Over the course of four days, it's all hands on deck at Black Chalk, as we bottle approximately 80,000 bottles of sparkling wine. The creation of sparkling wine is a delicate dance of science and art, and one of the pivotal steps in this process is "tirage." This French term refers to the crucial phase where the base wine is bottled and undergoes a secondary fermentation, bringing our bubbles to life!
Tirage is an intricate and complex process and highlights the craftsmanship behind our sparkling wines. The artistry in tirage managagement ensures that each bottle of sparkling wine we deliver is a consistent and delicious, from the first pop of the cork to the last sip! Let's take a look at the process in more detail...
In sparkling wine production, Tirage (often referred to as "bottle fermentation" or "secondary fermentation") is the step where a mixture of sugar and yeast—called the "liqueur de tirage" is added to the base wine. This initiates a second fermentation within the crown capped bottle, producing carbon dioxide and creating our wine's signature bubbles.
Preparing the Base Wine The journey begins months before bottled, with the creation of our base wines. These are a blend of the 34 different grape clone combinations we grow in our vineyards. This still wine is fermented and clarified before being prepared for tirage. The base wine's quality and characteristics are crucial as they form the foundation of the final product. You can read more about how we create our base wines here.
Creating the Liqueur de Tirage
In the days leading up to bottling, our winemaking team will start to make the 'liqueur de tirage'. this is a carefully measured blend of sugar, yeast, and sometimes yeast nutrients - think of it like a sourdough starter...The amount of sugar and yeast added is critical, as it determines the level of carbonation in the final wine. Once the bottling line is set up, this mixture is thoroughly integrated with the base wines whilst they are in the tanks.
Bottling and Sealing The base wine, now infused with the liqueur de tirage, is then pumped out of the tank and into the bottling line. Each bottle is placed onto the bottling line and then automatically filled with the infused base wine. The bottle is then sealed with a crown cap, similar to those used on beer bottles. This secure closure is essential to withstand the pressure which builds-up during the secondary fermentation inside the bottle.
Secondary Fermentation
The bottles are then taken from the bottling line and packed horizontally into cages and left in a cool, dark environment. Over several weeks, the yeast consumes the added sugar from the liquer do tirage, which produces alcohol and carbon dioxide. The CO2, trapped in the bottle, dissolves into the wine, and it's this that creates the bubbles that define sparkling wine!
It'll be a minimum of 18 months before these wines are then riddled and disgorged. Some of our wines spend over 2 years resting on lees before being disgorged, with a further minimum 6 months aging on cork but that's a blog post for another time...
Once all the bottles are packed and stacked the bottling line can be dismantled and everyone gets to enjoy a celebratory beer! Four days, 80,0000
bottles, one amazing but tired team! Until next time!
