The new 50cl bottle for The Bitter, Explorer and Broadside weighs less than 300g - which means it uses 34 per cent less glass than Adnams' original glass bottle.
Marketing manager Ed Hume said: "Adnams is committed to sustainable business and we are always looking for ways to improve our business practice. The environmental and cost savings of the new bottle are significant. Using a lighter weight bottle will not only lessen the use of glass, but will also result in fewer carbon emissions from the manufacturing process, which will in turn mean lower fuel usage due to lighter transportation."
Adnams has been working hard on going green for some time. Last year it opened an eco-friendly distribution centre outside its home town of Southwold, and a new brewery, due to open this spring, will be more energy efficient.
The brewer has also been working with the University of East Anglia's carbon reduction team to do more to cut its carbon footprint across the business.