The dictionary defines ‘gush’ as to

1. to express oneself extravagantly or emotionally; talk effusively:

Which is generally considered a positive thing. However, in sparkling wine, a second important definition is:

2. to flow out or issue suddenly, copiously, or forcibly, as a fluid from confinement:

Very much a negative aspect in the world of sparkling wine.

A gushing wine is a wine that tends to erupt when opened, causing waste and much consternation.

Rathfinny Sparkling Ice Bucket

One of the leading causes of gushing is the presence of small crystals of potassium bitartrate (also known as cream of tartar) which naturally occur in grapes and can appear in the wine. These tend occur more frequently when the wine is at low temperatures and so it is often called a “cold instability”.

Each of these crystals acts as a nucleation site for bubbles of carbon dioxide on the normal smooth glass surface of the bottle. So, the more crystals, the more bubbles form and hence gushing occurs.

Winery Tanks

Over the years there have been many stabilisation strategies available to winemakers to decrease the risk of this instability. Winemakers often remove bitartrate from the wine, by leaving the wine to ‘overwinter’ at sub-zero temperatures or cooling the wine using modern refrigeration. Alternatively, wineries can use additives to stop crystals from forming.

Electrodialysis

At Rathfinny, we use a relatively new technique known as electrodialysis, which provided a high-quality solution to this age-old problem.  With electrodialysis, the wine is sent through a specific set of charged membranes, which remove the potassium, calcium and bitartrate ions which would form crystals while leaving everything else in the wine untouched. We find this the best way to reduce the risk of gushing while preserving the qualities found in our Sussex Sparkling wine.

So, thanks to this technique you can enjoy Rathfinny Estate wine with precisely the correct amount of fizz. Now that is something to gush about!