When buying a bottled English ale, look for the magic words bottle conditioned
on the label.
What you are buying is a superior product: real ale
in a bottle.
With ordinary bottled beers, the yeast is killed by pasteurisation and filtered out, and
carbon dioxide is added. With a bottle conditioned beer, live yeast is left in, and some
sugar is added for secondary fermentation in the bottle.
A word or warning: Be careful how you keep a bottle of conditioned beer.
Firstly, the beer needs time to mature, and the secondary fermentation process to work.
If you serve a bottle conditioned beer too early (too young), it will be flat. Unless you are in a tropical climate, you want to keep a bottle conditioned beer outside the refrigerator (but it's OK to chill it before serving), as the yeast likes 10-20oC. Too warm, and the beer will condition too rapidly and turn to vinegar.
Secondly, careful how you pour, as the beer contains sediment in the bottom, which
you don't want to drink. Though some people deliberately drink the sediment for its
Outside the United Kingdom, bottle conditioned beers may be difficult to obtain.
Nevertheless, here are a few brands to look out for. ABV stands for Alcohol by volume.