Yes cans are better keeping oxygen out ,keeping it out during canning is a bugger Bottle conditioning still best— John Keeling (@FullersJohn) July 28, 2015
So there you have it: the Fullers head brewer shares the misgivings a lot of people have already expressed about the craft can fad. His counterpart at Thornbridge has said that he's "unconvinced that the canners towards the lower end of the market are capable of sealing the can without potentially picking up detrimental levels of dissolved oxygen".
John Keeling clearly isn't totally against canning. Fullers have been using them for many years, particularly for export. I spotted 500ml cans of Pride, ESB and London Porter in a Conad supermarket in Italy recently. But then a brewery the size of Fullers will have access to the very best canning lines. Others however, who use bottom of the range kit, might see their beer exposed to too much oxygen for too long during the packaging process. It's obvious that the surface area of the beer exposed to the air when you seal a can is far greater than that in bottle, with a narrow neck.
I'm an investor, and have an ongoing involvement, in a London microbrewery. I was shown the quote when we were approached by a company doing a mobile canning service. They drive up to your brewery in a lorry and package the beer for you on their kit in a trailer. It was bloody expensive and seems a bit dicey, so we gave it a miss, but it's proven popular with others. I won't name names, but you can tell who's used the service because the can won't be printed: the label will have been applied to the bare metal. Probably best to avoid those.
Went to see that lad Frankie Boyle doing his first Edinburgh preview in Soho last night. He was basically just reading jokes from a piece of paper to gauge reaction. A pub-related one about Nigel Farage: asked audience if we remembered when Farage got set on by angry SNP supporters in Edinburgh, and hid in a pub. "Hiding from Scottish people in a pub? That's like dressing up as a zebra to escape from a lion".