Water Quality: The Forgotten Ingredient in Great Coffee

You’ve invested in specialty coffee beans, dialed in your grind size, perfected your brewing technique—but something still tastes off. Before you blame the beans or your brewing method, consider this: water makes up 98% of your finished cup. That means the quality of your water has a massive impact on flavor, extraction, and overall coffee experience. Great beans can absolutely taste bad when brewed with poor water. It’s the most overlooked factor in home brewing, yet it’s one of the easiest to fix once you understand the science behind it. Let’s dive into why water quality matters and how you can optimize it for the best possible cup of specialty coffee.

Common water issues

The Science of Water and Coffee

Water isn’t just a neutral carrier for coffee flavor—it’s an active participant in extraction. The minerals dissolved in your water determine how efficiently flavor compounds are pulled from your coffee grounds during brewing. Calcium and magnesium, in particular, play crucial roles in extracting different flavor notes. Calcium enhances body and sweetness, while magnesium pulls out brighter, more complex flavors.

pH levels also matter. Coffee brews best with slightly neutral to slightly acidic water (pH 6.5–7.5). Water that’s too alkaline can mute acidity and create flat, dull flavors. Water that’s too acidic can make coffee taste sour or overly sharp.

Total dissolved solids (TDS) refers to the concentration of minerals in your water, measured in parts per million (ppm). Too few minerals (like in distilled water) means weak extraction and lifeless coffee. Too many minerals can lead to over-extraction, bitterness, and mineral buildup in your equipment. The goal is balance—enough minerals to extract flavor, but not so many that they overwhelm or distort it.

Interestingly, distilled water isn’t the answer. While it’s pure, it lacks the minerals needed for proper extraction. Coffee brewed with distilled water often tastes flat, thin, and underwhelming—proof that minerals are essential for unlocking the full potential of your specialty coffee beans.

Ideal Water Composition for Coffee

Chemistry ranges for ideal water for coffee brewing.

The Specialty Coffee Association (SCA) has established water quality standards to help roasters and home brewers achieve optimal extraction. According to the SCA, ideal brewing water should have a TDS between 75–250 ppm, with a target around 150 ppm. This range provides enough mineral content for balanced extraction without overwhelming the coffee.

Calcium and magnesium are the key players. Calcium contributes to body and mouthfeel, helping create a fuller, rounder cup. Magnesium is responsible for extracting the bright, fruity, and complex flavors that make specialty coffee so exciting. A good balance of both minerals ensures you’re getting the full spectrum of flavors from your beans.

Alkalinity, or buffering capacity, refers to the water’s ability to neutralize acids. Moderate alkalinity (around 40 ppm) helps balance the natural acidity of coffee, preventing it from tasting too sharp or sour. Too much alkalinity, however, can flatten the coffee’s brightness and make it taste dull.

For home brewers, here are the target ranges to aim for: - TDS: 75–250 ppm (ideal: 150 ppm) - Calcium: 17–85 ppm - Magnesium: 5–30 ppm - Alkalinity: 40–70 ppm - pH: 6.5–7.5

Understanding these numbers helps you diagnose water issues and make informed decisions about filtration and treatment.

Common Water Problems and Solutions

Hard water is one of the most common issues for coffee brewers. High mineral content (especially calcium and magnesium) can lead to over-extraction, resulting in bitter, harsh flavors. Hard water also causes mineral buildup (scale) in kettles, coffee makers, and espresso machines, which can damage equipment over time and affect brewing temperature consistency.

Soft water, on the other hand, lacks sufficient minerals for proper extraction. Coffee brewed with soft water often tastes flat, weak, and one-dimensional. You’re missing out on the vibrant, complex flavors that make specialty coffee worth drinking.

Chlorine and chemical tastes are another problem, especially with municipal tap water. Chlorine is added to kill bacteria, but it can impart unpleasant flavors and aromas to your coffee. Even small amounts can distort delicate tasting notes.

Simple home testing methods can help you identify your water’s composition. TDS meters are inexpensive (under $20) and give you a quick reading of total dissolved solids. For more detailed analysis, water testing kits (available online or at hardware stores) can measure hardness, pH, alkalinity, and chlorine levels. Many municipal water providers also publish annual water quality reports online, which can give you a baseline understanding of your tap water.

Ways to fix water issues at home.

Filtration options range from simple to sophisticated:

• Carbon filters (like Brita or PUR pitchers) remove chlorine and improve taste but don’t adjust mineral content significantly. Cost: $20–$40 for the pitcher, plus ongoing filter replacements.

• Reverse osmosis (RO) systems remove nearly all minerals and contaminants, producing very pure water. You’ll need to remineralize RO water for coffee brewing. Cost: $150–$500 for under-sink systems. -

• Water softeners reduce hardness but may add sodium, which isn’t ideal for coffee. Cost varies widely.

• Third Wave Water or similar products are pre-measured mineral packets you add to distilled or RO water to create ideal brewing water. Cost: ~$15 for a pack that makes 5 gallons.

DIY Water Improvement Strategies

Carbon filtration is the easiest first step for most home brewers. A simple carbon filter pitcher or faucet attachment will remove chlorine, improve taste, and reduce some contaminants without drastically altering mineral content. If your tap water is already in a decent TDS range (75–250 ppm), carbon filtration alone might be all you need.

Water softening can help if you have very hard water, but be cautious. Traditional ion-exchange softeners replace calcium and magnesium with sodium, which isn’t ideal for coffee flavor or equipment. If you go this route, consider a bypass or blending softened water with unsoftened water to maintain some mineral content.

Bottled water is a convenient option if your tap water is problematic. Look for spring water with a TDS between 75–250 ppm. Check the label or the brand’s website for mineral content. Avoid distilled or “purified” water unless you plan to remineralize it.

Remineralization for distilled water is a great option if you want full control. Start with distilled, reverse osmosis, or very soft water, then add minerals back in using products like Third Wave Water, Barista Hustle Water, or DIY recipes using food-grade Epsom salt (magnesium sulfate) and baking soda (sodium bicarbonate). This method gives you precise control over your water’s composition and ensures consistency every time you brew.

Regional Water Considerations

If you’re brewing in Florida—you’re likely dealing with hard water. Florida’s limestone-rich geology means tap water often has high calcium content, leading to scale buildup and potential over-extraction. Many Florida brewers benefit from filtration or blending tap water with bottled or RO water to bring TDS and hardness into the ideal range.

Seasonal water quality changes can also affect your coffee. Municipal water treatment adjusts throughout the year based on source water conditions, rainfall, and demand. You might notice your coffee tastes different in summer versus winter—it’s not your imagination, it’s your water.

Municipal vs. well water differences are significant. Municipal water is treated and regulated, but may contain chlorine and fluctuate in mineral content. Well water is untreated, so mineral levels can vary widely depending on local geology. If you’re on well water, testing is especially important to understand what you’re working with.

Tasting is the best way to determine what YOU like!

Testing Your Results

The best way to evaluate water quality improvements is through side-by-side brewing comparisons. Brew the same specialty coffee with your original tap water and your improved water, using identical brewing parameters (grind size, water temperature, brew time, coffee-to-water ratio). Taste them side by side and note the differences.

What to taste for with improved water: 

• Clarity: Flavors should be distinct and well-defined, not muddy or muddled.

• Balance: Sweetness, acidity, and body should all be present in harmony.

• Complexity: You should notice more nuanced tasting notes—fruit, floral, chocolate, nuts—depending on the coffee’s origin and roast profile.

• Finish: The aftertaste should be clean and pleasant, not bitter or astringent.

How small beanz coffee co. coffees respond to good water: Our light-to-medium roast specialty coffees are designed to highlight origin characteristics and unique flavor profiles. When brewed with optimized water, you’ll taste the full spectrum of what each coffee has to offer—whether it’s the bright citrus notes of our Ethiopian beans, the chocolatey sweetness of our Colombian, or the fruity complexity of our Rwandan coffee. Poor water quality can mask or distort these carefully crafted flavors, so improving your water is one of the best investments you can make in your coffee experience.

Conclusion & Action Steps

Great coffee starts with great water. By understanding the science behind water quality and taking simple steps to optimize it, you can unlock flavors you didn’t know your coffee had. Start by testing your water—measure TDS, check for chlorine, and understand your baseline. Then choose a filtration or remineralization strategy that fits your budget and brewing habits. Even small improvements can make a big difference in your cup.

Ready to taste the difference? Test your water this week and brew a side-by-side comparison. You’ll be amazed at what you’ve been missing. And if you want to dive deeper into brewing techniques, water chemistry, and how to get the most out of your specialty coffee, join us for one of our hands-on brewing classes at small beanz coffee co. We’ll help you master every element of the perfect cup—from bean selection to water quality to extraction science.

Explore our current coffee offerings and sign up for a class at smallbeanzcoffeeco.com. Let’s brew something amazing together.