FROM ANCIENT Chinese dynasties to the PG Tips chimps – via Arthur Dent and Mrs Doyle – tea has always been a more complicated business than just dried leaves in boiled water.

Now Irish favourite Lyons Tea is embarking on a four-year process to source all of its tea from farms that are sustainably managed and have a certificate from the Rainforest Alliance to prove it.

Consumer demand for guilt-free tea is behind the push by Lyons and its parent company, global consumer brands giant Unilever, according to Lyons marketing manager Keith Farrell.

Marcel Clement from the Rainforest Alliance suggests another reason. Tea companies are seeking out sustainable farms because they do not want to run out of tea.

Already, half of Lyons’s original blend tea bags, the biggest-selling blend in Ireland, hails from sustainable sources and the company announced this week that all of its brands will have the Rainforest Alliance seal of approval by 2012.

Unilever, which also owns the PG Tips and Lipton brands, buys 12 per cent of the world’s tea.

Although the Rainforest Alliance does not negotiate premiums for its certified farmers, Unilever’s tea-buying costs will rise by about €2 million a year by 2010, as certified farms produce higher-quality tea.

Lyons is backing its “Make Tea Make a Difference” campaign with television advertising featuring a blend of smiling Kenyans and a weary Irish mother destressing over a cup of fully sustainable tea.

However, the Irish no longer drink the highest amount of tea per capita – that honour goes to Japan.