The Science of Coffee Brewing: How Water Quality and Temperature Affect Your Coffee

Coffee isn’t just a drink—it’s a ritual, an artform, and for many, a non-negotiable part of the morning. But even the most premium beans and state-of-the-art brewing equipment won’t deliver that rich, full-bodied flavour you’re chasing if you overlook two critical elements: water quality and temperature. Let’s dive into the science behind these often-forgotten factors that make or break your morning cup.

Why Water Matters More Than You Think

Did you know that coffee is roughly 98% water? It’s easy to focus on the beans—single origin, freshly roasted, ethically sourced—but the water that extracts those complex flavours plays just as crucial a role. Poor-quality water can distort taste, mute aromatics, and even damage your equipment. Water that’s too hard (high in minerals) may over-extract your coffee and leave bitter flavours, while water that’s too soft might under-extract, resulting in a flat, dull brew. That’s why many baristas and coffee lovers are now paying close attention to water quality and coffee brewing. Using pure, mineral-balanced water—like that from natural spring sources—can significantly enhance flavour clarity, mouthfeel, and aroma.

Temperature: Not Too Hot, Not Too Cold

Brewing temperature isn’t just a technicality; it’s a game-changer. Coffee solubles extract best within a very specific temperature range—usually between 90°C and 96°C. Stray outside this, and you’ll notice the difference.

• Too hot, and your coffee may taste burnt or overly bitter.
• Too cool, and you’ll get an underwhelming, sour flavour profile due to insufficient extraction.

Consistency is key. Investing in a quality kettle with temperature control can help maintain the sweet spot, ensuring your brews are always balanced and flavourful.

The Synergy of Science and Taste

The harmony between water quality and temperature can unlock a depth of flavour in your beans that might otherwise go unnoticed. Think fruity notes, caramel sweetness, silky textures—achievable with the right combination of water chemistry and heat. For those seeking to elevate their home coffee experience, start with your water. A good rule of thumb is to use filtered or spring water that’s free of chlorine, odours, and excess minerals. Then, pair that with precise temperature control to bring out the best your beans have to offer.

Final Sip

Great coffee doesn’t just happen. It’s the product of careful attention to the science behind brewing—something as simple as water can be your biggest ally or your worst enemy.

So next time your brew tastes a little off, don’t be too quick to blame the beans. Take a moment to assess your water source and temperature. You might just discover the missing piece to your perfect cup.