Why does my Wine smell bad?

You open your bottle of wine expecting to find the smell of black cherries and black berries, but instead you find the most undesirable smell. You think, “What’s that stink? What’s wrong with my wine?” Your wine is affected by a wine fault. Wine faults are reactions in your wine by either compounds, microbes, and problems in the winemaking process. 

One common fault is called cork taint or corked. If the wine gets into contact with a mold that grows in the cork the wine can become infected with 2,4,6 - Trichloroanisole (TCA). Cork taint can also come from infected barrels and cardboard. This fault gives the wine aromas of musty damp basement and wet cardboard. Luckily, cork producers have worked hard to try to eliminate the possibility of tainted cork from entering the wine industry. 

Another common fault results from sulfur compounds. Sulfur dioxide (SO2) is commonly used in the process of winemaking to preserve the wine. In larger quantities, it will give the wine a burnt match smell that can burn your nose and throat. Additionally, when excess Sulfur is void of oxygen, the wine will become reductive and be affected by Hydrogen Sulfide (H2S). These reductive aromas smell like rotten eggs, garlic, struck matches, and burnt rubber. Winemakers can work to eliminate these reductive aromas by splashing the wine to introduce oxygen.

So what do you do if you open a bottle and it has reductive aromas? You can remove some or all of the undesirable smells by leaving your wine bottle open for a bit or swirl it around in the glass to introduce some oxygen into your wine. The more desirable aromas should become more apparent with the addition of oxygen. 

However, too much oxygen is not a good thing. A wine can become oxidized or maderized if it comes into contact with oxygen for an extended period of time. The dissolved oxygen forms a chemical reaction to create acetaldehyde. The aromas of oxidation are nutty, caramelized, cooked apples, and sherry. Additionally, the hue of an oxidized wine will become more brown in color. This reaction can not be reversed in the winemaking process. Sherry wines are purposefully oxidized during their winemaking. However, if you open a bottle that is not Sherry with Sherry characteristics; it is definitely oxidized, and it is a fault. 

Other faults can be caused by bacteria. Lactic Bacteria and Acetobacter can cause reactions in wine that result in unwanted aromas. Volatile acidity is one fault caused by bacteria that forms acetic acid resulting in a vinegar aroma. Ethyl Acetate is another aroma with a very discernible scent of nail polish remover. 

So if you open a slightly reductive bottle, you are in luck. With a bit of oxygen, you can still enjoy your wine. Other faults will deem your bottle undrinkable, and it is best to open another to savor. 

Cheers!