‘Outrageous’ tea recipe involving pinch of salt draws US embassy comment

American chemist inspires moment of diplomatic levity with controversial brewing suggestions

The special relationship between two G7 countries has possibly been imperilled by an American scientist's claim that Britain's favoured brew requires a pinch of salt.

The international incident was triggered when a scientist from the US claimed to have found the recipe for a perfect cuppa. The secret, according to Michelle Francl, a professor of chemistry at Bryn Mawr College, is a pinch of salt - and energetic squeezing of the teabag.

Adding a pinch of salt - the sodium ion in salt blocks the chemical mechanism that makes tea taste bitter.

Steeping teabags quickly but with plenty of dunking and squeezing - to reduce the sour-tasting tannins created by caffeine dissolving slowly in water.

Decaffeinated tea can be made by steeping a teabag for 30 seconds, removing it and discarding the liquid, then adding fresh water and rebrewing for five minutes.

A small squeeze of lemon juice can remove the scum" that sometimes appears on the surface of the drink, which is formed from chemical elements in the tea and water.

The aroma of tea is almost as important as the taste - so when drinking from a takeaway cup, it's best to remove the lid.