India's 'blue gold' starts a new drinks industry

His 10-acre farm in Kandukur is on the Deccan Plateau, which covers a large part of southern and central India. There he grows tomatoes, peanuts and corn.

But in 2010 he was approached by traders looking for a very different crop - the cactus agave americana.

For him and his fellow farmers the agave cactus was just a "stubborn, valueless weed" - planted as fencing to keep wild animals off their crops.

But it is also part of the family of agave plants that feed the $15bn (£11bn) global market for tequila and mezcal.

In Mexico, blue agave is farmed in the state of Jalisco to supply the tequila industry. Only plants from select areas of Jalisco can be used to make tequila.

Unlike in Mexico, where vast plantations dominate the landscape, nobody grows agave commercially in India - at least not yet.

Instead, Indian farmers and entrepreneurs collect and process agave that grows wild.

For some, like Venkatesh, it's a welcome source of extra income - earning it the name "blue gold".

These days Venkatesh ranges across an area of 100km (60 miles), co-ordinating villagers and farmers.

"By combining the yields of multiple farms, I ensure a steady, high-volume supply that distilleries are willing to pay a premium for," he says.

The most important part of the plant is the heart, known as the piña because it resembles a giant pineapple.

Skilled workers reveal the heart by chopping off the spiky leaves. But getting the timing of the harvest right is crucial.