Technical Wine Terms C to D

  • Can: a familiar sight containing beer, cider and soft drinks. Around 75 percent of drinks cans are aluminum, with the remainder made of tin-plated steel, often with aluminum tops. Aluminum cans are coated internally to protect the metal from oxidation. Even so, trace elements can degrade into the liquid. Partly due to improved linings and manufacture, in recent years canned wines have become more common. Consequently, the quality levels of the liquids in them have risen (for example canned Napa Valley Cabernet Sauvignon is now relatively easy to find).

    The containers are promoted for having a lower carbon footprint and being easier to recycle than glass bottles. Wines can also be chilled more quickly, which along with portability and ease of opening makes them ideal for outdoor events. Most producers concede that the cans are not meant for long-term aging, and (like many brewers) recommend pouring the liquid into a glass.

  • Carbonic maceration: a winemaking technique most commonly associated with the Beaujolais region of France. Grapes are whole-bunch fermented in a sealed container which has been flushed with carbon dioxide, creating an anaerobic (oxygen-free) environment. Fermentation begins inside the still-whole berries, creating aromatic flavor compounds (phenols) not found in conventional fermentations. These compounds are responsible for the 'banana' and 'bubblegum' aromas associated with carbonically macerated wines. The technique produces wines which are fruitier and less tannic than those made from crushed grapes. Genuine, pure carbonic maceration is very hard to achieve, because the grapes at the bottom of the container typically split under the weight of the fruit above.

  • Chaptalization: a winemaking process where sugar or concentrated grape juice is added to grape must prior to fermentation, in order to increase its potential alcohol. This form of 'must enrichment' (see also cryoextraction) is most often practiced in wine regions whose cool climate makes it difficult for grapes to reach optimum ripeness. Chaptalization is not a well-regarded practice, and is illegal in some countries (most obviously Italy).

  • Charmat: a sparkling wine production process involving a secondary fermentation in pressurized stainless steel tanks. Once this second fermentation is complete, the wine is filtered and bottled under pressure. This is distinct from the Methode Champenoise, in which secondary fermentation takes place inside the bottle. The Charmat method is known by various other names, including 'Methode Cuve Close', 'Metodo Charmat-Martinotti', 'Metodo Italiano', and 'Tank Method'.

  • Climat: a Burgundy-specific term for 'vineyard site', effectively synonymous with 'cru'. The word encapsulates both a vineyard site's location and its terroir.

  • Continental climate: a climate characterized by strong temperature variations from day to night and between the seasons. Continental climates tend to be found in the interior regions of large landmasses (whence 'continental').

  • Cool-climate viticulture: denotes the particular viticultural techniques used in cool-climate wine regions. This may be something as straightforward as selecting cold-hardy or early-ripening grape varieties (e.g. Chardonnay or Vidal), or as complex as rolling out comprehensive frost-protection systems across entire vineyard areas. Cool-climate growing conditions are typically found at high latitudes and high altitudes. Almost all regions of Germany, Switzerland and Austria are considered to be 'cool-climate' wine regions. Other examples include the Loire Valley and Champagne in France, California's Anderson Valley, the Columbia Valley in Washington State, and the Australian island of Tasmania.

  • Cork: the most widely used closure for wine, employed by ancient Greeks and Romans. Its current form dates back to the 18th Century, when it was developed alongside the corkscrew. Cork is a renewable resource harvested from Quercus suber, the cork oak, which mainly grows in strictly protected forests in Portugal and Spain. The trees regenerate their outer layer, allowing a harvest about once per decade. Cork has natural elasticity and expands within the bottle neck to keep liquid in and excess air out. The pores in the cork do allow enough oxygen in to interact with the wine sufficiently to alter aroma and taste over time.

    Cork is susceptible to TCA – past studies have suggested as many as 10 percent of bottles were affected by cork taint. However, in the past 10-15 years the main cork producers have introduced various hygiene and monitoring innovations, and some more recent studies have put the figure at around 1 percent – around the same rate of bottles that suffer from air ingress due to damaged screwcaps. Natural cork stoppers are inherently more variable in terms of porousness compared to agglomerated corks and other homogenized manufactured closings. They are also fragile, and bottles must be kept on their sides to avoid drying out the cork, causing it to crumble. Cost is also a factor; this can vary widely according to quality, but the best natural corks are the most expensive of all options for commercial bottling.

  • Cork twin top: an agglomerated cork with a disk of natural cork on each end. Generally recommended for wines for early drinking.

  • Crown cap: a closure most readily associated with beer, and often called a beer cap. It takes its name from its appearance when lying with its inner surface on view. It is sometimes used some categories of sparkling and semi-sparkling wine, including pétillant-naturel wine, which is not disgorged. Some natural wine producers also place still wines under crown cap. Most Champagne undergoes its second fermentation in the bottle under a crown cap.

  • Cryoextraction: a sweet-wine production process developed in the 1980s, which artificially replicates the early stages of natural icewine production. Grapes are frozen before they are pressed, separating water out from the sugar-rich juices and creating a richer, sweeter must. The technique is most useful in cooler vintages, when sugar levels are insufficient to produce quality sweet wines. See also chaptalization.

  • Deacidification: the process of reducing acidity levels in grape must, most common in cooler climates where grapes struggle to ripen (leaving them with too much acid and too little sugar). Dilution (with water) followed by enrichment (with sugar) is the most widely used technique, but the addition of calcium carbonate (which precipitates out excess acid) is also a recognized method. Malolactic fermentation can also help to reduce excessive acidity.

  • DIAM: a producer of manufactured cork enclosures. The cork is boiled and ground before supercritical (state midway between gas and liquid) CO2 is applied to remove flavor modifiers such as TCA. Particles are sorted, cleaned and bound with food-quality binders and microspheres. Each cork is then molded, baked, machined, branded and dated. Wine producers can choose from various levels of permeability. Versions for sparkling wine and T-corks for spirits are branded as Mytil and Altop, respectively.

  • Disgorgement: a stage in sparkling wine production, whereby the lees on which the wine has been aged are removed from the bottle necks (it applies only to the methode traditionelle). By immersing the inverted bottles into a freezing solution, the lees solidify into a single frozen pellet. When the seal is removed from the bottle, this pellet is ejected, propelled by the pressurized carbon dioxide created by the primary fermentation. The space created in the bottle by the ejected lees is then filled with a mixture of wine and sugars (see dosage).

  • Diurnal temperature variation: the difference between the highest temperature of the day and the lowest temperature of the night. This variation in temperatures has a significant impact on a grape's ripening pattern; the heat of the day promotes sugar accumulation, while the cooler night-time temperatures preserves acidity levels.

  • Dosage: a term mostly used in the production of sparkling wines, referring to the process of topping up a bottle to adjust the sweetness level as well as the volume. This mixture usually consists of wine and sugar, but on rare occasions it can also include alcohol to 'lift' the alcoholic strength of the final product.