Will Drinking Faulty Wine Make You Sick?

Have you ever been in a restaurant, hosted a dinner party, or sat on the couch with your partner and opened a bottle of wine? Of course, you have. Have you had a quick sniff of the first glass and thought – “hmmm, that smells a bit different” – but you’re not sure about it so you say/do nothing and drink away. Well maybe.

As many of you know I have spent a large part of my life learning about the wines of the world. I have visited several regions and always learn a great deal, both on a cultural and personal level. On my voyage of discovery, of course, I have experienced faulty wine and at times have been dubious about my own judgment. Believe me, in my insatiable desire to learn about vineyards, terroirs, grape varieties and the people behind them there have been occasions when I’ve shut-up and drank-up.

So when people ask me such questions as “how do I spot wine taint” or “will drinking faulty wine make you sick?” it brings me back to earth with a bang. It makes me realise that at times, we in the wine industry, forget that many people aren’t as intense about their wines as we are and obviously, their tastes are not as developed.

So the potential that a person might be served (or buy) a bad wine and not notice it is extremely intimidating to them, to say the least. They fear looking silly or worse, feel ripped off.


Ever thought you had a faulty wine but weren't sure? Here are 6 common wine faults:
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I feel that much of the fear is down to lack of knowledge (even a little bit) and therefore confidence. It’s our fault (no pun intended) for not explaining wine-related matters in an uncomplicated way. So, I’ve decided to write this post to try and explain, in a simple way, what could be wrong with a wine and how to spot it.

By the way, in response to the question in the heading – NO, is the answer. Faulty wine is not usually harmful, but it definitely won’t taste good. It may be unpleasant to drink but it is not dangerous.

Flawed Wine vs Faulty Wine

I have a link to a good article by the Australian Wine Research Institute later in the post which describes wine faults, taints, and flavours. However, before we get to that, in my own simple way, I would like to explain how I view the differences between flaws and faults. (In this post I may use the words flaws or taints interchangeably).

Imagine if everybody was exactly the same in that there was no such thing as an individual. Well, this isn’t realistic right? So for illustration purposes, I going to suggest that the small differences which make people unique (individual), are flaws – i.e. a little different from what you’d expect. Can you think of someone that’s a little different in some way? Of course, you can.

Similarly, in wine, a flaw is a minor attribute that departs from what is perceived as normal wine characteristics. Some people can handle it – others can’t. However, when a flaw becomes so pervasive that it is all you taste, that flaw is probably a fault.

There are many technical reasons for these defects and way too many for a casual drinker to remember. To make matters more difficult, being able to spot these flaws or faults is entirely up to the taste preferences of the drinker and/or their wine experience

To help you in this regard, one way of remembering it is, wine faults are internal i.e. related to the fermentation or the winemaking process. Wine flaws/taints originate from external or foreign sources.

For instance, a fault can be as a result of poor winemaking practices or storage conditions in the vineyard. It could be as a result of poor hygiene at the winery, or excessive or insufficient exposure to oxygen or sulphur. The winery might have used dirty wine barrels or used poor quality corks.

On the other hand, a flaw, or external source, maybe when a retailer has their wine display in direct sunlight or unsuitable storage or even using dirty glasses at a wine tasting.

Whatever the reason I tend to categorise them like this – a flaw may be just a quirk in personality whereas a fault may well make the wine undrinkable. How can you tell the difference?  Read on.

For starters – can I say that if you have any doubts about wine you purchase from Green Acres, don’t hesitate to talk to us about it. We’ll discuss what we think may be wrong and of course replace it if it is a faulty wine.

To help you identify some potential flaws/taints or faults, here are six of the most common wine faults and how you might spot them.

6 Most Common Examples of Faulty Wine

Just before we start can I point out that those little crystals on the bottom of a cork or the bottom of a bottle are perfectly fine. Without getting technical, these accumulate naturally if the bottle has been stored in a cool place for a period of time. This flaw is harmless and won’t affect you or the taste of the wine.

Now, do you know when the waiter in a restaurant opens the bottle and pours a drop of wine for you to taste? This is when you decide if it is OK or if it is a little dodgy – not whether you like it or not. So concentrate a little on what you’re doing. Get your nose in there and give it a good whiff, take a couple of sips and think about this blog post (eh, only joking).


This is the fault that everybody alludes to but it can be easily misunderstood. It means that the cork, even before bottling, has become infected with a chemical known as TCA. It’s a natural forming chemical on plants and is harmless at low levels. More and more, modern-day corks are treated for this early on so the incidence is becoming lower.

How to Spot it: – first up, it has nothing to do with little bits of cork floating in your glass. Sometimes you cannot even detect that something is wrong from smelling the cork. But, when you sniff the wine you will notice a smell like wet cardboard or smelly dog. Different people have different sensitivities to TCA so don’t be surprised if your drinking partner’s nose isn’t as offended. You won’t get sick if you do drink it, but a fresh bottle will show you what you’re missing.


Brettanomyces is a type of yeast commonly referred to as “Brett.” In winemaking, it is a yeast that’s everywhere in the air, on the grapes, in barrels, in the winery itself. It imparts an earthy aroma to the wines which most people enjoy. Too much of it though can make it taste like it was poured off the side of a horse.

How to Spot it: – Generally, smells and tastes like a barnyard—manure, stables, sweaty saddles, gamey meats, and also sometimes Band-Aids. A hint of leather or bacon might not be a bad thing but a full hit of manure – send the bottle back.


Just like it sounds – this is where the wine has been allowed to overheat. It can be from sitting in a loading dock at high temperatures, stored in a basement beside a heater or even in an attic or over a pizza oven. Pretty much this problem is due to the retailer’s lack of care (or knowledge). When I encounter this I always think of over-brewed tea. Constant temp is the key to storage –  so don’t store your wine in the attic.

How to Spot it: – it gives you a whiff of stewed fruit aromas from the wine or a raisin-like smell. One very obvious clue is where the cork sticks up out of the neck of the bottle (because the wine has expanded in the heat).


You know when you leave a sliced apple out on your kitchen table and it turns brown – this is the same process. It won’t spoil it immediately but in the long term, it’ll go off. Similarly with wines, if you leave your bottle of wine open for say a week – it doesn’t last and won’t taste too good.

How to Spot it: – usually you will notice a colour change. Reds will turn a brown or brick-red and whites will darken towards golden-brown. Smell wise, there might be a caramel-y taste of reds.


This is the opposite fault to OXIDATION above. During the winemaking process, the wine might not have received enough exposure to oxygen.

How to Spot it: – this is the one that people like to describe as the wine smelling of sulphur or rotten eggs. Sometimes I think of it as smelling of burnt rubber. If it is only a mild whiff immediately when you open the bottle, try decanting it as you will add oxygen in the process, which might solve your problem.


This is a hard one to spot as it occurs naturally in wine. It’s where the bacteria create acetic acid, which is fine (in small doses). But acetic acid is what gives vinegar its distinctive flavour.

How to Spot it: – you will definitely get a whiff of vinegar from the wine and sometimes the wine might actually taste like vinegar.

If you’re not sure about a wine, especially in a restaurant, indicate to the server that you suspect a flaw, not to your liking or a wine fault. Generally, they will take it back.


Well, there you go. I could write about many more flaws (taints) and faults but I fear I would start getting very technical. I mentioned above a good article about the subject matter from the Australian Wine Research Institutehere it is. It explains faults etc. in more technical detail than I have.

Also, here is a useful chart that outlines the smells associated with wine faults.

Wine fault Characteristics
Acetaldehyde Smell of roasted nuts or dried out straw. Commonly associated with Sherries where these aromas are considered acceptable
Amyl-acetate Smell of “fake” candy banana flavoring
Brettanomyces Smell of barnyards, fecal and gamey horse aromas
Cork taint Smell of a damp basement, wet cardboard or newspapers, and mushrooms
Butyric acid Smell of rancid butter
Ethyl acetate Smell of vinegar, paint thinner and nail polish remover
Hydrogen sulfide Smell of rotten eggs or garlic that has gone bad
Iodine Smell of moldy grapes
Lactic acid bacteria Smell of sauerkraut
Mercaptans Smell of burnt garlic or onion
Oxidation Smell of cooked fruit and walnuts. Also detectable visually by premature browning or yellowing of the wine
Sorbic acid plus lactic acid bacteria Smell of crushed geranium leaves
Sulfur dioxide Smell of burnt matches. Can also come across as a pricking sensation in the nose.

I really hope that my post will help you spot wine defects in the future. If in doubt, always ask another member of your party for their opinion or the server (in a restaurant). Feel free to contact me or drop-in to us here in Green Acres and we can discuss any aspect of your wine preferences and any special wines you would like to discover.

We look forward to engaging with you again soon – Cheers, Donal

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