The Winemaker

TIMING THE HARVEST

This is possibly the most important decision the winemaker will face. Picking early will retain acidity, but can produce a green, herbaceous character and hard tannins. Picking later may ensure ripeness but can result in low acidity, higher alcohols and a stewed character. Grapes often ripen very quickly toward the end of the growing season so the window of opportunity is very small, with the consequences of mistakes sometimes quite large. Weather, rot, pests, manpower and even tank space in the winery all have an influence on the eventual decision.

FERMENTATION

During fermentation many decisions are made that will contribute to the ultimate style. Yeast type, fermentation temperature, type of vessel and level of skin contact all play a part, as do additions of sugar and acid, if needed. White juice can be filtered and fermented in stainless steel for clean, fresh flavours or left with some solids and barrel-fermented for complexity. Red wines gain their colour and tannins from the skins, which are regularly submerged. The duration and timing of this will influence the final structure. With timing crucial the wine needs constant monitoring and analysis during this phase.

MATURATION

With fermentation over thoughts turn to the maturation process. Reds and some full-bodied whites will often be stored in oak barrels. The origin of these barrels is crucial, with different species growing in Europe and America, as well as different producers, barrel age, size and even the forests where the oak originated all affecting the flavour profile. Oak ageing also allows some contact with oxygen, softening tannins and stabilising colour in red wines. During this time reds (and a few whites) will also undergo a malolactic fermentation, whereby bacteria transform hard-tasting malic acid to the softer lactic acid.

Wines can also be matured in tank, thereby avoiding any oak and oxygen influence. This is especially important in retaining freshness and varietal character in white wines. Large commercial producers will often imitate oak ageing with the addition of oak chips and small amounts of oxygen.

FINING, FILTRATION AND BOTTLING

Towards the end of the maturation period wines need to be made ready for bottling. Many will be blended to produce a particular style, after which they can be fined and stabilised. This involves adding different compounds and/or proteins which bind to undesirable compounds/proteins in the wine, precipitating them out. This process removes many bitter or astringent flavours and ensures the wine remains bright and clear. Many wines will then undergo filtration to remove any solid particles, with commercial wineries often using special membranes to filter wine to a sterile condition. Some winemakers insist this strips character from the wine and higher quality producers will use very little, if any, fining or filtration. The final step in the chain is bottling which, if done in a clean and professional manner, should have little impact on wine quality, although it is common for wines to suffer ‘bottle shock’ for up to 6 months afterwards.