In commercial cider production, most sparkling ciders get their bubbles by way of compressed CO2 gas. This is a great system because it is affordable, fast, and consistent. There is however, another option called bottle (or cask) conditioning.
In the days before stainless steel, compressed gas, and refrigeration, a beer or cider would be put into a sealed barrel or bottle when it still had just a tiny bit of sugar left that the yeast had not yet fermented. Yeast eat sugar to produce alcohol and CO2 and during a normal primary fermentation, that CO2 will simply bubble out the top of whatever container your cider is fermenting in. By sealing the vessel up near the end of fermentation, the cidermaker is able to trap that last little bit of CO2 which will eventually be absorbed by the cider. All of that naturally produced carbonation stays put until you open that bottle or the bartender hammers a faucet in to that cask.
At Potter’s we have chosen to use bottle conditioning for certain ciders to highlight the character of the specific yeast used. All of our Belgian themed ciders are bottle conditioned including Farmhouse Saison, The Haven, and the newly released Ginger & Honey. RVA Yeast Labs in Richmond has harvested these yeasts from some of the great Belgian breweries and grown them on a gluten free medium for us. We used wildflower honey from our neighbors at Sourwood Farm for bottle conditioning on the Ginger & Honey. While the honey ferments out to have no residual sugar in the cider, the floral nose it imparts is unmistakable.
Another series of our ciders in which we employ bottle conditioning is our Brettanomyces (or brett for short) series. Brett is a wild yeast strain found almost everywhere in the world. While eschewed by most winemakers, cidermakers, and brewers, a select few producers have learned how to really harness the unpredictable character of this yeast. It is best known for the funky, fruity nose it imparts to Belgian lambics and those beers were our direct inspiration for the Raspberry, Blackberry and Peach Brett ciders. We start with 100% Goldrush apples and ferment the juice in oak barrels. We let the cider age through winter. Once the temperatures start to rise outside, we introduce brettanomyces to the barrels along with a dose of locally grown raspberries (or peaches or blackberries) and let the cider ferment on the fruit for a few months. Again, we bottle condition these ciders to make sure we captured as much brett character as possible.
In addition to all of these bottle conditioned ciders, we have filled a handful of casks to naturally carbonate for some of our upcoming events for Virginia Cider Week. There is a Ginger & Honey cask with thai chilis, kaffir lime and lemongrass added, Oak Barrel Reserve with cinnamon and vanilla, a hop cider with Mosaic hops and a couple different casks of Blackberry & Brett cider. Make sure to check our events page or Facebook to see when and where we will be tapping these special creations!