ISO/TC 34/SC 8 - Tea

This document contains information regarding the tea cultivation, manufacture (including processing and grinding) and sensory analysis of the tea referred to as “matcha tea” in international trade. It provides an internationally agreed definition of matcha tea based on the plant source, cultivation and production methods used. These are important for the physical, chemical and sensory characteristics of matcha tea. It does not apply to flavoured matcha tea, blended matcha tea, or decaffeinated or soluble extracts of matcha tea. NOTE Images of matcha tea and the tencha tea leaf are given in Annex A. Images of the cultivation and processing of the tencha tea leaf are given in Annex B.

This document specifies the requirements for instant tea in solid form. This document does not apply to: a) instant tea containing non-tea carbohydrates as bulking or filling agents (normally referred to as “filled instant tea”); b) preparations of instant tea containing added aromatic material unless these instant teas are derived exclusively from the plant Camellia sinensis; c) decaffeinated instant tea; d) instant tea derived from other forms of tea including herbal teas or infusions.

This document specifies a high performance liquid chromatography (HPLC) or ultra-high performance liquid chromatography (UHPLC) method for the determination of content of the four major theaflavins of tea. It is applicable to both leaf and instant black and oolong teas. The method is currently not validated for ready-to-drink (RTD) beverages.

This document defines terms for classifying and assessing green tea for commerce.

This document specifies a method for the preparation of a liquor of tea for use in sensory tests, by means of infusing the leaf.

ISO 19563:2016 specifies a high-performance liquid chromatographic (HPLC) method for the determination of theanine content in tea (Camellia sinensis). It is applicable to both tea and instant tea samples. Separation of L- and D-theanine is not possible using this method; however, the L-enantiomer is the major form in tea.

ISO/TR 12591:2013 contains information regarding the manufacture and chemical analysis of the tea referred to as white tea in international trade. It provides an internationally agreed definition of white tea based on the plant source and production methods used.

ISO 11287:2011 specifies the parts of a named plant that are suitable for making green tea for consumption as a beverage and the chemical requirements for green tea that are used to indicate that tea from that source has been produced in accordance with good production practice. ISO 11287:2011 also specifies the packing and marking requirements for green tea in containers. ISO 11287:2011 is not applicable to green tea subject to further processing such as decaffeination and further roasting.

ISO 3720:2011 specifies the parts of a named plant that are suitable for making black tea for consumption as a beverage and the chemical requirements for black tea that are used to indicate that tea from that source has been produced in accordance with good production practice. ISO 3720:2011 also specifies the packing and marking requirements for black tea in containers. ISO 3720:2011 is not applicable to scented or decaffeinated black tea.

ISO 14502-1:2005 specifies a method for the determination of the total polyphenol content of leaf teas and instant teas by a colorimetric assay using Folin-Ciocalteu phenol reagent. It is applicable to both green and black tea products.

ISO 14502-2:2005 specifies a high-performance liquid chromatographic (HPLC) method for the determination of the total catechin content of tea from the summation of the individual catechins. It is applicable to both leaf and instant green tea, and with precision limitations to black tea. Gallic acid and caffeine can also be determined by this method, as can theogallin and theaflavins.

ISO 11286:2004 specifies a method for the classification of grades of tea according to an analysis of their particle size. It is not applicable to large, leafy grades of tea. This method may not be suitable for blends of tea.

This International Standard specifies a method for the determination by high-performance liquid chromatography (HPLC) of the caffeine content of teas and instant teas. It is applicable to green tea, black tea and decaffeinated tea products.

This International Standard specifies a method for the determination of crude fibre content in tea.

This part of ISO 9884 specifies requirements and tests to determine the suitability of sacks for the palletized and containerized transport of tea on standard pallets of standard unit load size in standard containers (see ISO 9884-1).

Specifies the materials, construction and dimensions of a reference sack suitable for the palletized and containerized transport of tea.

The principle of the method specified is extraction of soluble matter from a test portion by boiling water under reflux, filtration, washing, drying and weighing of the hot-water-insoluble residue, calculation of the water extract.

The method consists in extractiing of the total ash with hot water, filtration through ashless filter paper, ignition and weighing of the residue to determine the insoluble ash; calculation of the soluble ash by difference.

The method consists in destructing of organic matter by heating at 525 +/- 25 degrees centigrade to constant mass using a furnace, capable of being controlled.

The method consists in treating of the total ash (obtained as described in ISO 1575) with hydrochloric acid solution, filtrating, igniting and weighing of the residue.

The specified methods apply to sampling from containers of all sizes. Separate methods are described for sampling at the point of manufacture, sampling at susequent stages in the distribution chain and sampling of retail packs. In addition, different procedures or special precautions are specified depending on wether the samples are to be used for examination of particle characteristics (for example bulk density, flowability, particle size) or compositional characteristics (for example moisture content, ash).

The method for the determination of the free-flow bulk density consists in pouring a sample from a specified funnel into a specified receptacle of known volume, and weighing the contents of the receptacle. The determination of the compacted bulk density consists in determining of the volume of a given mass of the product after a fixed number of taps (usually 100) in a jogging volumeter.

The method consists in heating a test portion in an oven at 103 +/-2 degrees centigrade, to constant mass.

The method consists in grinding of the sample, and determination of the dry matter content of the ground sample by heating a test portion in an oven at 103 +/-2 degrees centigrade to constant mass.

Applies to sampling from containers of all sizes. First are given definitions of relevant terms, followed by a description of apparatus, general information, sampling from containers, packaging, labelling and dispatch of samples, and the sampling report.

The method consists in titrating of the filtrate from the determination of water-soluble ash, whith standard hydrochloric acid solution, using methyl orange as indicator.

The method specified is based on extracting the caffeine from a test portion with water at 90 °C in the presence of magnesium oxide, filtration followed by determination of the caffeine content by HPLC with UV detection. Applies to teas and instant teas with a caffeine content of greater than 0,3 % (m/m).

Specification of the parts of the plant that are suitable for making black tea for consumption as a beverage and the chemical requirements that are used to indicate a good product. Further specification of the packing and marking requirements.

The method consists in extracting of soluble substances in dried tea leaf, containing in a porcelain or earthenware pot, by means of freshly boiling water, pouring of the liquor into a white porcelain or earthenware bowl, examination of the organoleptic properties of the infused leaf, and of the liquor with or without milk or both.