Can You Make Coffee with Reverse Osmosis Water?

Purification Process

Reverse osmosis (RO) water is purified through a semi-permeable membrane that filters out dissolved solids, including minerals. This results in water with a near-zero TDS (total dissolved solids) level, which can affect the taste and quality of coffee. To improve the taste, consider adding a mineral-rich water conditioner or using a water filter specifically designed for coffee brewing.

Coffee Brewing Considerations

When brewing coffee with RO water, it’s essential to maintain the optimal water-to-coffee ratio. Aim for a ratio of 1:15 to 1:17 (one gram of coffee for every 15-17 grams of water). RO water’s low mineral content can lead to over-extraction, resulting in a bitter taste. To prevent this, adjust the brewing time or use a paper filter to absorb some of the excess minerals.

Mineral Addition Techniques

If you still want to use RO water, consider adding minerals to improve the taste. You can add a pinch of sea salt or a mineral-rich water conditioner specifically designed for coffee brewing. Another option is to use a water filter that adds beneficial minerals back into the water, such as a filter with a built-in mineral addition system. When experimenting with mineral addition, start with small amounts and adjust to taste, as too many minerals can affect the flavor.