Auto vent plugg

Simply push this peg into the shive / spile hole after you've initially venting the cask. The peg will only allow the volume of air to enter the cask as to the volume of beer being taken out of the cask ( 1 pint of beer + 1 volumetric pint of air). By this action, none of the vital condition can escape and no extra air can enter the cask. It is the loss of condition and air that increases the speed of the ale becoming unpalatable.