Journal of Advances in Biology & Biotechnology

Tea-derived beverages constitute a globally distributed but analytically heterogeneous family extending from minimally transformed leaf infusions to oxidised, post-fermented, powdered, concentrated, ready-to-drink and composite milk- or sugar-containing products. Their common botanical origin can obscure the extent to which cultivar, leaf maturity, manufacturing sequence, extraction conditions, microbial ecology, formulation and storage redefine the beverage actually consumed. This critical narrative review integrates evidence on beverage diversity, chemical architecture, processing-induced transformation and consumption patterns. Literature published from January 2000 to 20 May 2026 was identified through accessible scholarly indexes, bibliographic databases, DOI records and citation chaining, with inclusion governed by verifiable metadata, methodological relevance and direct support for the synthesis. The evidence indicates that the conventional six-tea classification remains useful for production and cultural description but incompletely predicts beverage chemistry. Oxidation, heating and microbial conversion redistribute catechins, polymeric pigments, amino acids, alkaloids, organic acids and volatile compounds, while brewing and formulation determine their transfer, stability and sensory expression. Post-fermented teas and kombucha share microbial transformation but differ fundamentally in substrate, ecology, control points and safety concerns. Ready-to-drink, instant, cold-brew, matcha, milk tea and bubble tea formats widen access and sensory diversity, yet complicate comparison because processing severity, solids intake, sweeteners and matrix interactions are often poorly reported. Consumption evidence confirms broad geographic expansion and product diversification, but most surveys measure cups or beverage categories rather than chemical exposure. The main research need is therefore not another universal ranking of tea types, but interoperable product definitions, process-aware chemical reporting and formulation-sensitive consumption surveillance. A unified approach linking raw material, unit operations, beverage matrix, storage, sensory outcomes and consumption context would improve quality control, cross-study comparability and interpretation of tea-derived beverages as foods rather than undifferentiated carriers of selected bioactives.