Water Condition for Brewing Coffee

The correct water condition to brew coffee

People often buy coffee from a particular place where they have enjoyed an excellent cup. They take the coffee home, brew it correctly and wonder why it doesn't taste the same. As a cup of coffee is more than 98 per cent water, the condition and taste of the water are at least as important as the coffee used, and only water from the same source will recreate an exact taste. Coffee experts tend to agree that the best water for brewing coffee is slightly hard; a few minerals will enhance the coffee flavor, hence the old custom of adding a pinch of salt to "bring out the flavor". If the brewing water is very hard, however, the calcium and magnesium ions can actually get between the water molecules and the coffee particles, interfering with the extraction process, and the resulting brew will have little flavor.

When considering the effect of soft water in brewing coffee, it is interesting to examine the softest water possible, which is distilled or de-ionized; as water it has virtually no taste, and no one would dream of making coffee with it. It could therefore be assumed that coffee made with distilled water would also be tasteless and would need a "pinch of salt to bring out the flavor". Wrong! Because it contains nothing to interfere with the extraction, coffee brewed with tasteless, distilled water has a very strong coffee flavor, which in the course of normal brewing, especially with a cheap blend, could easily be far too strong. Very soft water requires less coffee per brew, or a slightly coarser grind, or less contact time - any of which work to ensure that over-extraction does not occur. The old wives' habit of adding a pinch of salt may have worked not in "bringing out the flavor", but rather in toning it down, modifying the flavor for the better, if the original water was very soft.

Chlorinated or other chemically treated water, or water polluted by old pipes, rust or other tastes can affect the flavor of coffee. Filtering devices, which remove objectionable tastes, are available both in jug (carafe) form and in more permanent systems that attach to the kitchen main water pipe.

Generally, experts agree that fresh, cold water, which presumably has a higher oxygen content, makes the best coffee. Somewhat confusingly, however, it is oxygen that causes ground coffee to go stale, and it is from oxygen that vacuum flasks protect liquid coffee. Thus the need to have oxygen in the brewing water seems surprising, especially as convincing scientific explanations are rather scarce. (This calls for the challenge of a taste test: try brewing the same coffee with stale, warm water and with fresh, cold water and observe the difference.) Remember that most electric coffee-makers are equipped with thermostats which expect to start with cold water, and may not function very well if hot water is used.

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