Teas are classified as decaffeinated when their caffeine content does not surpass 0.4% by dry weight, equating to roughly 4 mg of caffeine per 170 ml serving.Decaffeination involves removing caffeine from tea. Presently, common methods for decaffeinating black tea include solvent-based extraction using ethyl acetate or methylene chloride, as well as extraction using supercritical (solid) carbon dioxide. All three techniques effectively extract caffeine while preserving the tea’s quality.