A Mexican student has come to Sussex University to spend four years on a PhD course - studying tequila.

In a move akin to English people heading overseas to learn about roast beef and Yorkshire pudding, Mexican postgraduate Ivan Saldana Oyarzabal aims to get a deeper understanding of the drink.

But the 25-year-old, who is undertaking a doctorate in biology, will not be living every student's dream by spending the day getting plastered. He will be learning more about the plant from which the spirit is made.

Tequila is Mexico's national drink but Ivan, who comes from Guadalajara, 50km from the town of Tequila, said facilities here were far better than those back home.

He is now busy making revolutionary inroads into the make-up of the Agave tequilana plant.

He said: "I love tequila. In Mexico there are forests dedicated to the plant and it is very interesting to be able to investigate it in more detail.

"It is a very traditional drink in Mexico, though it is drunk differently there than it is here. We tend to enjoy it more and drink it slowly before dinner.

"People only drink it like they do in England - when people have tequila slammers and down it - when people have no money and want to get very drunk."

Agave plants thrive in Mexico where conditions such as altitude and climate are perfect for their growth. It takes the plant eight to ten years to mature and be ready for harvesting and distilling.

Ivan said: "They are important plants economically and culturally but their molecular biology has not been investigated that much in the past."

Past research has concentrated on the agave's chemical and industrial properties, in particular how to produce the maximum amount of alcohol and how to use the waste products from tequila production.

Ivan is more interested in its sugar-making capability and although his studies into the plant's make-up are purely for his own interest, the results may aid future production of the drink.

He said: "Almost all agave plants are clones because they are never allowed to develop seeds. Normally they never flower, as the maximum amount of sugar in the plants is just before they flower.

"They also accumulate fructose rather than sucrose, which is unusual."

Eighteen Agave specimens have been especially shipped over from Mexico for the project and Ivan lamented the quality of tequila in England.

He said: "Brighton is a really nice place but the quality of the tequila in England is poor.

"It tends to be of the commercial type and so I try to get friends to bring bottles back when they go abroad or when they come back from Mexico."

The best part of the course for Ivan is being able to get back to the grass roots.

He said: "My favourite bit is being able to think about nature and, of course, I also enjoy figuring out how these plants work."

Ivan, whose research is being funded by the Mexican Council for Science and Technology, said he could not decide whether Mexicans or Brightonians were the biggest drinkers.

Tequila was first produced commercially thanks to a mix of indigenous Indian and Spanish technology in Mexico more than 200 years ago.