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What is the ideal TDS for pour-over coffee water and how does water quality affect pour-over coffee?

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, To brew delicious coffee, not only do you need quality beans, but water quality must also be excellent. Considering that in brewed coffee, water constitutes over 98% of the content. Therefore, selecting suitable water for brewing coffee is also crucial. So what kind of water is actually suitable for brewing coffee? First, FrontStreet Coffee will explain the requirements for water suitable for brewing coffee.

The Importance of Water Quality for Brewing Coffee

To brew delicious coffee, not only do you need good beans, but the water quality must also be excellent. In brewed coffee, water accounts for over 98% of the content. Therefore, choosing the right water for brewing coffee is crucial. So what kind of water is actually suitable for brewing coffee?

Requirements for Coffee Brewing Water

First, FrontStreet Coffee will explain the requirements for water suitable for brewing coffee. Generally, there are two main requirements for water used in coffee brewing: one is hardness, and the other is pH level.

Water Hardness

Let's start with hardness. Water that appears clean in nature is not pure water containing nothing. Water typically contains ions such as calcium, magnesium, potassium, sodium, as well as bicarbonate ions. These substances in water affect its softness and hardness, and generally, hard water is not suitable for brewing coffee.

The TDS (Total Dissolved Solids) standard for coffee water recommended by SCAA is 75-250ppm, but in practice, water with TDS below 100ppm is more likely to produce delicious coffee.

This is because TDS data only indicates the amount of soluble substances in water, but cannot clearly specify the composition and content of these substances.

Scientific research shows that an appropriate amount of calcium ions in water can better dissolve the acidity of coffee, but water with high calcium content easily forms scale. A small amount of magnesium ions in water can enhance the sweetness and aroma of coffee. Therefore, water containing appropriate amounts of calcium and magnesium ions is very suitable for brewing coffee.

pH Level

The pH level of water also affects the taste of coffee. A pH value of 7 indicates neutrality, with smaller numbers indicating higher acidity and larger numbers indicating higher alkalinity. Coffee has a pH value between 5-6, making it slightly acidic. Generally, water with a pH value between 6.5-7 for brewing will produce more palatable coffee.

Types of Water for Coffee Brewing

Based on the above conditions, tap water should be the first to exclude. The TDS value of tap water in most regions is relatively high. You can observe your home's kettle to see if there's a layer of white scale.

Even if tap water in some areas meets the TDS standards for coffee water, it contains residual trace amounts of chlorine, which is why we can smell a swimming pool-like odor in tap water. Coffee brewed with this water typically exhibits a gritty texture and mixed flavors.

If you use filtered tap water at home, you also need to test the TDS value and try brewing to compare whether the taste has improved. This is because some filters are not very effective, and the filtered water remains unsuitable for brewing coffee.

Secondly, pure water containing nothing is also not suitable for brewing coffee. As FrontStreet Coffee mentioned earlier, appropriate amounts of calcium and magnesium ions can promote coffee extraction, enhancing the acidity, sweetness, and aroma of the coffee. Coffee brewed with pure water containing no substances will have an inexplicable hollow feeling, and the lack of sweetness and aroma will make the acidity taste sharp.

Mineral Water for Coffee Brewing

The last option that's relatively easy to use is mineral water. When purchasing mineral water, you must check the mineral content on the label. Never judge water quality by price. For example, the premium-priced Evian water has a TDS of 489ppm, far exceeding the maximum TDS value for coffee water, making it unsuitable for brewing coffee. If you need to buy mineral water for brewing coffee, it's best to check the TDS value on the label and the content table of various minerals.