The strength of the roast aroma is dependent on processing condi tions and is greater in pan-fired tea than in Sen-cha tea. The char- acteristic aroma is largely produced by pyrroles and pyrazines, which are formed during pan-firing or drying by reaction between nes, it the the Maillard intermediate products, a dicarbonyls and free amino used acids through Strecker degradation. In some types of tea(Gyokuro strong and Ceremony dimethylsulphide, produced by degradation of S. methyl methionine is also an aroma impact compound.