The bio-dependent, sustainably sourced wood fibre has the additional advantage of insulative Qualities to keep beer colder for longer, compared to cans or glass bottles. The inner lining of such bottles is often made from a skinny layer of biodegradable plastic to make sure the bottles keep on being leak-proof. https://www.tumblr.com/sustainablemilkcartons/776508172998443008/free-water-advertising-gabletop-paks?source=share