How water filtration influences the sensory perception of tea


Birgit Kohler, Head of Organoleptic Department at BRITA, explains how water filtration influences the sensory perception of tea.

According to water filtration systems company BRITA, 46 per cent of consumers don’t believe the quality of tea is any better in cafés than at home. Head of BRITA’s Organoleptic Department Birgit Kohler says this means there is clearly space for tea to grow in the hot beverage sector.

“Right now, many consumers will be well acclimatised to making a brew in the comfort of their home due to the COVID-19 lockdown periods,” says Birgit.

“This presents a clear opportunity for cafés to improve their offering and attract the discerning tea drinker into their establishment.”

Birgit says it’s evident that hot beverage businesses need to add the ‘wow’ factor to the beverage to make it an out-of-home occasion for consumers.

“We know that great coffee keeps patrons coming back to a café again and again, why should tea be any different? It’s time we start delivering high-quality hot beverages to tea lovers too,” she says.

As an industry, Birgit says cafés need to evaluate how to improve offerings
so that tea sales rise in the out-of-home market.

“Tea is no longer just a glass of hot water and a random teabag. Café operators and baristas have educated consumers in the last years about the differences in coffee, so let’s go about enhancing consumers’ sensory world with tea. There are a lot of sensory experiences waiting to be discovered,” she says.

To demonstrate the effects of filtered water, BRITA’s Organoleptic Department conducted a tea test using one cup of tea brewed with filtered water and another with unfiltered water. In the latter cup, a white film appeared on the water’s surface, and the tea became dark and turbid.

“When water and tea meet while brewing, substances are dissolved. This process is called extraction. Depending on the type and quality of tea and the composition of used water, different flavour experiences can be created. For example, the tea with unfiltered water tasted flat. Fruity and flowery aromas don’t get through,” Birgit says.

“This is because unfiltered water can contain impurities including chlorine, organic compounds and limescale, all of which can affect the flavour and dull its appearance, making the drink less appealing.”

If water contains a high level of carbonate hardness, Birgit says there is more hydrogen carbonate in the water, which reacts with the fine acids of the tea.

“When these acids are missing in the tea, fruity and flowery aromas are perceived as not very intense. This is because the corresponding sour taste via the tongue’s receptor cells to the odour component is missing. It’s not only a matter of weak aromas, but also about sourness, astringency and bitterness. These attributes need to be in a balance for perfect tea,” she says.

BRITA says there is a clear opportunity for cafés to improve their tea offering and attract discerning tea drinkers into their establishment.

“The so-called total hardness is responsible for the turbidity of tea with unfiltered water. Cross-linking reactions with the polyphenols of the tea occurs, which can be observed particularly well when the tea is left to stand overnight. In the next morning there is a coherent film on the tea: the tea scum.”

Birgit says filtered water is the best way to address concerns of water taste to ensure the best tasting tea for a café and its patrons. Water filtration removes a lot of unpleasant water ingredients like chlorine and organic compounds from regular tap water that oral and nasal receptor cells pick up.

“Some of these organic compounds have very low threshold values, meaning they can be noticeable even in very small quantities,” Birgit says.

“All BRITA water filtration systems reduce chlorine and organic water compounds and almost all also adjust the mineral level. BRITA filters can save your café equipment from limescale build-up and the like, as they catch lime before it makes its way to your kettle or espresso machine,” says Birgit.

“Tea is a water-based beverage. It consists of more than 98 per cent of water. To serve a good tasting cup of tea, you should ensure you use the right one.”

She adds that water temperature is another crucial factor that affects extraction (see breakout box).

“Some bitter flavours are better soluble in warmer water. Particular teas require these ingredients for a holistic, typical flavour like black tea and dark

oolongs. Other teas like white, yellow and greens do benefit from lower temperatures. The delicate, sweeter aromas would be dominated by the bitterness if the temperature of the water was too high,” says Birgit.

“The best water for tea should be soft, but not too soft. I would recommend a buffer capacity between two to five degree German water hardness and a total maximum nine degree German water hardness. And it should be free of any odours.”

Birgit says by educating consumers on the importance of water filtration for tea in a café, coffee shop or other business environment, the hot beverage industry has the potential to flourish in a whole new sector.

“Most consumers already experience that tea with filtered water is more appealing and tastier. We at the Organoleptic Department take care of the science behind your cup. The preference for tea is influenced by various factors and will ultimately vary from person to person. We connect chemical facts and research with taste and consumers experience.

Based on different standards for organoleptic testing, for every question we choose a suitable methodology. Sometimes several methods are necessary to answer a rather simple question,” she says.

“In a nutshell, water sensory is a young fascinating science and we ensure that the customer enjoys the BRITA water filtration experience.”

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This article appears in the October 2022 edition of BeanScene. Subscribe HERE.

Title: Brewing temperatures of different teas

·      White tea: 80°C

·      Yellow tea: 80°C

·      Green tea: 75-80°C

·      Oolong tea: 90°C

·      Black tea: 95 to 98°C

·      Dark tea (e.g. Pureah): 95 to 98°C

Title: Recommended steep times of different teas

·      White tea: five minutes plus

·      Yellow tea: two to three minutes

·      Green tea: Chinese two to three minutes, Japanese 0.5 to one minute

·      Oolong tea: three minutes

·      Black tea: Small particles 1.5 to two minutes, medium leaf two to three minutes, large leaf three to five minutes

·      Dark tea (e.g., Pureah): two to three minutes

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