Wine Components

There are many factors affecting the wine, not only the grape variety. These factors include country and region of origin, climate, temperature, rain amount and soil conditions, the so called terroir, and of course the individual wine maker.

In other words it is not just the flavour you have to pay attention to but also the structure of the wine. Knowing the components of wine will help you understand and enjoy wine better.

The balance of tannins, body, acidity, alcohol and other components like sugar and oak of a wine is important to know.

Fullness or Body

Fullness or body is a texture or mouth feel that you are experiencing with the sense of touch. The terms used to describe the general weight (body) of a wine are light, medium-bodied and full-bodied. A full-bodied wine is comparable with cream or concentrated juice while a light may be compared with low-fat milk or diluted juice.

The body and the tannins (astringency) of a wine are balanced which means that a full-bodied wine is rich in tannins. Full-bodied wines are big and powerful and light-bodied wines are more delicate and lean. The majority of wines fall into the group of medium-bodied wines.

Tannins or Astringency

The tannins in a wine are derived from the pips, skins and stalks.

The tannins give structure and backbone to the wine. Red wine contains more tannins than white. Tannins have a drying out effect – you may get a feeling that the upper lip sticks to the teeth, a sensation very similar to what happens on drinking stewed tea.

Tannins are of more importance in the aging of red wines rather than white. The tannins act as a preservative, and as they fade over many years, the simple, primary fruit flavours have time to develop into the more complex flavours that are found in fine, aged wines.

Tannins may also have different qualities, light-bodied wines have soft tannins and full-bodied more stringent tannins.


Fruit Acid is the backbone in a wine. Acidity can be detected by the sharpness of the wine in the mouth, particularly around the edges of the tongue near the front. Higher acidity denotes a wine from a cooler region, such as Northern France, England or New Zealand. Low acid wines come from countries with warmer weather, such as Australia where acidity in the harvested grapes is often low enough to warrant chemical acidification.


The use of oak plays a significant role in winemaking and can have a profound effect on the resulting wine, affecting the colour, flavour, tannin profile and texture of the wine. Many wines are matured in oak barrels, and some are even fermented in oak.

Oak is porous and allows small amounts of oxygen to pass into the wine, a process called microoxidation. It is this process that is the secret behind the oak influence on the wine. The oxygen is namely catalyst for a variety of chemical processes.

One effect is that he colour of the wine is intensified by the oak tannins.

Another important effect is that of the natural tannins become softer. This is done through a so-called polymerization, a chemical reaction in which small molecules clump together and form a chain. The chain eventually becomes so large and heavy that it falls to the bottom of the barrel. The result is a less harsh wine.

Oak can come into contact with wine in the form of a barrel during the fermentation or aging periods. It can also be introduced to the wine in the form of free-floating oak chips or as wood staves (or sticks) added to wine in a fermentation vessel like stainless steel.

Oak from different sources will impart different characteristics on the wine, but in general oak maturation gives aromas of butter, toffee, caramel, vanilla, spice and butterscotch.

French oak may give more buttery aromas, whereas American oak gives stronger vanilla and spice aromas, but there are many more variables in the equation than this simple statement suggests.

It all depends on how much oak is used, how much of it is new as opposed to re-used, how long the wine stays in contact with the wood, whether the wine is merely aged in oak or whether the fermentation takes place in it, how the oak has been treated, and so on. For instance, barrels that have been “toasted”, which means the cooper has formed them around a small fire, often burning the oak shavings he has produced in the manufacturing process, will have aromas of smoke and toast. Barrels that have been steamed during manufacture, however, may give more oatmeal aromas.


Alcohol is the product of fermentation of the natural grape sugars by yeasts, and without it wine simply doesn't exist. The amount of sugar in the grapes determines what the final alcohol level will be. In cool climates, such as Germany, where the vines struggle to ripen their grapes, sugar levels will be minimal, and consequently such wines often only reach 7 or 8% strength. In very warm climates, however, the final alcohol level will be determined not so much by the amount of sugar but rather by the yeasts themselves. Once the alcohol level reaches about 14% the yeasts can no longer function and rapidly die off. For this reason, wines with a strength of more than 15% are almost certainly fortified.

The conversion of sugar to alcohol is such a vital step in the process of making wine, that the control of fermentation is the focus of much of the attention of the modern winemaker. Fermentation generates heat, and a cool, controlled fermentation will result in very different flavours in the wine (in particular, it protects fresh, delicate fruit flavours) when compared with wines where fermentation is allowed to run riot. Although fermentation will start naturally, thanks to yeasts naturally present on the grapes in the vineyard, some winemakers prefer to remove the element of chance this involves by kick-starting fermentation using cultured strains of yeast.


If fermentation is arrested, either as a result of the yeasts not being able to convert any more sugar due to gradually increasing alcohol level in the ferment, or as a result of intervention by wine maker, there will as a consequence be some remaining sugar in the wine. Even when the yeasts work is unhindered, most wines still have at least 1g/l of residual sugar as some sugar compounds are resistant to the action of the yeasts. Clearly, the level of sugar in the wine determines how sweet it tastes. This is quite subjective, however, and even wines that taste very dry have some degree of residual sugar. Most dry wines have less than 2g/l of sugar, although levels of up to 25g/l may be present in wines which still taste dry due to the presence of acidity and tannin alongside the sugar.

All materials on this site are protected by international copyright