But when it comes to water temperature, there might, possibly, be room for improvement …
It’s generally acknowledged, among professional tea manufacturers, that you should not pour boiling water onto tea. (Many of us, of course, do just that.) How hot, then, should the water be?
The optimum water temperature varies according to the type of tea you’re making. And the type of tea depends on the extent to which the tea leaves have been oxidised.
All teas are the dried leaves of Camellia sinensis. The difference between white, yellow, green, oolong, and black tea lies in the degree of oxidation. Green tea, for example, is hardly oxidised at all, while black tea is almost fully oxidised.
Like many plant species, Camellia sinensis contains polyphenols – a group of organic compounds that includes catechins (deterrent to predators) and tannins (regulation of the plant’s growth and ripening). Through the process of oxidation – catalysed by polyphenol oxidase, an enzyme that occurs naturally in the tea plant – catechins are converted to other types of polyphenols called theaflavins and thearubigins. These chemical compounds give black tea its colour, comparable to the browning of apple flesh, which oxidises when exposed to air.
Oxidation (loss of an electron) is one half of a redox reaction. The other half of the reaction (the gaining of an electron) is reduction. In the case of tea, the oxidising agent – i.e. the chemical that’s being reduced – is oxygen. Although the term “oxidation” comes from “oxygen”, a redox reaction doesn’t always involve oxygen.
Green tea is an excellent antioxidant because the catechins in the tea are available for oxidation in the body. By donating an electron to an unstable chemical (free radical), catechins can interrupt the chain redox reaction that’s associated with ageing.
Water that’s too hot will scald the tealeaves, giving the tea a bitter taste. The greater the extent of oxidation, though, the better the tea can withstand high temperatures. If the water’s too cool, the tea’s flavours won’t fully infuse the water.
So, here’s a rough guide to the optimum water temperature for the various types of tea:
There are approximately 120 species in the genus Coffea, but only a few of these species are cultivated for their caffeine-rich seeds, which are roasted, ground, and infused in hot water to produce one of our favourite drinks.
Two species account for roughly 99% of the world’s cultivated coffee. Coffea canephora is best known as robusta, which is the name of one of the two C canephora varieties. Coffea arabica is a hybrid of C canephore and C eugenioides.
There are several ways of brewing coffee:
There are three main variables in coffee brewing: 1. time; 2. grind; 3. temperature. Here, we’re concerned with temperature.
Water that’s too cool will fail to extract the coffee’s flavours, whereas water that’s too hot will over-extract, producing a bitter brew. The optimum temperature for coffee is 95°C.
Coffee and tea both have a PH of approximately 5. This slight acidity is a major feature of their flavour profiles.
UK government regulations stipulate that mains water has a PH value of between 6.5 and 9.5, so in many cases, our water is slightly alkaline. The alkalinity of mains water will lower the overall PH of coffee and tea. Pure water, however, has a neutral PH of 7, so it allows the mildly acidic flavour of tea and coffee to be expressed.
If you’d like to know more about Aqua Libra Co water dispensers, download our products brochure, or contact us by phone on 0800 080 6696 or by email at firstname.lastname@example.org.