VINIFICATION: Is it Wine Yet?

Bulgarian Grape Harvest

Sun, soil and water combine to nurture the physical and physiological ripeness(ripe tannins) of a vineyards wine grapes where sugars and acids are in balance for the winemaker. Once extracted it is just fruit juice, but, it becomes wine as our harvest season begins anew when the inevitable variables of nature are controlled in the cellar. Truth is, great wine comes from preserving the integrity of great fruit from well managed, sun-drenched vineyards. Vinification needs great viticulture. It is the wine-grapes 6-carbon ferment-able sugars, glucose and fructose, that get converted into carbon dioxide and ethyl-alcohol by hungry little enzymes of yeast, either native or cultured. Five(5) carbon sugars remain un-fermented in solution, but are generally unrecognizable in wine. A volatile, heat-generating process, a controlled alcoholic fermentation produces additional compounds that reside in the finished wine, such as acetaldehydes, phenolics(anthocynins), and even a little byproduct of sulfur dioxide. But, I'm getting ahead of myself.  The winemaker's choices of controlling many winegrape variables start early in the process.

In the cellar, it quickly becomes about the choices made by the modern winemaker; about their ability to control what nature provides. Do they de-stem the berries or ferment the whole clusters of fruit increasing the measure of air circulation and bitter tannins?  Will there be a pre-fermentation 'cold-soak' or cold maceration to soften seed tannins, enhance extraction, color, and aromas?. If so, for how long? Employed mostly on Burgundian varietals, this procedure still has its critics that discount its winemaking virtues. One thing is for certain though, a controlled cold maceration slows down the cellar process, extracts water-soluble pigments, and gives the wine maker more time to control a few variables. Extracting as much flavor or character is paramount, as well as preserving the color and the right balanced levels of the many acids in the young wine. Prior to fermentation, acid and sugars are measured to calculate the character of the finished wine.  Fragile white wines ferment just the juice of the berries in cooled temperatures and with very calculated, limited exposure to oxygen to preserve aromatics and freshness. Red wines by comparison are fermented on their skins to extract the character of color and structure, and benefit from oxygen exposure.

Chardonnay ready to Press

Yeasts are the catalysts of alcoholic fermentation in the cellar, so a yeast selection that produces greater control of the outcome(cultured) may be beneficial over native(wild) yeasts that live on grape skins, which can produce higher levels of alcohols and acetaldehydes. A cooler fermentation for white wines would follow a press, a juice settling(de'bourbage) and adjustments to acid or sugar(chaptalization) levels. A secondary fermentation may be introduced following primary fermentation here, changing the tart malic acids for the softer lactic acids(malolactic). And then in a series of steps intended to develop complexities and clean-up the new wine, it is racked to remove the dead cells(lees), adjusted, clarified and stabilized prior to its blending and bottling. Some white wines, notably Chardonnay, become rounder, more complex from being fermented in oak barrels rather than the more common stainless steel tank.

A warmer red wine fermentation is engaged prior to pressing the solids, where the hotter temperatures aid extraction of critical wine elements like color and flavor components from the pulp and grape skins. A malolactic or secondary fermentation is introduced to most red wines here to soften its coarse and aggressively tannic nature prior to an extended maceration which can include aerating the wine, and pressing off the juice. A calculated aging schedule in barrels allows for evaporation(concentration) and oxidation of the new red wine, as well as the softening of its course tannins, which pulls suspended particles out of solution and adds the dimension of oak flavors.  As with white wines, red wine clarification and stabilization is needed, and can happen before, during or after the aging process. Alternative whole-berry fermentation or Carbonic Maceration is practiced in oxygen-free environments where the freshness of red fruit is to be preserved. Typically lower in alcohol, tannin and pigments, the natural sugars in these grapes are broken down without the intervention of yeasts, resulting in fruitier wines like Beaujolais Nouveau.

Carbonic Maceration Tanks

Along the way, the winemaker uses a number of steps to control variables, such as sulfur adjustments to control yeast action, eliminate spoilage or browning. The new wine can be further processed by using techniques like heat or cold stabilization to remove unwanted proteins or to remove tartaric acid crystals respectively. Fining agents which bond to suspended particles, and micro-filtering give winemakers yet another way to clean-up and control the many variables in the winemaking process.  It is all about timing and calculated choices in a series of  time-tested steps that preserve the integrity of the vineyard fruit prior to bottling for every winemaker.

Aeration of the wine 'cap'

As you expect, many variations exist within the process.  Arresting the fermentation prior to all the sugars fermenting will create a sweet wine.  If achieved by the addition of alcohol, you have a fortified wine(VDN). Should the winemaker capture the escaping gas(CO2), either in the bottle or a tank, a sparkling wine is the result. Exposing an aging wine to air can create a slowly oxidized wine(Sherry), or heating the finished, fortified wine to create something unique, like a Madeira.  Making fine wine is not really a simple process.  It is the wonderful marriage of science and art, that advanced dramatically thru the development of the agricultural  sciences in the last half of the 19th century. Controlling what nature provides allows the modern winemaker to determine when the best grapes of each harvest become the best wine he can create.

Unclassified Pomerol Cru Merlot

Only then is it wine!

Cheers!