What do cask breathers do, and are they allowed as per CAMRA standards?

Cask breathers serve the primary function of maintaining the quality of cask-conditioned beer by ensuring the beer breathes properly through a controlled introduction of CO2 while also protecting it from oxidation. They balance the necessity of allowing cask beer to undergo natural conditioning and prevent it from going flat by replenishing CO2 as the beer is drawn from the cask.

When it comes to the standards set by CAMRA (Campaign for Real Ale), the use of cask breathers is not permitted. CAMRA advocates for traditional cask conditioning methods that maintain the natural carbonation and flavor profiles of the beer, which can be compromised by the use of external gas systems. This focus on traditional methods reflects the organization’s commitment to the characteristics that define cask ales, emphasizing a natural relationship between yeast and the beer’s ingredients.

The other options highlight functions that do not align with the designated capabilities and acceptability of cask breathers within CAMRA regulations, which further cements why the correct answer reflects the prohibition of such devices.