Wednesday, October 2, 2013

Improving wine balance with varietal blending

Wine blends are constructs of two or more varietals, and/or micro/macro-climates, and or clones, and/or juice types (press or free-run) that are implemented by the winemaker to, among other reasons, overcome wine deficiencies or defects, improve balance, or enhance complexity. I have previously discussed blending and wine complexity and will cover wine balance and blending in this post.

According to Dr. Bruce Zoecklein, Head of the Enology/Wine Chemistry Group at Virginia Tech, wine can be broken down into the three sensory categories indicated in the table below.

                              Wine Sensory Components

Structure                                  Texture                               Flavor
Sweet                                       Light (delicate)                   Nutty
Acid                                         Rich (dense)                       Earthy
Astringency                                                                         Herbal
Bitterness                                                                            Smoky
                                                                                            Tropical Fruit
* Found mainly in white wines
Source: Derived from Figure 1 of Matching Food and Wine.

As regards the structural components, Dr. Zoecklein argues that a balanced relationship must exist between the tastes of sweetness, on the one hand, and acid, astringency and bitterness on the other, in order to yield the perception of a quality wine to the taster.  The preferred relationship is captured in his Palate Balance Equation (Zoecklein: Components of Red Wine Mouthfeel):

           Sweet ⇄ Acid + Phenolics (Astringency and Bitterness),


          Sweet = Carbohydrates + Polysaccharides + Ethanol,
          Acid = Population of organic acids, and
          Phenolics = Skin, seed, and stem phenols + barrel phenols + enological tannins + volatile  phenols.

Based on the foregoing equation, an increase in the sweetness element will lead to a reduction of the taster's perception of acidity and phenolics; and the reverse is also true.  Dr. Zoecklein sees this balance, or harmony, as a key indicator of wine quality and, in that, he is joined by Wines and Vines and Crushpad Blog, among others. According to Chris Stamp, writing in Wines and Vines, "... a balanced wine is a wine in which the various components work together to provide a pleasing taste."  According to Richard Leahy, writing in Crushpad Blog, wines that are in balance tend to stay that way while wines that are out of balance tend to grow moreso over time.

How does balance relate to quality? If, for example, a wine has insufficient sugar in relation to its acids and phenols, it will present as harsh and acidic and will retard the evolution of flavors in the mouth of the taster. A wine with too much sugar, on the other hand, will be flabby and cloying and will not refresh the palate. The sweetness of sugar also balances out the bitterness of phenols. Alcohol adds to the sensation of sweetness in a wine. It also adds a thickness. Too much alcohol and the wine can present as hot, lead to a reduced perception of wine aroma, and can impart a sense of intoxication.  For a winemaker doing business in the US, there is an approximately $.50 difference in the taxes paid per gallon of produced wine if the alcohol level goes beyond 14.001%.

The winemaker needs to know the acid content of the grape and must in order to: decide when to harvest; determine pre-fermentation must treatment; monitor wine stability; and comply with US TTB requirements of 0.5% minimum acid levels. Red table wines generally range between 0.6% and 0.7% TA as levels below 0.4% render the wine susceptible to infection and spoilage. A second method for measuring the acidity of a wine is through observation of its pH (potential of hydrogen) level. The pH level of a wine affects the way it is perceived by the wine drinker as well as its reaction to micro-organisms. Low-pH wines are generally viewed as sour and render tannins more astringent but they also limit micro-organism growth.

Grape tannins provide color, flavor, structure, and texture to the wine and serves a preservative function. Tannin affects wine balance in the following ways:
  • The lower the tannin levels, the greater the amount of acidity the wine can support; conversely, the higher the tannin levels, the lower should be the acidity
    • High-acid, high-tannin wines tend towards astringency
  • Too much tannin results in wines that are heavy on the palate, lacking in finesse, and possessing a rough finish
  • Increasing alcohol content increases the intensity of bitterness and decreases the sensation of astringency
  • Low alcohol levels will result in dominant acidity and astringency and harsh, thin wines
  • Lowering wine pH increases the astringency of the tannins.
To summarize, acid gives wine a tartness and freshness while countering the effect of sweetness and magnifying the astringency of tannins. If a wine has too much acid it will be puckery and sour; too little and it will be flat, flabby, and dull. If a wine has insufficient sugar in relation to its acids and phenols, it will present as harsh and acidic and will retard the evolution of flavors in the mouth. If the wine has too much sugar, it will be flabby and cloying and will not refresh the palate.

Hopefully the normal grape-growing and alcoholic fermentation processes would have produced a balanced wine but if an imbalance were brought about by an insufficiency or excess of any of the elements described above, the winemaker may choose to blend with a varietal that addresses the imbalance. The following are examples of varietals which contribute to balance-enhancement in selected wine blends (Stenwreth MW, Tong 15;;
  • In the Langhe region, Barbera is used to tone down the tannins of the mighty Nebbiolo
  • In California, Petit Sirah is used to add structural backbone to Zinfandel
  • Petit Verdot adds freshness and firmness to blends
  • Malbec, Merlot, and Carmenere soften the tannins of Cabernet Sauvignon in Bordeaux blends
  • Cabernet Franc adds freshness (among other features) in Bordeaux blends
  • Pinot Noir adds body and structure (among other characteristics) to Champagne
  • Chardonnay adds freshness to Champagne
  • Mazuelo adds structure and freshness (among other features) to Rioja wines
  • Graciano adds acidity to Rioja wines
  • Canaiola adds sweetness to Chianti and tempers the harshness of Sangiovese.

©Wine -- Mise en abyme

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