How to Identify Champagne Faults

The last thing anybody expects from a bottle of Champagne is a fault, but there’s nothing stopping even the most illustrious sparkling wines from developing the same faults as still wines. Even if Champagne’s unique production process and high acidity offer protection against some of the faults you might expect to see in a warm-climate red wine, the flipside is that the lengthy production process and delicacy of the wine does mean that faults do still occur.

TCA (Cork taint)

TCA, 2,4,6-trichloroanisole, is wine’s most notorious fault. Originating from contact with infected corks, it taints the wine with unmistakable mouldy scents – think damp dishcloth or wet cardboard.

Like almost all faults, TCA affects wines indiscriminately, old and young, cheap and expensive. Champagne producers and cork manufacturers have put serious efforts into eradicating it over the last ten to twenty years through innovations that include corks guaranteed a certain percentage TCA-free and, crucially, ‘technological’ corks that are 100% cork-taint free.

If, when you look at your cork, you see a single piece of fairly firm agglomerated material that springs back well after being removed from the bottle, you most likely have a technological cork, which will sometimes have the letters 'DIAM', and probably ‘Mytik’, printed around the top (see below left). These are produced by bonding together small particles of natural cork that have been treated with supercritical carbon dioxide to completely remove all traces of taint.

If, however, you see one or two discs of natural cork glued together, you have a cork that does carry a risk – even a very, very small one – of cork taint. The reason producers still persist with natural cork is that many believe that they are more effective for long ageing, and, as such, most vintage and Prestige Cuvées are still sealed with natural cork (see below right).


Corks 2

Other Cork Flavours

Contact with natural cork can sometimes produce slightly woody or damp flavours without the actual presence of TCA. This can mute or colour a wine in a negative way, although whether it is a fault may depend on its intensity. Wines that spend a long time on natural corks during the first fermentation are more at risk of these flavours.


There are Champagnes made in a deliberately oxidative way, and Champagnes where oxidation has been allowed to progress uncontrolled. It can be a little difficult to unpick the two, but if you have a champagne that smells of bruised apples, nuts or sherry, with little fresh fruit and a dried-out feeling to it, you’re encountering some degree of oxidation. If those characters swamp the wine and rob it of any pleasure, and the wine seems prematurely aged, then it is arguably a fault.

Volatile Acidity

Nail polish and vinegary aromas are signs of ‘VA’, or volatile acidity. This can be a more extreme manifestation of oxidation (the oxidation of acetaldehyde, the nutty-bruised-apple smell, leads to acetic acid or vinegary smells), but it can also originate in scenarios where grapes have been picked with an infestation of sour rot.


Champagne’s extreme climate does mean that in very difficult vintages, such as 2011 and 2017, harvests are sometimes taken in with some grapes in less-than-perfect sanitary state. Good producers will sort their grapes, although even top wines can sometimes carry off-notes. High volatile acidity, bitter, musty tastes and fresh mushroom aromas all indicate some unclean grapes.

Light Strike

Champagnes bottled in clear glass are vulnerable to ‘light strike’, which produces a compound called dimethyl-disulphide (amongst others). This has aromas that resemble cabbage and open drains. Light strike can develop in an alarmingly short time of exposure to light; just half an hour can reveal the signs.

Why do producers continue to bottle in clear glass in full knowledge of the risks? Partially, for the aesthetic. Many producers like to show off the beautiful colour of their wines – especially rosé – and, in the case of Louis Roederer Cristal (probably the most famous clear-bottled Champagne) there is a long-standing historical reason. Aside from this, there’s a level of denial around the issue, although the evidence is indisputable. Many wines come in protective sleeves, film or boxes, which should be kept on until the moment of drinking. These do not guarantee against light strike, though, which may have occurred before the wine was packaged. A safe rule is to never buy a bottle of Champagne (or any wine in clear glass) that has been sitting on a shop shelf – unless you like the smell of cabbage!

Wine in sun

Other problems

The funky, animal-like flavours sometimes found in extremely naturally-made still wines are rare in champagne’s low-pH environment, although they have started to pop up more frequently in zero sulphite and ultra-natural champagnes. ‘Mousiness’ is a fault that is impossible to smell, but only becomes evident on the palate (and usually the finish) of the wine, with a lingering musty, furry, animal-like taste. If you can actually smell an animally, musty smell, it might be Brettanomyces (‘Brett’, for short), a particular strain of yeast that lingers in barrels and produces off-aromas.

What should you do if you think a wine is corked or faulty?

Many wine lovers are reluctant to call out all but the most obvious faults in wine but, if you do sense something is off it’s always worth flagging rather than battling on with an unenjoyable wine. In restaurants, sommeliers will usually be happy to taste the wine and replace it if they too find fault. With retailers it’s more varied but, at Sip we are happy to replace any bottle that is damaged. All we ask is that you take pictures of the front and back label and the cork and email us ( with the issue you have identified. 


Thank you Peter. Extremely useful. Just to share, a couple of problem bottles I’ve had in the past have always been replaced, without question which is good to know.

Tony Juneja September 29, 2023

A very well written and informative piece.
It is good to share information about the ‘Usual suspects’ that can interfere with the enjoyment we expect from champagne.

Raymond Tilney August 15, 2023

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