More than 98 percent of a cup of pour-over coffee is water. Water is not only the carrier of flavor, but also the key solvent that determines whether the aromatic substances in coffee beans can unfurl. If you want the coffee in your cup to taste mild and smooth, with neither a sharp acidity that makes you frown nor a harsh, astringent burnt-bitterness, then besides choosing the right roast and origin, selecting the right water quality for your pour-over kettle often brings unexpected surprises.

The impact of water on coffee flavor centers on the total dissolved solids in the water, that is, TDS, as well as the content of calcium and magnesium ions and bicarbonate. Calcium and magnesium ions are like diligent little helpers, responsible for drawing out the aromatic esters and sugars from the coffee grounds; bicarbonate, meanwhile, plays the role of buffering acidity. If the mineral content in the water is too high, it easily over-extracts bitter and astringent impurities; if there are too few minerals, the flavor appears thin and sharp.

When brewing coffee at home day to day, tap water straight from the tap and then boiled often has relatively high hardness, and the resulting coffee easily tastes dull and bitter, with the aroma unable to open up. If you use reverse-osmosis purified water or distilled water, because it lacks the assistance of minerals, the extracted coffee often appears prominently acidic and lacking sweetness to support it, with an empty finish, always feeling not full or rounded enough.

For coffee lovers pursuing a warm, smooth mouthfeel, choosing lightly mineralized water with a TDS between 50 and 100 mg per liter is very hassle-free. Common natural soft mineral water or quality natural water on the market has a moderate mineral content, which can gently dissolve coffee's native harsh fruit acidity while fully extracting the delicate caramel sweetness and floral-fruity aromas inside the coffee beans, giving the whole cup a just-right sweetness on entry.

Once the water quality has been adjusted properly, choosing light-to-medium roasted single-origin beans with a moderate roast and a flavor leaning toward warm sweetness makes it easier to achieve an approachable mouthfeel. For example, Qianjie Ethiopia Huakui is a bean very well suited to this kind of water quality. It naturally carries lively passion fruit and ripe strawberry aromas, and as long as the water is used properly, the brewed coffee is like a cup of warm fruity sweet tea, with soft acidity and full sweetness.

When brewing Qianjie Ethiopia Huakui, it is recommended to prepare 15g of coffee grounds, use a 1:15 coffee-to-water ratio, pour in 225ml of lightly mineralized water, and set the water temperature at 90°C. First pour in 30ml of water for a 30-second bloom, then use a three-stage pouring method. In the second stage, pour steadily to 130ml, and after the liquid level drops slightly, pour the remaining water to 225ml. Control the total time at 2 minutes 05 seconds. The coffee brewed this way has a crisp fruity aroma and a continuous sweetness.

If the water on hand has a slightly higher mineral content, the overall extraction efficiency will speed up. In that case, you can choose bean varieties with more restrained aromatics and a tea-like, sweet aftertaste to pair with it. For example, Qianjie Kafa Forest performs very steadily. This bean has a rounded flavor like ripe apricot and orange, and as the temperature slowly drops, it also releases a comfortable oolong tea note, entering the mouth mild and smooth.

Given the characteristics of Qianjie Kafa Forest, we can still use the 1:15 pour-over plan of 15g grounds with 225ml water, adjusting the water temperature slightly to 91°C. Adjust the pouring technique to a two-stage pour: first pour 35ml of water and bloom for 30 seconds, then pour the remaining water in a steady circular stream to 225ml and stop. Control the total time to finish at 1 minute 55 seconds. The acidity of the whole cup is naturally dissolved, and the mouth is full of clear, sweet, refreshing tea aroma.

If you are used to making espresso with an espresso machine and then adding water to make a mild Americano, water quality likewise governs the thickness of the crema and the balance of flavor. Using soft water can better showcase the bean's clear sweetness. Here, using Qianjie Kenya Little Tomato to make it is very appealing. Take 18g of coffee grounds and extract at a constant 9 bar for 26 seconds to obtain 36g of espresso liquid. Its signature cherry tomato and yellow sugar sweetness is especially distinct, and after adding hot water it is smooth and refreshing.

If at home you currently only have a purified water filter, you can also try the little method of mixing seven parts purified water with three parts commercially available mineral water to make yourself a pot of brewing water with moderate softness and hardness. This approach can balance the mineral ions in the water at extremely low cost, allowing the fruit acidity and cocoa-caramel flavors in the coffee grounds to be released evenly. It tastes neither sour nor astringent, and the base of the tongue is full of sweet aftertaste.

Delicious coffee never needs a complicated mystical threshold. As long as you pay a little attention to the water quality in the pour-over kettle, and then pick a bag of coffee beans with soft aroma and ample sweetness, you can easily brew a smooth, warm, good flavor at home. Handle the water temperature and time steadily, and every sip lets you feel coffee's original purity and sweetness.