ISO 3103 is a standard published by the International Organization for Standardization (commonly referred to as ISO), specifying a standardized method for brewing tea, possibly sampled by the standardized methods described in ISO 1839. It was originally laid down in 1980 as BS 6008:1980 by the British Standards Institution. It was produced by ISO Technical Committee 34 (Food products), Sub-Committee 8 (Tea).
The abstract states the following:
The method consists in extracting of soluble substances in dried tea leaf, contained 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.
This standard is not meant to define the proper method for brewing tea intended for general consumption, but rather to document a tea brewing procedure where meaningful sensory comparisons can be made. An example of such a test would be a taste-test to establish which blend of teas to choose for a particular brand or basic label in order to maintain a consistent tasting brewed drink from harvest to harvest.
A revised standard is currently under development as ISO/NP 3103.
To maintain consistent results, the following are recommendations given by the standard:
Nowhere, however, is there mention of the ritual of warming the pot, central to the mystical British Tea Ceremony.
The member body of the following country expressed disapproval of the document on technical grounds: Ireland