Hard water ruining your tea? How to brew a perfect cuppa from a London tap

If there was one "boring buy" I knew I wanted to make last year, it was a kettle with a built-in water filter.

In all my years of living in London, I've always viewed limescale as my nemesis. And I'm certain I'm not alone. Most Londoners will see our city’s hard water as either a mild annoyance or a genuine challenge to our daily lives. There wouldn't be a market for shower filters that minimise the effects of hard water minerals if this weren't a problem!

What I'm here to talk about, though, is what London’s water is doing to the most essential of British drinks. A proper brew. A cuppa. Tea, of course.

While coffee may be gaining popularity, YouGov data shows we're still a nation of tea drinkers. For 71% of us, traditional black tea (with or without milk) is the top choice, according to the UK Tea and Infusions Association (UKTIA).

Intrinsically, you and I both know hard water and tea don’t get along. You can see the change in appearance when your water’s full of limescale – it looks murkier, and the taste doesn’t live up to your expectations.

What's really in your cuppa

What’s actually happening here? I asked Henrietta Lovell, the founder of the Rare Tea Company, to get to the truth about what hard water’s doing to our brew.

“Tea is, of course, mostly comprised of water. It's an infusion of camellia sinensis leaves. Some of the delicious compounds held in those leaves dissolve into the water. So it's not surprising that the water will affect the flavour,” Lovell said.

“London's hard water contains higher levels of minerals, like sodium bicarbonate, that can negatively impact the flavour of the infusion.”

2016 research from the World Academy of Science, Engineering and Technology found that the water used plays a “major role” in the quality of tea, concluding that “bad quality water gives bad tea with inferior liquor which has undesirable qualities.” Thanks, science.

“The minerals in hard water (especially calcium) will not only alter the taste of the tea but can also leave an unattractive scum on the surface of the cup - this is exactly the same as the limescale that builds up in a kettle in hard water areas,” Ottilie Cunningham, Tea Buyer for Fortnum & Mason, told me.

“The minerals bind to the compounds in tea, which give its flavour, thus dulling the taste and sometimes appearing as bitter or metallic.”

What do London’s most famous afternoon tea spots do to tackle our hard water, then? They use water filters – and the highest-quality tea!

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“We aren't chemists or water experts at Rare Tea, but we are flavour experts based in London. And we have noticed we can get an even better cup of tea using filtered water,” Lovell said.

“When you filter your water, you're allowing more of the tea's true flavour, aroma and character to come through.”

So is the answer that your water needs to be filtered if you want it to taste as good as it would fresh from the pot at Claridge’s or Fortnum’s? Yes, but that’s not the only tip.

“The most important part of brewing a great cup is the water, using filtered if possible, but always freshly drawn and freshly boiled,” Cunningham said. “Water deoxygenates when it boils, so repeated boiling will make the tea taste flat.”

And while my in-kettle filter is decent, it’s not the end of the story when it comes to filtration tech. Lovell told me that Rare Tea uses an under-sink filter because filters in the kettle may only remove larger particles. Before you go ahead and install one, though, it’s worth knowing that there’s more than the water that’ll make a real difference. You might need to change the kind of tea you’re buying.

Tea types, temperatures, and brewing times

“If you really want to transform your cup, switch to loose-leaf tea,” Lovell recommends.

“The bag also has a flavour. It's made from paper or plastic mesh that has been processed with industrial bleaches, solvents and a host of chemicals. They also dissolve with the boiling water in the cup.”

Research shows that tea bags release billions of micro- and nanoplastics into your cup, so they could be worth avoiding in favour of a good old-fashioned teapot or strainer.

Even with loose-leaf, you’re going to want to make sure you’re brewing the right way to deliver the most flavour. Last year’s UKTIA Tea Census Study found that far too many of us are rushing and only brewing tea for a couple of minutes.

“Three quarters (73%) of those surveyed admitted to leaving their tea to brew for less than the three to four minutes we at the UKTIA would recommend for the ideal cup of regular black tea,” said Dr Sharon Hall, Chief Executive of the UKTIA.

The essential tips? Store your tea away from strongly perfumed foods, use freshly boiled water (filtered, if possible), let the tea brew for long enough (most need three to four minutes, but look at what’s recommended on the packet!) and don’t overdo it.

You don’t need to use too much tea or squeeze the teabag against the side of your cup – it can ruin the taste. And take note of which tea varieties don’t need fully boiled water, as different types prefer different temperatures; you’d only need water at 65°C for white tea, for example.

Also, avoid boiling water over and over again. Just make the exact amount you need for your cuppa. It’s better for the tea and for your energy costs. And, apparently, warming your teapot or mug could help with the brew, too. Who knew?

The leaves that reward you

Which teas transform the most dramatically once water quality is addressed? Unsurprisingly, it’s not your average PG Tips or Yorkshire bags.

“White teas and green teas are the most sensitive,” Lovell explained.

“These are delicate teas with subtle, nuanced flavours – and any harshness from chlorine and heavy minerality in the water will overpower the delicacy and mask what makes them special.”

It’s not all bad news for Londoners, even if you can’t be bothered to wait for your water to filter before boiling. Your hard (or soft) tap water probably isn’t a disaster.

“Recent research found that tea can actually absorb metals in water, potentially improving the water quality itself. Camellia sinensis is an incredible plant – it improves your water quality as well as giving you antioxidants, stimulating caffeine and mood-enhancing L-theanine,” Lovell told me.

“Different teas actually react differently to hard and soft water, so it's definitely worth experimenting with different tea origins in your water,” Cunningham said.

If you take anything away from this article, though, it should be to focus on using good-quality tea, follow the brewing instructions, and consider picking up some loose-leaf if you want a noticeable upgrade.

And, if you’re still interested in my kettle, it’s the fantastic Russell Hobbs Purity. It boils quickly and is great at filtering London’s hard water to deliver a non-murky and better-tasting cup. Unless you’re worried about the ongoing cost of filters, it’s not exactly overpriced, either, at £38. What more could you want?

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