Tea definitions and which tea to drink?
All of the different varieties of tea whether black, white, green, yellow, oolong or pu erh are made from hundreds of different cultivars of the same plant, Camellia Sinensis. Tea making is hard work and there are many factors that influence the style of tea produced such as the variety of tea plant, terroir, elevation, season, age of the plant, type of leaves picked and processing method. There are simply thousands of different teas out there and this is where art meets science and the skill and craftsmanship of the tea maker comes into play.
Black tea is the most oxidised of all of the teas. The process starts by withering or wilting the leaves which causes both water loss and chemical changes within the leaf. Different lengths of wither create very different styles of black tea. After withering the leaves are rolled or crushed to burst the cells and release juices (enzymes) that start the oxidation process which turns the leaves brown. The aromas that are released in this part of the process are simply incredible, aromatic and fresh and for me this is one of the "magical moments" in the process. Great care needs to be taken with this part of the process ... too much oxidation and your tea will taste flat! After oxidation the leaves are fired or dried down to around 3% moisture. Too much drying and you burn off the essential oils leaving the tea with a nasty "bakey" flavour too little and the tea won't keep. Black tea that is well fired will keep for years as long as you store it in a cool dark container and keep it dry.
Black tea like red wine also contains antioxidants that can help protect your cells from DNA damage. These are called Polyphenols and they affect both the colour "mouthfeel" and flavour of black tea.
The stimulant effects of tea differ from coffee due to the amino acid L-Theanine which "evens out" the effects of caffeine. This means that tea has relaxing properties that don't cause drowsiness and stimulating properties that can improve speed, performance and accuracy.
Green Tea varies in the same way that black teas vary according to terroir, season, cultivar etc. with another variant that depends whether the plants are either shade or sun grown. The key to producing green tea is to prevent the leaves from oxidising, the leaves are withered usually for a shorter time than you would to produce black tea and then quickly heated. Chinese green teas are traditionally pan-fired, as opposed to the Japanese teas which are produced by a steaming process. Very few black teas are made on a small scale with artisanal methods but many green teas are still produced by "tea masters" using methods that are centuries old. After the initial "kill green" heating, the leaves are rolled and shaped and then dried, green teas can be re-fired several times to prolong shelf life and improve flavour. Expect the unexpected with a green tea, flavours range through sweetly floral to savoury asparagus, seaweed, nutty or even resemble a chicken stock. The secret is all in the brewing. Use boiling water on green tea and you can expect a nasty bitter brew, take a little care and you will be well rewarded.
Oolong or Wulong Tea
Oolong or Wulong Tea is semi-fermented and having worked throughout the night to make oolong myself I can tell you it's a very demanding tea and a real challenge for the artisan maker. After withering in the sun, the leaves require "rattling" every two hours to cause semi-oxidation by gentle bruising around the edges and along the veins of the leaf. The leaf is then roasted, quickly cooled, shaped and roasted again. Oolongs vary widely and can taste nutty through to fruity and vary in colour when brewed from yellow through to a red. I always feel like I'm on a mini adventure every time I try a new oolong, it's a tea that's well worth exploring, there's a lot to choose from and you are sure to find a favourite.
White Tea is not oxidised in any way and is one of the simplest yet most difficult teas to produce. Really great white teas have a wonderfully delicate floral flavour and aroma. I feel like I develop a halo and grow a pair of wings whenever I drink white tea. Silver needle tea is made from the buds and Bai Mu Dan from the whole leaves. To make a white tea, leaf is firstly withered outdoors under the sun followed by slow withering and drying at a controlled room temperature with good air circulation. This process usually takes more than 12 hours and is not as easy as it sounds, the key is to control and manage moisture loss and moisture distribution within the leaf. It's very easy to damage the leaves during processing which will kick start oxidation, turning the leaves black and will destroy the flavour and if you get the drying wrong its easy for the finished tea to taste stale.