First milk came in glass bottles, then there were polybottles and now its available in the eco pak, launched by Waitrose this week.
The supermarket chain will launch the eco pak in 21 stores, and customers will be able to buy a reusable milk jug with their choice of Calon Wen organic milk.
Should the paks replace polybottles completely, it could reduce the amount of plastic used each year by nearly 100,000 tonnes, the supermarket said.
Britons consume around 180 million pints of milk a week, of which at least two-thirds is sold in plastic bottles.
Calon Wen, a small Welsh organic farmers co-operative that came up with the initiative, said it hoped the trial might go nationwide within six months. Waitrose will sell the one-litre pack for 91p and the plastic jugs will cost £1.99.