It’s a Daily Ritual Beloved by Billions. There’s Actually a Rule Book for It. It’s a Delight.

Science The World’s Most Official Cup of Tea An international standard tells us how to brew tea in glorious detail. It has a surprisingly practical purpose. Getty Images Plus Sign up for the Slatest to get the most insightful analysis, criticism, and advice out there, delivered to your inbox daily. For many, a cup of tea is a simple daily ritual, but there’s actually a group of people that takes it a bit more seriously. This is the International Organization for Standardization. An expert body that compiles reference documents for consistency in manufacturing and services, they are the ones making sure the technical specifications for brewing a cuppa exist—and make the world a better place. ISO brings together experts from across the globe to help agree on the proper way all sorts of things should be made or managed. Much of the group’s production of standards, voluntary but widely followed sets of specs, is about as dry as you’d expect. ISO 9000, for example, lays out the basic concepts and vocabulary of quality management. There are also standards for things like the physical dimensions of ID cards. Then there’s ISO 3103, “Tea—Preparation of liquor for use in sensory tests.” First published in 1980 and updated in 2019, it brings the same bureaucratic precision to preparing tea. The aim is to give professional tasters everywhere a repeatable procedure for brewing and comparing cups. For example, the Sri Lanka Tea board has used ISO 3103 in its tasting unit, which assesses tea before auction and export. The standard helps tasters judge the leaves without differences in brewing muddying up the comparison. The ISO subcommittee in charge of tea last convened in September with agenda items including chemical analysis of chlorophyll in matcha tea and a preliminary report on masala chai, which sounds like a true oasis in these turbulent times. It might not be shocking that ISO 3103 is not their only creation. They count 37 standards and 10 working groups that are tasked with responsibilities like issuing tea bag specifications. ISO 3103 doesn’t claim to provide the secret to the perfect cup, but aspires to a consistent cup for people in the tea industry, be it a barista in New York City or a master blender handling the latest harvest in Lipton’s labs—a job that can involve appraising hundreds of different brews a day. “What appears to be a simple question of how to brew tea becomes a technical issue when sensory assessments need to be repeatable across laboratories, companies, countries, and decades,” the ISO subcommittee wrote to me; by controlling the factors that enter the brewing, “differences observed in tasting sessions can be attributed to the tea itself rather than variations in preparation.” Bureaucracy at its most endearing. The standard gained wider recognition in 1999 when its early form won the spoof Ig Nobel Prize in Literature. The prize’s creator wrote that its “hot, steamy prose … epitomises literature, propriety and teatime.” It clearly makes sense to call it a “six-page classic.” The principle underlying the document, we learn, is “Extraction 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.” The standard advises on tea quantity, brewing time (six minutes for black, three to five for different green leaves), and the right way to pour; provides precise reference masses and dimensions for teapots and bowls, as they can affect the temperature profile; and culminates in brief but precise instructions for preparing a sensory assessment report. The standard doesn’t shy away from the debate of adding milk (“black tea only”) before or after the “liquor.” Before wins, “unless this procedure is contrary to the normal practice in the organization concerned,” leaving everyone wondering where organizations with such concerns operate and if they are hiring. Surprisingly, there has been controversy in the past. Ireland has objected to the standard, and experts have speculated that the debate was whether the teapot should be pre-warmed. This precaution against reducing the water temperature is absent from ISO 3103—conspicuously so, in the eyes of some tea aficionados, and particularly Irish ones. Instructions like high temperature and long steeping can sound uncommon, but Suzette “Sooz” Hammond, tea educator in Chicago, explains the logic. “The reason for tasting tea this way in the first place is like purchasing a car,” Hammond told me. “You’d want to test-drive it! We cup the tea in this way to see where the edges come out, what the deep personality is like, what the aroma is like when piping hot and as it cools. Good quality tea will always shine, no matter the brewing.” However, with cupping training not always readily offered, the ISO provides something reassuring: precision, expertise, and sharing. “When people talk about knowledge gatekeeping in a field or trade, this is very much what they’re referring to,” Hammond said. “The ISO laid it all out, with the goal of sharing the knowledge widely.” It doesn’t matter if you are in New York or London or Tokyo—the standard likely helped the professionals who brought it to you to get a nice warm mug of tea just right. Food Research Science Drink