To Add or Not to Add
That is the question! Advances in food science offer winemakers great latitude in wine production. Numerous food companies offer a broad portfolio of additives that can be added to wine to adjust its flavor. These include different tannins, fruit flavors, and aromas. Many wineries that produce inexpensive wines made from low quality grapes utilize these additives to make the wines more palatable.
To achieve agreeable natural flavors in wine requires great skill both in the vineyard and winery. Dedicated management of the vineyard allows the grapes to develop their own interesting complexity in concert with the terroir – geography, soil, and weather. Viticulturists apply proven principles of vineyard management to permit the grapes to reach their maximum quality. These activities include irrigation (where permitted), fertilization, canopy management, and limiting yields.
Winemakers, working with these quality grapes, apply their own skills to coax the best wines from these raw materials. First, winemakers determine the time of harvest by deciding the optimum ripeness of the grape roughly represented by its sugar content (i.e., BRIX level). They then determine the yeasts used during fermentation, the approach to managing the fermentation, and the length of time in complementary oak barrels.
Although some may argue that wine made without flavor additives is still wine that is “manufactured” due to all the manipulation applied in the vineyard and in the winery, I disagree with this view. Use of additives truly makes the wine a beverage no different than flavored juice drinks that taste the same bottle to bottle and year to year. Wine made without these additives tastes different every year, expressing the uniqueness of each vintage.
Each bottle of my wine is a carefully wrapped surprise created by nature that reveals its characteristics only after the cork is pulled. Wine additives destroy this surprise. Therefore, I will never use flavor additives in any of my wines.
Barry P. Chaiken, Proprietor
During fermentation, there are several factors that winemakers take into consideration. The most notable is that of the internal temperature of the must. The biochemical process of fermentation itself creates a lot of residual heat which can take the must out of the ideal temperature range for the wine. Typically, white wine is fermented between 64-68 °F (18-20 °C) though a wine maker
may choose to use a higher temperature to bring out some of the complexity of the wine. Red wine is typically fermented at higher temperatures up to 85 °F (29 °C). Fermentation at higher temperatures may have adverse effect on the wine in stunning the yeast to inactivity and even “boiling off” some of the flavors of the wines. Some winemakers may ferment their red wines at cooler temperatures, more typical of white wines, in order to bring out more fruit flavors.
To control the heat generated during fermentation, the winemaker must choose a suitable vessel size or else use a cooling device. Various kinds of cooling devices are available, ranging from the ancient Bordeaux practice of placing the fermentation vat atop blocks of ice to sophisticated fermentation tanks that have built-in cooling rings.
A risk factor involved with fermentation is the development of chemical residue and spoilage which can be corrected with the addition of sulfur dioxide (SO2), although excess SO2 can lead to a wine fault. A winemaker who wishes to make a wine with high levels of residual sugar (like a dessert wine) may stop fermentation early either by dropping the temperature of the must to stun the yeast or by adding a high level of alcohol (like brandy) to the must to kill off the yeast and create a fortified wine.
Other Types of Fermentation
In winemaking, there are different processes that fall under the title of “Fermentation” but might not follow the same procedure commonly associated with wine fermentation.
Bottle fermentation is a method of sparkling wine production, originating in the Champagne region where after the cuvee has gone through a primary yeast fermentation the wine is then bottled and goes through a secondary fermentation where sugar and additional yeast known as liqueur de tirage is added to the wine. This secondary fermentation is what creates the carbon dioxide bubbles that sparkling wine is known for.
The process of carbonic maceration is also known as whole grape fermentation where instead of yeast being added, the grapes fermentation is encouraged to take place inside the individual grape berries. This method is common in the creation of Beaujolais wine and involves whole clusters of grapes being stored in a closed container with the oxygen in the container being replaced with carbon dioxide. Unlike normal fermentation where yeast converts sugar into alcohol, carbonic maceration works by enzymes within the grape breaking down the cellular matter to form ethanol and other chemical properties. The resulting wines are typically soft and fruity.
Instead of yeast, bacteria play a fundamental role in malolactic fermentation which is essentially the conversion of malic acid into lactic acid. This has the benefit of reducing some of the tartness and making the resulting wine taste softer. Depending on the style of wine that the winemaker is trying to produce, malolactic fermentation may take place at the very same time as the yeast fermentation.