Why Is Bottled Beer fizzier than Cask?

Beer bottles

Why is it that when I order a real ale in a pub from a cask, it comes out quite smooth, but when I buy the exact same product in a supermarket, it’s fizzy?

Mystery Hour Question

Why is it that when I order a real ale in a pub from a cask, it comes out quite smooth, but when I buy the exact same product in a supermarket, it’s fizzy? Jamie, South Woodford

Answer

Name: Paul, Hampton Court

Qualification: Spent 15 years in a brewery laboratory testing beer.

Answer: At the brewery, they add more CO2 because TET bottles actually lose gas through them over time, and they don’t differentiate between batches for plastic & glass bottles and cans. I’m talking about euro-fizz beers mainly – lagers.

Name: Charles, Stockport

Qualification: Member of the campaign for real ale for about 40 years

Answer: With cask conditioned beer, there’s only a small amount of secondary fermentation that takes place, and it doesn’t really pressurize the cask, so when you pull it off, there’s a bit of sparkle but that’s about it. With bottled beers, even bottle-conditioned beers, there’s a lot more carbon dioxide pressure – nothing to do with the fact it was plastic because they were like that before they used plastic bottles.