The Perfect Cup of Tea part 1 (ISO 3103:1980)


ISO teacupEverybody wants to brew the perfect cup of tea. Well, except those silly coffee drinkers, but we usually ignore them on our tea blogs, don’t we?

I’ve made it clear on this blog before that I’m not a big fan of tea Nazis, nor do I necessarily agree with folks like George Orwell about what constitutes a “nice cup of tea.” There are many, however, that believe the perfect cup is not subjective and is not open to debate.

Some organizations that feel they have the secret well in hand have released official documents describing the process, although I suppose that means it’s not a secret anymore. I’ve recently looked over a couple of those documents that I’d like to share. Today, we’ll look at a lovely document called ISO 3103:1980.

ISO 3103: Tea — Preparation of liquor for use in sensory tests

The International Organization for Standardization (ISO) has developed standards for everything from electronics to language and currency codes to quality control management. They also have a food safety management group that has taken it upon themselves to set the standard for preparing a cup of tea.

The standard itself (ISO 3103:1980) is available in the U.S. for the low, low price of $53.00 (less for members) from ANSI, the American ISO member (buy it here). The official description is

“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.”

(I have to confess, word geek that I am, that I had to look up the word “organoleptic.” I will definitely be using this word in the future!)

For those who don’t wish to pony up fifty bucks for the official standards document, there is a summary on Wikipedia. In keeping with their Creative Commons Attribution-ShareAlike License, I shall copy the details here and save you the trouble of clicking on the link. I’m changing their bullet points to a numbered list for easy reference. These numbers don’t appear in their document.

  1. 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.
  2. If a large pot is used, it should hold a maximum of 310 ml (±8 ml) and must weigh 200 g (±10 g).
  3. If a small pot is used, it should hold a maximum of 150 ml (±4 ml) and must weigh 118 g (±10 g).
  4. 2 grams of tea (measured to ±2% accuracy) per 100 ml boiling water is placed into the pot.
  5. Freshly boiling water is poured into the pot to within 4–6 mm of the brim. Allow 20 seconds for water to cool.
  6. The water should be similar to the drinking water where the tea will be consumed
  7. Brewing time is six minutes.
  8. The brewed tea is then poured into a white porcelain or glazed earthenware bowl.
  9. If a large bowl is used, it must have a capacity of 380 ml and weigh 200 g (±20 g)
  10. If a small bowl is used, it must have a capacity of 200 ml and weigh 105 g (±20 g)
  11. If the test involves milk, then it is added before pouring the infused tea.
  12. Milk added after the pouring of tea is best tasted when the liquid is between 65 – 80 °C.
  13. 5 ml of milk for the large bowl, or 2.5 ml for the small bowl, is used.

Clearly, this standard is designed for comparative testing of tea, not for consumption. In my humble opinion, this standard would ruin the majority of the teas that I drink. The water temperature (paragraph 5) would make a bitter mess out of most white and green teas, and the steep time (paragraph 7) would destroy most of the black and pu-erh teas I drink (and the oolongs and greens, for that matter).

It surprises me not in the slightest that British version of this work (called, appropriately enough, BS-6008) received the Ig Nobel Prize in 1999.

In part 2 of this series, we’ll take a peek at what the Royal Society of Chemistry has to say.

About Gary D. Robson

Gary Robson: Author, tea guy, and general manager of the Billings Bookstore Cooperative. I've written books and articles on a zillion different subjects, but everyone knows me for my "Who Pooped in the Park?" books.

Posted on 24 April 2013, in Tea Biz and tagged , , , , , , , , , , . Bookmark the permalink. 1 Comment.

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