what are wine faults?

What is the point of tasting a freshly opened bottle of wine before it’s poured? What are you looking for? How many bottles of wine that you open at home are defective?

The best-known flaw is ‘corkiness,’ and this is the only absolute flaw; if a wine shows any amount of this, it is defective. The other flaws are matters of degree, which is to say they only become a problem when they become very noticeable. This is a matter of taste, but an important aspect of all of these characteristics is that they interfere with the flavor of the wine, thereby making the wine less distinctive. Wines that show noticeable Brettanomyces, for example, tend to taste similar, whether they come from Dry Creek or the Douro. I like wines that are distinctive and different, and for that reason, I prefer wines that show little or none of these characteristics. Once you can recognize these flavors for what they are, you can decide for yourself what style appeals to you the most. (I have included several attributes that are often thought to be faults, but usually aren’t, for reference.)

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visible faults

sediment

Sediment may be a flaw if unusually heavy, or if the wine is being poured by the glass (more of a service flaw than a wine flaw, really), but wines that are not overly processed (both red and white) will sometimes throw sediment. This sediment is composed mostly of tartaric acid and is harmless. It is a sign that the wine has not been heavily processed in the winery. Let the wine settle and decant, or just pour carefully.

cloudiness

In classic winemaking, haze would be a defect, but ‘natural’ wines are often not fined or filtered, and will sometimes have a visible haze. White wines made with skin contact will often be hazy on purpose. Prosecco bottled ‘Col Fondo’ (‘with sediment’) is deliberately hazy.

bubbles in still wine

Occasionally bubbles signify a wine that is re-fermenting in the bottle, but it is far more likely that the wine simply still contains some dissolved CO2 from primary fermentation, which will dissipate as the wine sits in the glass. (Splashing the wine into a jug will speed up this process.) Some Pinot Noirs are this way, and many white wines fermented in stainless steel (most of the Italian white wines we import have a little residual CO2, particularly early in the vintage). Unless the wine is re-fermenting, this is not a fault, but individual thresholds vary; to my taste a hint of CO2 adds freshness to both white and red wines made in a forward, commercial style.

lack of bubbles in sparkling wines

A flaw, unless you’ve been aging a fine Champagne for decades.

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tasteable faults

cork taint

TCA smells like a moldy basement or damp newspaper and is perceptible at extremely low concentrations (as low as 2 parts per trillion, amazingly). This is the only absolute fault, which is to say cork taint is always a defect, at any concentration. (All other faults are only faults when they reach unacceptable levels.) Cork taint is caused primarily by a chemical called 2,4,6-Trichloroanisole, TCA for short, which is introduced into the cork by the interaction of micro-organisms and chlorine compounds, and then leaches into the wine from the cork.

It affects at least 2% of the wine bottled under cork, at every level of quality, and is the most common wine fault we come across. Once you identify the smell you will start to notice it in other settings, such as when buying produce (potatoes, bananas and apples are often affected). At lower concentrations corkiness ‘scalps’ (reduces the intensity of) the flavor and aroma of wine; sometimes low levels of TCA will become apparent after the wine has been poured for a few minutes. Although TCA is very rarely a contaminant in wineries, affecting whole bottlings or indeed whole vintages, the great majority of TCA is introduced into wine by bark corks. This is the only defect that is properly referred to as ‘corked,’ although the word is often misused. The increasing use of screwcaps is a reaction to this problem.

Returns: if you smell even a hint of cork taint you are always entitled to return or reject the wine. Cork taint is almost always an individual bottle fault, not a batch fault. Cork taint smells and tastes horrible but is not toxic at the levels found in wine. (If you get in the habit of sniffing the cork right after you open the wine you will often catch TCA immediately, I always do this.)

Brettanomyces

Brettanomyces bruxellensis, or Brett, is a wild yeast that is common in red wine. At low levels, it is said to be attractive, spicy, or smoky, but at higher levels, it produces unpleasant aromas and flavors of Band-aid, barnyard, burnt wood, ‘mousiness’ and ‘horsiness,’ as well as a distinct bitter finish. (This bitter finishing twinge is a good way of identifying Brett.) The increasing popularity of ‘natural’ winemaking has led to an increased incidence of Brett due to the tendency of natural winemakers to use minimal levels of SO2 to protect their wines.

In my opinion, obviously, Brett interferes with the character of interesting wines and makes them less distinctive. Brettanomyces is a batch fault. Sidenote: Brettanomyces is used as a primary fermentation yeast by Belgian brewers (the full name of the microbe is Brettanomyces Bruxellensis, after the city of Brussels), and the distinctive aroma it imparts is attractive in these beers.

Returns: if Brett is an obvious aroma and flavor in a wine, most places will take it back, unless it was sold as ‘natural,’ in which case it may be an intentional character.

oxidation

White wines that are oxidized due to cork failure or for other reasons will tend to be golden in color, and will smell like windfall apples, apple cider, or nuts. Oxidized red wines will be more orange or even brownish in color than usual, and will smell somewhat like flat Coke or caramel. (This fault is sometimes called maderisation.) In classic winemaking this is always a fault, but in recent years some ‘natural’ winemakers have allowed a certain amount of oxidation by not using sulfur dioxide as a preservative. In this case, all bottles will be consistently oxidized.

A partial failure of the cork in a particular bottle can cause ‘random oxidation,’ where that bottle is noticeably different in color and more ‘tired’ than other bottles of the same wine. I think that more cork-finished wines are affected by this random kind of oxidation than are affected by corkiness. Note that some classic wine types are oxidized on purpose, for example so called Orange wines, Amontillado Sherry, Vin Santo or Tawny Port. Oxidation can be either an individual bottle fault or a batch fault as discussed above.

Returns: if you are sure that the wine is oxidized (if a new bottle is clearly different) then you should always be able to return it.

volatile acidity or va

VA is caused by the action of vinegar bacteria (Acetobacter) in wine, and the resulting creation of acetic acid, which is volatile at room temperature. What we actually end up perceiving is a chemical called ethyl acetate, which smells like nail-polish remover or airplane glue (acetone). At low concentrations, this can ‘lift’ the aroma of the wine, and it is often present in small amounts in certain traditionally made wines, such as Barolo, Sauternes, old-vine Zinfandel or Amarone, but at higher concentrations, it is obtrusive and interferes with the character of the wine.

Returns: if you can clearly smell something like nail-polish remover or model-airplane glue, return the wine. Volatile acidity is mostly a batch fault.

reductiveness

Sometimes wines will be said to be ‘reduced,’ an often confusing chemical term that can either mean the wine is ‘closed,’ sometimes smelling like wet wool or wet dog, or mean that the wine suffers from a range of unpleasant off-aromas that are produced under reductive conditions (without the presence of oxygen). ‘Closed’ wines are not defective, and will usually improve with air within a few minutes, or they can be decanted.

To better understand the complicated topic of the volatile sulphur compounds responsible for ‘reductive’ aromas in wine, read Jamie Goode’s article called ‘Mercaptans and other volatile sulphur compounds in wine’, http://www.wineanorak.com/mercaptansinwine.htm. Reduction is a batch fault.

Returns: reduced wines will often improve dramatically with a few minutes in the glass, and wines that do improve are not defective. If wines show persistent rubbery or cabbagey notes, they should be returned.

excessive use of so2

Very occasionally you will find wines that show excess SO2, often wines that have been very recently bottled. This shows as an acrid sulfurous matchstick note that is very obvious and will blow off with air. If this happens to you at home, put the cork back in the bottle and give it a good shake. Excess SO2 is a batch fault, but easy to treat by aeration; I would not return wines for this reason. I have noticed this most often with high-quality German wines intended for aging in the bottle. 

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wine styles and wine faults

If we divide wine into three stylistic camps along a continuum, ‘international,’ ‘terroir,’ and ‘natural,’ then the incidence of faults could be described as very low or nil at the international end, nil to moderate in the middle, and from nil to occasionally very high at the natural end. It is much harder to make wines that avoid the classic faults when practicing ‘natural’ winemaking, particularly because the main way wineries prevent oxidation and Brett is by the use of SO2, and ‘natural’ winemakers tend to use low levels of this preservative, or in some cases none at all.

What is SO2? Sulfur dioxide is a preservative that most winemakers believe is crucial to the production of good wine, and that is added in very small amounts to most wine. (The ‘contains sulfites’ statement on all wine labels usually refers to this addition.) It protects the wine from oxidation, and it inhibits the growth of micro-organisms like Brett, which is to say it prevents both of the most common wine faults very effectively. Competent winemakers use as little of it as possible, just enough to protect the wine, and work to ensure that the amount added remains effective. In my opinion, judicious use of SO2 is a good thing. If you are diagnosed as sulfite-sensitive you should of course be aware of this, but the amount used in most well-made wines these days is far less than the permitted maximum. (NOTE: if you think you might be sulfite-sensitive, ask your doctor. Wine-related headaches are often caused by other factors; see the Wikipedia article on Red Wine Headache for more information.) 

Closures

Two of the leading bottle-by-bottle wine flaws, corkiness and random oxidation, are by-products of the use of bark corks. The increasing use of screwcaps is an attempt to deal with these problems, and with the bottle variation that is inherent in the use of bark corks, I am encouraging the producers I import to consider switching to screwcaps. The use of screwcaps also allows the producer to add less SO2 at bottling, an obvious benefit. 

Dealing with Retailers

The most important step in finding the right wine to drink is finding the right merchant (or merchants) to buy it from. I trust my retail colleagues all the time to make decisions for me; I tell them what I’m looking for, give them a budget, and follow their advice. Get to know a few wine merchants, let them make suggestions for you, then tell them which were the hits and which were the misses. Part of this relationship, of course, is what happens when you think a bottle is off; if the wine is corked, they will certainly take it back, and they should listen to your feedback about wines you’ve had problems with, and in many cases will give you credit for bad bottles. I never take wines back just because I don’t like them, though.

Dealing with Restaurants

What should you do in a restaurant if you are served a wine that you think is defective? Most restaurants will take back wine under reasonable circumstances as they can return it to their distributor. Keep in mind that the reason you are invited to taste a wine before it’s poured for your table is to see if it’s corked or in some other way defective, not to see if you like it.

If the wine is corked, the restaurant should take it back with no question. As discussed above, cork taint at any concentration is always a defect. With any of the other defects, it depends on the kind of wine you have ordered. Wines that are made in the ‘natural’ style will not infrequently show bretty or oxidative notes. If you think you detect oxidation or volatile acidity, you should tell your server that you think the bottle may be oxidized and ask if it is a typical characteristic of the wine. Brettanomyces on the other hand is almost always a batch fault (meaning little to no bottle variation) and is furthermore a stylistic preference (you either enjoy it or you don’t). If you are sensitive to brettanomyces in the same way some people are sensitive to spicy foods or blue cheese, you may decide to tell the server the wine is affected by brettanomyces and it is not to your taste. Wines affected by brett are sometimes referred to as ‘rustic’, so you may also be able to avoid selecting a wine with brettanomyces or intentional oxidation if you tell your server or the sommelier that you want to stay away from wines that are too rustic or ‘natural’ in style.

Written By Oliver McCrum

February 17, 2016

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resources

The Oxford Companion to Wine, ed. Jancis Robinson

Wine Science, Jamie Goode

Wine Faults, Causes, Effects, Cures, by John Hudelson