Making sparkling wine is the technical end of the spectrum for winemakers, comparable to baking in the world of chefing. There are multiple critical steps that must be done in just the right manner for the creation and evolution of a single bottle, each of which will steer the style, flavours and quality. With a cooler vintage in 2019, it made sense to produce English sparkling wine, the pH, sugar levels, acidity, and aromatic profile of the grapes were all screaming fizz. So rather than pushing the grapes in a specific wine direction, perhaps a square peg in a round hole, we took on the challenge of producing our very own in-house London made bubbles.
A perfect bunch of Pinot meunier in the vineyard one week before harvest.
Late in the harvest season, specifically in the last week of October, we harvested some beautiful Pinot Meunier grapes grown near Canterbury. Once in the cellar, the grapes were whole bunch pressed in our small 1-tonne pneumatic press. When making sparkling wine pressing is conducted very precisely. The initial juice running from the grapes is a little dusty/muddy in appearance, this juice is sent to a secondary tank. When the juice starts to flow clean, bright and beautiful, the press lines are changed to the primary tank. For our wine this was roughly 50-60% of the volume and included the most lightly pressed, lowest extracted juice, the heart of the wine. Once a target volume was reached, we once again directed the juice to the second tank. Finally, as the pressures increased during the press cycle the most highly extracted juice, the harder pressings, were kept separate from the previous two tanks.
These different tanks were all fermented separately. For our sparkling Meunier, the harder pressings were fermented and aged in used oak barrels which we sourced from Domaine Chavy-Chouet in Puligny Montrachet, Burgundy. These barrels have been used in the production of Chardonnay for 4 vintages before our wines met them. The ethos behind including barrels was to add a soft micro-oxidation character and bring lightly oaked aromas and sweetness to the mid-palate. The main volume of wine was fermented in a stainless tank, preserving the bright fruity driven aromatic quality of the Pinot Meunier grapes.
The wines then all went through malolactic fermentation, which reduces the malic acid in the wine in favour of lactic acid. In cooler years this is a critical step in the UK as the starting malic content of the juice can be quite high, which results in an aggressive acidity in the final wine. Malo brings a softness to the wine as well as builds some complexity of aromas. The wine was then cold stabilised, which prevents the crystallisation of tartaric acid in the bottle. This step we do the classical way of simply chilling the wine for two weeks at around 1 degree celcius.
At this stage the wines were ready for the seminal process when making traditional method wines, the secondary fermentation. The base wine blend was made up from the different tanks and barrels. 3 days before bottling a sparkling wine yeast culture was prepared, which included specifically selected natural yeast well known to thrive in the high acid, high pressure, cold and low-nutrient world of bottled fermentation. This environment is very difficult, so this choice of yeast is paramount to the success of this fermentation.
Sugar is then added to the wine at a quantity of 24g/L, as this is the amount consumed by the yeast to naturally produce 6 bars of pressure in a single bottle. Anymore and the bottle may explode, too little and the bottles will not be lively enough. At this stage we also added a small amount of bentonite (clay) to the wine, which may sound strange, but will greatly help the future riddling of the bottles. Critically, as sugar concentration graduates to the bottom of the tank the wine must be circulated regularly whilst bottling, so that all the bottles are consistent in pressure.
The prepared yeast culture is then added to the wine, sugar and bentonite, with a small dose of nutrients and vitamins, and off we go into the bottle. The bottles were then capped and laid down. For English Wine it is a requirement the bottles stay this way for a minimum of 9 months.
Following this, the next step for our bubbles will be to riddle the yeast into the neck of the bottles. We will do this the old-school way by hand riddling using wooden frames. The yeast will then removed from the bottle, disgorged, and the sugar levels and wine levels balanced before corking. It will then take around 6 months after corking for the sparkling wines to shine their true potential, in spring 2021.
Our whole team is closely watching the progress in the bottles, we even get a sneaky tasting every now and then which has to be one of the most exciting perks of the job!
