And which teas benefit most from good water
It is important to appreciate that the quality of the water used to brew your tea is one of the most important determinants of what makes a good cup. Some tap water, especially in hard water areas will impact profoundly on the taste, whereas in areas with moderately hard or soft water the impact will be less crucial or even beneficial to the taste.
Hard water
The map alongside depicts water hardness in the UK as measured by the concentration of calcium carbonate and magnesium in mg per litre. Hard water can fail to allow delicate flavour components of your tea come to the fore. It can also make tea taste bitter and can leave an unpleasant scum on the surface of your tea. This is all too apparent to those in London and South-East England where water is drawn from chalk bearing aquifers. Scotland, Wales, Northern Ireland, and parts of the north-west generally have soft or moderately soft water well suited to making good tea.
These are the counties with particularly hard water which can compromise the flavour of tea: Kent, Essex, London, Hertfordshire, Bedfordshire, Buckinghamshire, Berkshire, Surrey, Cambridgeshire, Northamptonshire, Lincolnshire, Norfolk and Suffolk.
Spring water
The best way to resolve the problem of hard water is to use spring water with a moderate mineral content, of below 50mg total dissolved solids per ltr. and a neutral pH. This gives a naturally balanced, clean taste. Volvic is considered the best by many, bringing out the character of the tea. Evian, also widely available, has a higher mineral content but is considered ideal for black tea, giving a smooth, well-balanced brew. Highland Spring is a soft water with a light mineral content well suited to making tea.
Filtered water
Filtered tap water is the next best to use for making good tea but the suitability depends upon water quality and the type of filter used. Distilled water should not be used for making tea as the result will be flat and lifeless as there is no mineral content. It is this moderate mineral content which helps ‘carry’ the flavour components of the tea. A filter can help improve the character of your tea in areas of moderate water hardness especially if you live in these counties: Oxfordshire, Warwickshire, Leicestershire, Nottinghamshire, Worcestershire, Gloucestershire and parts of Yorkshire.
The best type of filter is activated carbon and ion exchange used with a water jug such as the popular Brita brand. It reduces chlorine, which can dull tea aromas, and hardness but keeps enough minerals to avoid producing flat-tasting tea. It is inexpensive and easy to maintain.
If water is exceptionally hard (above 250–300 mg/ltr.), a stronger filter such as a ZeroWater system can make a major difference by removing nearly all dissolved minerals, creating a brighter cleaner cup of tea. It is particularly well suited to making Darjeeling, green and white teas. However, some tea lovers find that the water can be too pure leaving the taste a little flat.
If you live in an area with soft water a carbon filter can be used to remove chlorine.
Teas that are improved most with spring or filtered water
The teas that benefit most from using spring or filtered water are those with delicate, complex flavours. Hard water tends to suppress floral, fruity and sweet notes, whilst spring and filtered water lets those characteristics shine through. Below is a table highlighting which teas benefit most from using spring or filtered water:
| Tea type | Benefit from filtered water /5 | Why |
|---|---|---|
| Japanese green teas (Sencha, Gyokuro) | 5 | Delicate umami and sweet notes are easily masked by hard water. |
| Chinese green teas (Long Jing, Bi Luo Chun) | 5 | Softer water enhances sweetness and freshness. |
| White teas (Silver Needle, White Peony) | 5 | Very subtle flavours become more pronounced. |
| Light oolongs (Tie Guan Yin, High Mountain Oolong) | 5 | Floral aromas are cleaner and more expressive. |
| Darjeeling First Flush | 4 | Muscatel and floral notes are easier to detect. |
| Chinese black teas (Keemun, Yunnan) | 4 | Greater clarity and sweetness. |
| Second Flush Darjeeling | 4 | More defined fruit and muscatel character. |
| Assam | 3 | Smoother, but still performs well in moderately hard water. |
| Ceylon | 3 | Brighter cup, though less dramatic improvement. |
| English Breakfast blends | 2 | Designed to be robust and forgiving. |
| Pu-erh | 2 | Generally less sensitive to water hardness. |
| Herbal infusions | 2 | Some improvement, but flavour is less affected than true teas. |