ISO 3103 is a standard published by the International Organization for Standardization, 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, and a revision was published in December, 2019 as ISO/NP 3103. It was produced by ISO Technical Committee 34, Sub-Committee 8. The abstract states the following:
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. The work was the winner of the parodic Ig Nobel Prize for Literaturein 1999.
Details
To maintain consistent results, the following are recommendations given by the standard:
The pot should be white porcelain or glazed earthenware and have a partly serrated edge. It should have a lid that fits loosely inside the pot.
If a large pot is used, it should hold a maximum of 310ml and must weigh 200 g.
If a small pot is used, it should hold a maximum of 150 ml and must weigh 118 g.
2 grams of tea per 100 ml boilingwater is placed into the pot.
Freshly boiling water is poured into the pot to within 4–6 mm of the brim. Allow 20 seconds for water to cool.
The water should be similar to the drinking water where the tea will be consumed.
Brewing time is six minutes.
The brewed tea is then poured into a white porcelain or glazed earthenware bowl.
If a large bowl is used, it must have a capacity of 380 ml and weigh 200 g.
If a small bowl is used, it must have a capacity of 200 ml and weigh 105 g.
If the test involves milk, then it is added before pouring the infused tea unless that is contrary to the organisation's normal practice.
If milk is added after the pouring of tea, it is best added when the liquid is between 65-80°C.
5 ml of milk for the large bowl, or 2.5 ml for the small bowl, is used.
Criticism
The protocol has been criticized for omitting any mention of prewarming the pot. Ireland was the only country to object, and objected on technical grounds.
