Abstract:To study alterations in organic acid components of Tieguanyin tea during aging process and to establish regulatory systems concerning aging quality of old Tieguanyin tea，concentrations of 10 organic acids in fresh Tieguanyin tea and 6 aged Tieguanyin teas（aged 6，9，13，18，25 and 30 years）were measured using high performance liquid chromatography.The contribution of each organic acid to sour taste was analyzed using taste activity value（TAV）.The content of the sum of 10 organic acids tended to initially increase and then decrease and level off during ageing；however，the content of organic acids was higher in all aged Tieguanyin teas than in fresh tea.The highest concentration of organic acids occurred in 6-year-old tea，which was 1.77-fold high than that in fresh tea.Lactic acid and succinic acid were the predominant organic acids，accounting for approximately 44.6%-54.5% and 24.8%-37.1% of the 10 organic acids，respectively.Each organic acid，apart from acetic acid and DL-tartaric acid，showed marked fluctuation during the early period of aging，but changes were moderate during later stage.These characteristics explained why aged Tieguanyin teas had a strong sour taste during early aging stages and showed a mellow，not astringent flavor at later stages.The variation in TAV of organic acids showed that succinic acid was the predominant contributor to sour taste at TAV＞1 throughout the aging process.