The chilling story of how we make wine
We love heat in the vineyard. But in the winery… not so much.
Cool temperatures are great to develop fruity flavours when you ferment a wine such as Sauvignon Blanc. That is why you’d often see on a tasting note that the wine was “cool fermented”. By keeping the ferment cool, we can control the metabolic rate of the yeast, thereby influencing how it converts sugar into alcohol and also what flavours are enhanced in the process.
Of course, keeping the wine cool after fermentation helps to lock in the flavours.
Because cooling is so important in winemaking, our Marlborough winery was especially designed with this in mind. Louvres open at night to allow cool air in, and are closed when day temperatures rise to keep the cool air inside. Having a smaller differential between the ambient temperature and the desired temperature of the wine means we need to use less energy.
There is one exception to this chilled-out approach: To start fermentation, we often need to warm up the juice a bit, so the yeast can get going.
Rather than spend a lot of energy to generate heat, we use technology to recover the latent heat released by our usual refrigeration processes, and use that for heating. In effect, the same energy that is already used for cooling some tanks is used to heat others! Pretty neat.