Aged white tea

White tea has many unique characteristics, with aged white tea having different health benefits from the fresh one being one of them.

At white tea’s birth place Fu-Ding area of the Fu-Jian Province in China, aged white tea has long been used to treat symptoms associated with measles, especially before the era of using western medicine for fever control. It’s also well known for functions such as treating alcohol hangover & tooth aches, detox and cancer prevention etc. Aged white tea’s medicinal properties have been passed down as traditional wisdom for many generations and became a source of interest to modern research.

Main differences in bio-chemical composition of white teas of various ages

Dr Zhou from the Fu-Jian Agriculture University conducted a study in 2014 compared some main compounds of fresh, 1 year, 3 years and 20 years white teas with following findings:

White tea	Tea Polyphenols (%)	Caffeine (%)	Amino acid (%)	Sugar (%)	Flavonoid (mg/g)
Fresh	22.7	4.28	3.9	2.74	5.67
1 year old	21.4	3.63	3.89	2.76	6.94
3 years old	20.2	3.49	3.81	2.7	5.95
20 years old	8.2	2.52	0.32	1.96	13.26

 

As highlighted, a striking difference in the contents of the teas is the flavonoid level of the 20 years old white tea. Flavonoid is a main part of the tea polyphenol composition and has been demonstrated to be a powerful anti-oxidant, responsible for many tea health benefits such as cancer prevention, anti-bacteria, anti-virus and reducing blood cholesterol levels.

Due to white tea’s relatively unprocessed nature, many of the original enzymes and polyphenols are preserved. These active compounds enable white teas to achieve certain bio-chemical transition more effectively after its processing. It is believed the increase of the flavonoid level is due to certain structural changes of certain polyphenols after a white tea is processed.

It has also been noticed that with a tea’s aging, a substantial amount of Catechin (major part of the polyphenols and main cause of the tea bitter taste and rough texture) converts into Theaflavins (responsible for a tea’s yellow colour and brightness of the brew).

Amino acid in teas is largely responsible for its refreshing taste (甘 in Chinese). As shown in the table, the short term change of the Amino acid is minimum, but there is a significant drop in its level in the 20 years white tea. This is the main reason that the aged white tea is not as refreshing as a seasonal one.

A comparison of aged white tea vs seasonal white tea from consumer point of view

 

	Seasonal white tea	Aged white tea
Colour	Light	Deep yellow
Aroma / flavour	Floral and refreshing	Nutty or date flavour
Texture	Relatively sharper	Smooth
Caffeine level		Relatively lower
Health properties		Relatively more potent

Chinese wisdom: 

This is what the Chinese say about their white teas: for the first year it is a tea, the third year it is a medicine and after seven years it becomes a treasure.