Once the yeast has collected in a compact plug in the neck of the bottle we remove it using a process call disgorging.
In order to keep the yeast where it is during the disgorging process we submerse the neck of the bottles in liquid glycol at -25°C for 10 minutes to freeze the yeast plug. Once frozen, the bottles are the turned horizontally and placed in the disgorging line where the cap and bidule are removed.
Using the pressure inside the bottle the frozen yeast plug is forced out of the bottle leaving a clear liquid behind. In a split second a leaver within the machine comes down onto the top of the bottle to retain the pressure. Here is our video showing the process in action:
In sparkling wine production the dosage, a mixture of base wine and sugar is typically added to determine the sweetness of the wine. When disgorging our beer we simply use the bases beer without sugar as a dosage to top the bottles up to the correct level.
Once the correct level is achieved the bottles are ready to be corked, caged and dressed.
Thanks to Alex and James from Bolney Wine Estates who help with the filming of the videos.