The aroma of Pu-erh tea is primarily determined by the following four factors:

1. The aroma of tea depends on its precursor substances.

Precursor substances mainly include terpenes, aromatic hydrocarbons and their oxides, carotenoids, amino acids, sugars, and enzymes necessary for aroma formation during processing. The variety and quantity of these substances form the material basis for tea aroma. Factors influencing these substances include tea plant variety, regional differences, temperature, humidity, light intensity, seasonal changes, growing environment, soil conditions, and leaf maturity. For example, Assamica and Sinensis varieties, Nannuo tea region versus Bulang tea region, Pasha versus Bancha, normal buds versus purple buds (green buds contain higher volatile oils than purple buds).

2. The impact of processing on tea aroma.

A. Different processing methods result in distinct aromas.

For example, Pu-erh tea, Moonlight White, and Classical Beauty made from the same tea garden in Jingmai exhibit significant differences in aroma.

B. Variations in processing (temperature, heating duration, withering time, drying method, drying temperature) also affect aroma.

For example, differences in fixation (temperature, time) lead to noticeable aroma variations: over-fixation (similar to the bean-like aroma of green tea), under-fixation (grassy aroma of raw tea), and proper fixation (fresh fragrance/new tea aroma). This is because under-fixation retains excessive cis-3-hexenol (with a strong grassy scent), which can transform into n-hexanol under enzymatic or thermal action or isomerize into trans-3-hexenol (fresh fragrance/new tea aroma).

C. Formation of new aromas during processing.

Vitamin A precursors—carotenoids—oxidize under enzymatic action and air exposure, forming new tea aroma compounds.

3. The influence of storage conditions on tea aroma.

Tea leaves are highly absorbent and prone to picking up odors. For Pu-erh tea, temperature, humidity, and foreign odors greatly impact its aroma. Organic compounds like polyphenols, amino acids, lipids, and aromatic substances easily oxidize in the presence of oxygen. Different storage conditions determine the direction of these aromatic changes.

For example, high temperature and humidity, low temperature and low humidity, high temperature and low humidity, and low temperature and high humidity have varying effects on tea aroma (under high temperature and oxygen, lipids hydrolyze, producing excessive free fatty acids). Ventilation versus sealed storage also yields different aroma outcomes.

4. The impact of brewing methods on tea aroma.

A pleasant aroma enhances the tea experience. The flavor and aroma of tea are its essence, reflecting differences in fresh leaves, processing, and storage.

Related link: Benefits of Golden Pearl Pu-erh