From Vine to wine
After primary fermentation, the winemaker may decide to allow malolactic fermentation (MLF), in which malic acid is broken down into lactic acid, introducing notes of brioche and butter to the wines.
MLF also generates by-products that modify the organoleptic profile of the wine, mainly by lowering its apparent acidity. Champagne winemakers are generally in favour of MLF, with the exception of a few producers who prefer to avoid it altogether. Most take a pragmatic view, considering it necessary for some wines but not for others.
Where MLF is considered desirable, the cellar temperature is maintained at around 18°C, and the wine tanks are inoculated with selected strains of lyophilized bacteria. The process is complete within 4-6 weeks, checking the rate of progress by monitoring total/titratable acidity, at which point the wines are drawn off and clarified.
Clarification may involve fining, filtering (using kieselguhr earth, membrane/cartridge-type filters or pad filters) cross-flow filtration or centrifuging. The aim is to eliminate the lees and other impurities, producing clear, natural base wines (known locally as ‘vins clairs’) that are ready for blending as a ‘cuvee’ (local term for a blended Champagne). Base wines are classified by varietal, vintage, vineyard (or sometimes the individual vineyard plot) and pressing fraction (whether cuvee or taille).