The water you use makes up about 99% of what’s in your cup.

The water you use makes up about 99% of what’s in your cup. It therefore has a huge impact on the taste, aroma and colour of your tea.

The perfect cup of tea captures all the senses – it will appear bright in colour with good clarity, have abundant fragrance, lasting clear and distinct flavours and a fully mouth-coating texture – some teas feel thick and velvet, some have a rounded texture and some are even honeycomb like.

If you’re not getting the full sensory experience from your tea – perhaps it sometimes looks cloudy or the taste falls flat – and you’ve already made sure you’re tea leaves are high quality, single garden, whole leaves which are fresh (there’s more about how to keep you tea fresh here). The next thing to investigate is the water you’re preparing them with.

Why is water important?

It’s simple – the water you’re using makes up about 99% of what’s in your cup. The composition of the water, for example if it’s hard or soft or which minerals are present in it, has a huge impact on the taste, aroma and colour of the cup you make.

No one master has had a greater impact on the understanding of tea making than the ancient Chinese sage Lu Yu, a Tang dynasty scholar who lived from 733–804 CE. His monumental work ‘The Classic of Tea’ was the first known study on how to properly infuse tea. This makes it a great place for us to start with understanding what water to use for tea.

Lu Yu watched the size of the bubbles as his water boiled and realised these bubbles enabled him to find precise temperatures for tea making. He realised that use water that was not too hot for green teas, would produce more astringency and bitterness in the taste. We looked at the temperature of water, how that affects the taste of your tea and made some recommendations for you to try.  An easy experiment to do at home is to taste green tea made with boiling water vs. made with the recommended 70-80°C water and see how it affects your tea.

In the Classic of Tea, Lu Yu also discovered that water from an underground spring, rather than a crowded local river, made his tea taste better than usual – and it looked much clearer. He noted the best and cleanest spring water flows slowly over granite or stone. This spring water was naturally soft and perfectly balanced in minerals like magnesium, calcium, potassium and sodium. Ultimately, it produced smooth and rich teas with impeccable, precise flavour – the perfect cup.

Whilst it's unfortunately not realistic for most of us to use our local spring to make tea, we can still control the composition of our water. Let's take a look at what filters and systems readily available to us today, to see what difference they make.

Spring Water At Source

In his monumental work ‘The Classic of Tea’, the ancient Chinese sage Lu Yu, puts a great emphasis on water quality in tea making, discovering that water from an underground spring, rather than a crowded local river, made his tea taste better than usual.

What makes water bad for tea?

Hard and Soft Water

We’re very lucky to now have ready access to good, clean water from our taps in the UK. Depending on whereabouts you are, tap water has are a variety of naturally occurring minerals, such as the calcium, magnesium, sodium and potassium which Lu Yu realised when present in the right quantities, can enhance the taste of your tea. Essentially, water is called “Hard” when there are a lot of minerals in it; and “Soft” when there are few.
If you use hard water to make tea, you’ll likely see cloudiness and you might even get a film forming on top of the tea. This comes from too many of the plant compounds in the tea attaching to the calcium or magnesium minerals in the water and changing.
If the water you use is too soft, you’ll likely get tea that is weak or insipid. This is essentially because there are not enough other minerals for the plant compounds or polyphenols – ie the parts of the leaf which give tea its flavour – to attach to, so they will not release their flavour.

Chlorine & Organic Compounds

 There are also tiny amounts of chlorine, which typically come from the cleaning process; and other volatile organic compounds like algae in tap water. Even though the amounts are tiny, water companies work with strict limits so that the levels of such chemicals are safe – they can still affect your cup of tea.
Chlorine can affect the taste of your tea in two ways. Firstly, you might be able to taste the chlorine or get a chlorine after taste. This will mask some of the lighter or delicate flavours in your tea. Secondly, the chlorine may react with the tea plant compounds releasing their flavours and changing them.
The risk with the organic compounds is that you’ll be able to taste or smell them and once again, the flavours from your tea leaves will be masked or worse, contaminated.

use a filter. The easiest way to get the best water for tea at home is to use a filter.

At home try Activated charcoal sticks

Activated charcoal sticks are another great option. They bind unwanted chemicals in the water to its surface and reduce any unwanted odours & flavours.

The perfect cup of tea captures all the senses – it will appear clear, bright & uniform in colour, have abundant fragrance and lasting flavour.

The perfect cup of tea captures all the senses – it will appear clear, bright & uniform in colour, have abundant fragrance and lasting flavour.

How can I get good water at home?

Short of living next to a clean spring with the correct mix of minerals, the easiest way to get the best water for tea at home is to use a filter.  If you live in a very hard water area like London, filtered water will also protect your kettle from excessive limescale build up.
Water filter jugs – An accessible option that will suit most applications, these refillable jugs pass your tap water through a filter cartridge. These remove sediment, chlorine, odours and metals from the water.
Finding the right filter is the key to getting your balanced water work for tea making at home. We’ve tested many different filters with London water and our preferred choice us BWT and their range of Soft Filtered Water.
In a side by side tasting with other filters, this BWT filter consistently produced the best cup of tea. Using our Assam Breakfast with milk, Ali Shan and Sencha, we measured appearance by looking at the clarity and brightness of the infusion; aroma and taste by assessing whether the infusion delivered these optimally or whether there were any taints or weaknesses; and texture – looking at whether the tea was mouth coating.
Filters to avoid are ones that promise 100% removal of everything – like Epic or Zero. They may be good for drinking water, but when we tested them for making tea, the tea was weak and very light. With no minerals or compounds in the water, the flavour-giving compounds in the tea did not have anything to attach to and share their flavours.

Activated Charcoal stick, also known as Binchotan Charcoal

Activated charcoal sticks have been used in Japan since the 17th century as a simple and sustainable way to filter water. They’ve since gained popularity all over the world. All you have to do is place the sticks in a jug or water container and the porous charcoal will bind unwanted chemicals in the water to its surface and reduce any unwanted odours and flavours; the activated charcoal itself being odourless, tasteless, and completely nontoxic.

We included these in our taste test and were very impressed with the results. Water filtered in this way produced full flavoured and clear tea.

The small downside is that the stick takes 4-8 hours to filter any water, so you do need to be prepared, but the big benefit over the more conventional water filters is their minimum environmental impact. Each stick lasts many months, and when spent can be simply buried in the garden where the soil gain nutrients from the charcoal. Water filters tend to be made from plastic and last just a few weeks. For these reasons, it’s my personal preferred choice for filtering my water for tea.

You can find out more about the charcoal filter we tested here.

We’d love to know how the water in your area affects your tea – and any tips or tricks you use to get the best cup of tea for all of your senses. Leave your comments and thoughts below.