Usually different brands of tea powder or tea leaves (shredded leaves) are used, which gives the product its specific flavour and characteristics. In most cases the tea extraction and filtration thereof is carried out hot at 85°C - 95°C.
With Filtrox process the extraction of the tea powder or tea leaves happens in the filter system and special attention is given to the time/temperature relationship. Prolonged heat treatment leads to excessive extraction of tannic compounds which makes the tea bitter and affects the final product. In the production of "RDT", various additives are used such as sugar, acid, flavouring, colouring, etc. which are added after the product has been cooled down. In such cases an additional filtration step may be required prior to packaging.