Key Components of Wine
If you plan to produce a high quality wine, first be sure you understand about the main components of the grapes that contribute to a good wine. There are three main elements that are important for making quality wine. Sugar determines the alcoholic content of a final wine and can be used to backsweeten acidic or high alcohol wines. Acidity provides refreshing flavor, balances alcohol and sweetness, and contributes to storage stability. Tannins provide both astringency and bitterness to enhance flavor and mouthfeel while also contributing to storage stability.
Generally 20-26% of the juice (degrees Brix)
Sugar is extremely important for wine production. Sugar is converted into alcohol and carbon dioxide by yeast. The more sugar you start with, the more alcohol you will have in your finished wine. Most wine grape varieties have enough sugar to produce a dry wine of about 11-15% alcohol by volume (ABV). Most wines are traditionally produced solely with the sugars in the grapes themselves, with no additional sugars added. Juice starts out very sweet. But, by the end of fermentation, all the sugar is gone, leaving your wine with just alcohol, acidity and tannins. Some wines are backsweetened by adding a simple syrup or grape concentrate post fermentation to counterbalance alcohol or acidity.
Generally 0.5 - 0.7% of the juice (titratable acidity)
Acidity is a major flavor characteristic of wine. Higher levels of acidity tend to brighten up wines and make them pop. Low acid levels tend to leave wines seeming dull and flabby. The major acid in grapes is tartaric acid, followed by malic acid. Tartaric acid is quite tart and is generally considered desirable in the finished wine. It usually represents about 50-75% of the acid present. Malic acid, on the other hand, is also sharp and tart and usually represents about 25-50% of the acid present. Think of sour, green apples. The acidity can sometimes be high enough to make your lips pucker up. The less desirable malic acid is often converted by the winemaker into softer lactic acid by putting the wine through a malolactic fermentation.
The percent acid (more commonly referred to as TA or titratable acidity) is important to winemakers because it directly affects how you perceive the acidity when you taste the wine. Higher TAs result in more acidic tasting wines. Most wines fall between 0.5 to 0.7% TA, generally on the lower end of the range for reds and the higher end of the range for whites. At The Beverage People we generally recommend a tighter target of 0.55 to 0.65% TA for red wines and 0.6 to 0.7% TA for whites.
Acid adjustments can be done at any time, before or after fermentation. First you must measure the acid level in your must or finished wine. This can be done easily and cheaply at home with a simple Country Wines Acid Test Kit. Once the acid level is known, a target acid level can be determined and the amount of acid needed can be calculated and added.
Generally 0.01-0.15% of the juice (100-1500 ppm, also expressed as 0.1-1.5 grams/liter)
Tannins are complex phenolic compounds that can play a most significant role in wine mouthfeel. Tannins are a source of astringency. Astringency is that drying-out effect that you get on your tongue and in your mouth when you drink dark, black tea. Astringency enhances mouthfeel by making it feel as if the wine has more viscosity, even though it doesn’t. Sometimes high tannin levels can make it seem like there is an extremely fine powder in the wine. Tannins also produce bitterness that gives a wine some of its flavor. This combination of astringency and bitterness combine to give wines their lingering aftertaste, still noticeable after the wine has been swallowed.
Red grapes are usually higher in tannins relative to white grapes, which may have low enough tannin content that it might not even be perceptible. The relatively high tannin content of grapes such as Cabernet Sauvignon and Syrah is what makes them so much better suited to producing more mouth filling and long lived wines. The lower tannin content of most white grapes makes them more refreshing to drink, but also quicker to age and lose their vibrancy.
Adding Tannin to a Low Tannin Wine: If you don’t have access to grape varieties with high tannin levels, you may choose to add tannins to your wine to enhance the flavor and mouthfeel. An easy way to add tannins to wine is with Stellartan G Grape Tannin, a powdered tannin product made from California grapes which will dissolve quickly into wine. This product became a staff favorite at The Beverage People based on group blind tastings. Small additions of Stellartan G to wines can make up for low tannin grapes and improve their age worthiness. Conduct a small scale dosing trial to determine the appropriate level of tannin to add to your beverage. Dosage range typically lies between 0.5-2.5 grams per 5 gallons (25-130 ppm). Keep additions small, generally not in excess of 3 grams per 5 gallons (150 ppm). A 1 gram per 5 gallons (50 ppm) addition is a relatively safe starting point to ensure you don't overdo it.