, “To achieve optimal flavor extraction, your brewing water should be kept between 90°C and 96°C (195°F to 205°F). Deviating from this range can lead to inadequate extraction and diminished flavor.” Jennifer explains that during brewing, water extracts volatile compounds responsible for coffee’s aroma and taste. If the temperature is too high, these compounds are released too rapidly, complicating the extraction process.
This rapid release can lead to a higher concentration of bitter or sour compounds in the coffee, especially in darker roasts, which are more soluble. Consequently, lower temperatures can help prevent over-extraction and mitigate excessive bitterness or sourness.
Jennifer also mentions that Higher Grounds includes this topic in their barista training curriculum. To manage brewing temperatures effectively, she recommends using temperature-controlled kettles and gooseneck kettles, the latter of which provide better control over the flow rate and can enhance overall precision in brewing.
Water Hardness and Its Effect on Water Quality
Maxwell Colonna-Dashwood, co-owner and Managing Director of Colonna Coffee in Bath, UK, is also the founder of Peak Water, a water filtration system, and the co-author of Water For Coffee. He clarifies the distinction between water quality and hardness.
Different regions and countries treat water in various ways,” Maxwell notes. “While municipal systems ensure water is safe to drink, it doesn’t always meet high-quality standards.” For optimal coffee brewing, water should be clean, free of visible contaminants, and odorless, though its hardness and quality can differ depending on location.
“High-quality drinking water isn’t always ideal for coffee,” Maxwell explains. “Brands like Evian, although high-quality, have relatively high hardness.” Water hardness is a crucial factor in the coffee industry for evaluating carbon content and its effects on equipment. Maxwell elaborates that hardness, measured as total dissolved solids (TDS), reflects the concentration of minerals and ions in water.
TDS meters gauge these microscopic elements in parts per million (ppm), which represents milligrams per liter. There are two types of hardness to consider: total hardness, which measures calcium and magnesium levels, and carbonate hardness, which indicates the amount of carbonates and bicarbonates present.
Maxwell describes carbonate hardness as “temporary hardness” because it involves the formation of calcium bicarbonate, which can result in limescale buildup. Limescale, a chalky residue, often accumulates inside brewing devices and coffee machines, leading to potential damage.
For brewing purposes, the Specialty Coffee Association suggests water with a total hardness between 50 and 175 ppm and a carbonate hardness ranging from 40 to 75 ppm.“You can also encounter water with low carbon content but high TDS, which won’t produce limescale,” Maxwell adds.
How Carbonates Affect Your Water
During his routine at the 2014 World Barista Championship, Maxwell emphasized the critical role of mineral content in coffee extraction. He brewed three variations of a washed Ethiopian filter coffee, each with differing levels of magnesium, calcium, and carbonates.
Although heating or boiling water can alter its magnesium, calcium, and carbonate concentrations, these changes are typically minor and have minimal impact on coffee flavor. Maxwell’s WBC presentation underscored the significance of bicarbonates in flavor development.
Bicarbonates are produced when carbon dioxide reacts with water to form carbonic acid, which then interacts with carbonates to generate bicarbonates.
“Bicarbonates act as ‘buffers,’” Maxwell explains. “A higher concentration of bicarbonates means greater buffering of acidity, reducing its impact.”
While the Specialty Coffee Association suggests maintaining a pH range between 6 and 8, Maxwell notes that pH is not a direct measure of a water’s buffering capacity, also known as alkalinity. pH levels reveal whether water is acidic or alkaline, but Maxwell advises that pH is not a straightforward indicator of how coffee flavor will be influenced. Instead, he suggests that buffering capacity is a more accurate measure of potential flavor impact.
Effects on extraction
Magnesium, calcium, and carbonates each affect how flavor compounds are extracted from ground coffee, but they do so in distinct ways. Maxwell highlights that the levels of carbonates and bicarbonates in water are key indicators of how flavor will be impacted.
“Testing the alkalinity of the water provides insights into its potential influence on coffee flavor,” he explains. He also notes that water hardness plays a role in determining coffee’s flavor and texture.
“With soft water, coffee tends to have a lighter body and higher acidity, which can sometimes come across as sour,” Maxwell observes. “On the other hand, hard water can make coffee taste muddier, thicker, and chalky, leading to a flat flavor.”
Adjusting water quality based on these factors can significantly enhance the final cup. Research from Zurich University of Applied Sciences found that Brazilian and Colombian coffees, in particular, scored higher when brewed with water of low to medium mineral content.
Testing and filtration systems
Understanding water hardness and mineral composition is crucial for consistently brewing great-tasting coffee. However, managing and adjusting these factors is just as essential. The initial step often involves measuring the alkalinity and hardness of your brewing water.
Maxwell suggests, “A simple method is to use aquarium or pond test strips, which measure alkalinity in KH (carbonate hardness).” Jennifer adds, “Using TDS meters and refractometers can provide insights into water quality and its impact on your coffee.”
For a comprehensive analysis of your water’s composition, Maxwell recommends a full lab test, though local water authorities might also provide information on hardness and mineral content. Once you know your water’s hardness, you can adjust its mineral levels to optimal ranges. “If you have soft water, using a carbon stick can help remove impurities,” Maxwell advises. However, while carbon sticks can purify tap water to some extent, they do not alter its mineral content.
For those with hard water, Maxwell suggests an ion exchange filter. “This filter uses resin beads to change the mineral composition of the water.” As water flows through these resin beads, minerals are either added or removed based on the water’s hardness.
Maxwell further notes, “In regions where water hardness exceeds 550 ppm, reverse osmosis systems are recommended. These systems effectively demineralize water using high-pressure semipermeable membranes.” Reverse osmosis filters out minerals by forcing water through a membrane, adjusting the mineral content to desired levels.
Jennifer also points out that there are various products available to adjust water mineral content. “From commercial filtration systems to Third Wave Water mineral packets, you have many options to manage water quality effectively.”
Enhancing Your Brewing Water: Tips and Techniques
Improving your water quality can be challenging, but Maxwell emphasizes the importance of understanding your local water source. “Consumers often have to work with the quality of water available to them, so gaining insight into your local tap water is crucial,” he explains. “We developed Peak Water because we observed that coffee shop filtration systems were tailored to local water quality, achieving the ideal hardness levels.”
“Peak Water enables home users to replicate the effective filtration systems used in coffee shops.” For coffee shop owners, Jennifer stresses the importance of treating water filtration as a critical investment. “Many commercial coffee equipment warranties require the installation of water filtration systems,” she notes. “Failure to use such systems may void the warranty.”
Optimal water hardness can differ depending on whether you are brewing filter coffee or espresso. Home users might find it beneficial to adjust their water’s mineral content based on their brewing methods. “Coffee typically has a pH around 5,” Maxwell says. “Adding a small amount of baking soda to coffee with bright, fruity flavors can soften its acidity.”
He also notes that softer water is generally better for filter coffee, while espresso benefits from more alkaline water. “For filter coffee, softer water (about 100 ppm) with alkaline levels between 30 and 80 is often preferred,” Maxwell explains. “Conversely, for espresso, more alkaline water can help balance the acidity of the stronger coffee.”
Maxwell also advises considering roast profiles. “For darker roasts, softer water is recommended, while lighter roasts may benefit from harder water to enhance flavor clarity.”
Although water is crucial to your coffee brewing process, its significance is often underestimated.
Regardless of how well your coffee is brewed, the quality of your water will inevitably impact its flavor. The first step is to ensure that the water’s quality and hardness are suited for brewing coffee, and then adjust as needed based on your preferences.