How is white wine made?
White wine making is quite a simple in concept. So how is white wine made? A winemaker receives the freshly harvested grapes, presses the juice, ferments it using yeasts, lets it mature and then bottles the wine. What do we expect or look for in the grape before harvesting? Freshness and acidity! The opposite of what we will look for when making red wine, where we will look for a riper grape, that will have more sugar.
Some other key factors to consider.
1) The time of harvest: Maturity is an important factor that affects the taste of the wine, so it is important to harvest at the exact moment of the maturity.
2) Picking the grapes at cool temperatures: Picking in the morning or at night ensures that the grapes produce white wines with a fresher flavour and, of course, when taking them to the winery, we don’t want to have high temperatures. Lower temperatures will insure that oxidation and fermentation don’t start during transportation.
Once we have collected the grapes, we select them, destem and crush them. The next step is pressing. The press squeezes the juice from the grapes that is collected in a tank. During this step, sulfur dioxide is added to stop bacterial spoilage before fermentation begins. Then we let the juice settle. We call this the sedimentation process, which helps remove solids in wine that tend to give off-flavours such as bitterness.
From there we add yeasts to start the fermentation. Industrial yeasts allow winemakers to produce very consistent wines year after year. Indigenous yeasts are more difficult to control, but they often result in really interesting and unique tasting wines.
Alcoholic fermentation takes about 14 days for white wines. To preserve the delicate floral aromas, white wines ferment at colder temperatures than red wines. White wine is rarely placed in an open fermentation tank, because it is very important to avoid any oxidation during this phase.
One interesting thing to note about winemaking in general is that the winemaker controls the level of sweetness. If a winemaker wants a slightly sweet or “slightly dry” wine, he can simply prevent the yeast from eating the sugars (usually by chilling it). We call the remaining sugar “residual sugar.”
Are you not a white wine drinker? Do you prefer red?
Well, here we can add one more step to achieve a much more complex white wine, more full-flavoured and buttery.
But … how do we do it? Malolactic fermentation is the answer, after the alcoholic fermentation we can do the malolactic which basically is to convert the malic acid into lactic acid. This will help us achieve a really creamy, smooth wine with a buttery flavour. If this makes you think of Chardonnay, you are absolutely right! That creaminess that you get from most Chardonnay is not so much a characteristic of the grape, but of this particular winemaking process.
What about ageing?
During the ageing, the winemaker may use a number of techniques that will add complexity to the finished wine. The most common for white wines is battonage. This is the mixture of decomposed yeast cells known as lees in wine. Usually they will be filtered out, but when making more complex whites, the lees can stay in contact with the wine for a certain period of time to add extra flavour and body.
After the aging process is complete, white wines often go through the cold stabilisation process, in which tartaric acid is removed from the wine by keeping the temperature constantly low for several days. The tartaric acid may form small crystals in the wine with time. Even though they don’t affect taste, the wine will be clearer and won’t have any solids floating around that may scare a less experienced wine drinker.
The winemaker may also choose to refine or filter the wine before to bottling, as well as add additional sulfur to the wine to ensure a healthy product once the wine has been bottled.
Beyond all the varieties that exist in the world and the different microclimates, each producer has their own way of making wine, so each wine is different.
Even though these are some basic notions of how white wine is made, each one will be different, as each wine maker will have their own way of working, so before you judge any wine at all based on some previous information about the production, it is always best to try with an open mind and discover new flavours!