With its complex taste profile and aromatic qualities, it is no surprise that tea is the second most consumed beverage in the world following water. Laden with anti- oxidants and natural compounds, the magical properties of tea – black, green, or Oolong -- find its source in the leaves of the plant Camellia sinensis. Oxidation levels of the leaves are what grants these different types of tea their respective unique tastes.

Oolong (Wu-lung) tea is a semi-oxidized tea, the mention of which arose around 400 years ago. Made from the combination of words “black” and “dragon”, Oolong tea boasts of a light, fruity flavor and a honey-like mild aftertaste. Although originated in China, the cultivation of Oolong tea was initiated in the terrains of Taiwan in the 19th century and quickly rose to be one of the leading export commodities of the country. However, the wonders and mysticism of a good cup of Taiwanese Oolong tea are backed by science – specifically the effects of elevation and geographical location of the tea. Originally derived from wine production but extending to tea, the concept of “terroir” entails that the quality and taste of tea is impacted by the area where its grown. The soil composition, weather conditions, elevation, and local ecosystem have a profound impact in curating the distinct flavor profiles.

An island located near South-eastern coast of China, the sub-tropical climate of Taiwan in combination with its mountain-rich topography provides the perfect blend of conditions for the growth and cultivation of high-quality tea.

Aligning with the concept of terroir, elevation of the tea farms is crucial for the development of distinct flavor profiles. Broadly, the tea originating from varied altitudes can be classified as follows:

1. Low-elevation Oolong tea (flat): Typically located about 500-1000 meters above sea level, low-elevation tea farms experience a warmer, less misty climate. Tea harvested from this region are higher in astringency and bitterness. They are earthier and provide a stronger after-taste. Oolong tea cultivated in the Dong Ding (Frozen Peak) area located 600-800 meters above sea level in Nantou county, is rich in the bold characteristics associated with low-elevation farmlands.
2. Mid-elevation Oolong tea (mountain): Located 1000-1500 meters above sea level, the tea cultivated in these hillier terrains experience a slightly cooler temperature combined with increased fog cover. The taste profile of the tea speaks of a perfect blend between the astringency associated with low- elevation areas and sweetness associated with high-elevation areas. Tea grown in the mid-altitude regions of Li Shan (Li Mountain or Pear Mountain) ranges withhold these characteristics. The Yushan high mountain Oolong tea is an example of a mid-elevation tea grown at an elevation of 1400 meters.
3. High-elevation Oolong tea (alpine): With altitude upwards of 1500 meters, high-elevation tea is embraced by chillier weather, thick mist and cloud cover. The stark contrast in the day-time and night-time temperatures lead to an overall slower growth. The slower growth, in turn, facilitates the accumulation of richer flavor. These alpine Oolong teas or gao shan (high mountain) teas are characterized by smooth, sweet flavor attributed to higher levels of theanine with decreased levels of catechins responsible for bitterness. The leaves are lush, green, with higher pectin levels. Some of the most well-known mountain ranges that house the high-elevation Oolong teas are the Alishan ranges, Li Shan ranges, Shanlixin, and Dayuling mountain regions. Located in central Taiwan, the Alishan mountain ranges include 18 mountains with the tea cultivated from this area being high on floral notes and sweetness. The Li Shan range is located in north Taiwan and tea harvested from this range is associated with a creamier, more buttery flavour. The Dayuling Oolong, grown at altitudes higher than 2500 meters is extremely sought after due to its limited production.

As the impact of elevation on tea gained prominence, so did the scientific studies to unravel this mystery. The differences in temperature and light bring about changes within the chemical composition of the tea. Catechin biosynthesis is altered at higher elevations, thus reducing the bitterness. Moreover, there is an increment of amino acid content, specifically L-theanine. Other than impacting taste, L-theanine has been documented to improve quality of sleep and reduces signs of anxiety. Due to the intense cloud cover, the light intensity is reduced which can further impact the production of secondary metabolites, thus, affecting the overall properties of the tea.

Currently, Taiwan has nearly 20,000 hectares of farms dedicated to tea production, churning out a whopping 20,000 tons of tea annually. Tea as a beverage is intricately woven into the cultural fabric of Taiwan and integrated heavily into the daily lives of the people.

So, the next time you pick up a cup of steaming hot Taiwanese Oolong tea, make sure to take a moment and savor its mountainous origins.