The past few posts have covered individual elements that you taste in a wine: acidity, tannins, sweetness, alcohol, and body. If you remember, tannin isn't really sensed by taste, but actually by touch. This post will get a little nerdy with a bit of science (sorry).
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| Wine has a pH of 3-4 image from theelectricbrewery.com |
Acidity
High acidity is sensed as sourness. Interestingly, everybody's point of sensing sour is different. I have witnessed different people tasting the same Sauvignon Blanc (a high acid wine) served at the same time and temperature, with different reactions. Most called it something like brisk and refreshing. Occasionally someone said, ohh, that's sour. Some people are in between and describe it as sharp.
The main acids found in grapes are tartaric, malic, and citric. Malic and citric are widely found in other foods. Tartaric, the main acid found in grapes, is otherwise rare. Other acids are produced during fermentation. Ascorbic acid can be added as an antioxidant during wine making. Antioxidants inhibit oxidation (spoilage) and are used in other food products.
Often the malic acid (think of biting into an under ripe apple) is converted to lactic acid (milk acid) during wine making to soften the effects of the acids.
Sometimes total or titratable acidity (TA) is listed on a wine label or the wine's tech sheet at the winery's website. It's shown as grams per liter or a percentage, so a higher number means more.
Volatile acidity (VA) is mostly acetic acid (vinegar), created during fermentation.
You've maybe seen acids shown as a pH value. This is a scale of zero to 14 with seven being neutral, or the same as water. A lower number means higher acidity. To add to the confusion, the scale is logarithmic so a pH of four is ten times more acidic than a pH of five. The juice of a lemon is between two and three. Wine is between three and four.
Tannins
Tannins are a bit different from other components of wine that you sense by smell and taste. Tannins you feel, often by a mouth-drying sensation. But you can also get bitterness (taste) and astringency (mouthfeel). A little bit of bitter or astringent can be good, but if it's overwhelming, it's bad. Tannins are "sticky" so they stick to the inside of your mouth. The best tannin eraser is something fatty like cheese or salami.
Tannins and acids can counter sweetness; likewise, sweetness can hide high tannins. Cranberry juice is either going to have a lot of sugar or artificial sweeteners because it's high in tannins. There's actually some research showing that a particular tannin in cranberry juice might help fight certain E. coli bacteria.
The temperature of the drink, whether wine, coffee, tea, cranberry juice, is important as the perception of bitterness, astringency, and sourness from tannins and acids change. White wines tend to have higher acid than reds, but much less tannin.
Sweetness
Sweetness comes from three places.
- One is actual residual sugar (RS) left in the wine. There is a tiny bit left in any fermented wine, but there's a threshold where you actually can taste it, usually considered to be 0.5% RS.
- Another source is from the alcohol, as it will taste sweet if there's a lot of it left in the wine.
- The third source is interesting, as it's the brain's interpretation of the fruity smells and flavors of a wine. Many California wines have ripe fruit flavors. Even though the wine may have no residual sugar or lower alcohol you still think you taste sweet because you know ripe fruit is sweet, so you associate the smell and taste with sugar.
Sugar / Acid Balance
Sweetness and acidity require balance. Granny Smith apples are on the acidic side and taste tart. Gala are low acid/high sweetness and you might call them soft and mellow tasting.
Champagnes and other sparkling wines are made from grapes picked earlier than other table wines. This means the grapes have lots of acids and not as much sugar yet. These wines are first fermented into a very tart still wine, then sugar is added with more yeast to create the bubbles and to balance out the wine's acidity with whatever level of sweetness the winemaker is going for. A very low dosage (doe-sahj) with make a tart wine, a very high one will give you a sweet sparkling wine.
Riesling and Muscato are popular sweet wines. Riesling is quite acidic, so a very dry one would not be that pleasant, but they are made with different levels of sweetness from residual sugar to make anything from a dinner wine to a dessert wine. The more sugar left unfermented, the lower the alcohol level.
Most table wines have traditionally been fermented dry, with no discernible sweetness from residual sugar. However, California and other New World producers have learned many consumers want a slightly sweet wine, yes even a Napa Cabernet! There are numerous premium wines with RS, but you'll likely never get the winery to admit to it. Is this somehow bad? Not necessarily, it's just non-traditional meaning that's not the Old World way of making wine.
The Interaction of acid, tannin, and sweetness
As you can see, even based on this simple overview, the interaction of the basic elements in wine is complex. None of us normal folk will ever fully understand it, just know that it exists.
Some of the info is from:
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