Wednesday, June 14, 2006

How to tell that this wine is spoiled?

It is pure coincidence that I tasted two spoiled wine in a row within a week. One customer asked me the characteristics of a spoiled wine and how to recover from such unpleasant experience. The short answer is that sometimes it is a good idea to taste some spoiled wine so that we know what it is like. To recover your fresh palate, the best way is to gaggle with a pint of room temperature water and let your palate settle down before going for a new glass of wine.

So, how does wine spoilage come about? There are two possible causes – chemical spoilage and microbial spoilage. Chemical spoilage is mostly contributed by careless treatment of the wine that results in excessive addition of chemicals such as sulfur dioxide. Legal bound of free sulfur dioxide during bottling is not more than 25-35 ppm. Remnants of carbon dioxide during bottling will also cause a “spritz” feeling on the tongue. In most cases, this sensation is not desired and should be eliminated. Sometimes, if the smell of rotten eggs, sewage or garlic is found on the wine, it is most likely due to the untreated hydrogen sulfide which could later be transformed into mercaptans and disulfides.

Microbial spoilage is a result of undesired growth of microorganisms in wine. Factors such as pH, temperature, residual sugar, nutrients, oxygen will affect the growth if they are not controlled within the range. For example, the presence of oxygen during fermentation will encourage the growth of acetobacter, a bacteria that is always present in wine. It starts to propagate by consuming alcohol and produce acetic acid and ethyl acetate. A little acetic acid contributes a small sensation of sharpness to the throat. Too much of it will be very undesirable and considered a spoilage. The ethyl acetate is generally present in late harvest wine, responsible for the unpleasant, pungency smell. Since this bacteria is inherently present in the wine, sulfur dioxide is not able protect the wine against acetobacter. The only way to prevent their growth is to minimize their contact with air (oxygen) and keep the wine cool (e.g below 10C).

Therefore, when we happen to taste a glass of spoiled wine, the unpleasant mouth feel is an indication of its winemaking as well as storage conditions. The color and smell of the wine usually give away information of its quality before it is even consumed. An oxidized wine is brownish in color (if it is a red) and has the unpleasant pungency nose. Its taste is acidic, perhaps reminding you of vinegar, leaving behind a trail of stuffy sensation in the throat. In case we have the honor of drinking such wine, it will be an eye opening experience that adds to our palate memory, inspiring further exploration in the world of wine.

Reference: Dr Yair Margalit (1996), Winery Technology & Operations published by Wine Appreciation Guild.

Updated article on:

By Cher Lim
Wine Treasures Pte Ltd



Blogger DesDragon said...

Wow, great detail in the write up.
You must be a really passionate wine fanatic!
I have a blogsite also dedicated to wine, do take a look when you have time! Cheers!

Tue Jun 27, 03:14:00 PM  
Anonymous NationalArise said...

I was wondering if you could help me...
I have a bottle of wine froma a few years ago. I'm not sure if it is no longer good. it's called Nostradamus. it comes in a very dark, almost black, triangular shaped bottle. it says its made from cabernet sauvignon and merlot grapes. i don't see the year it was bottled. Out of curiosity i opened it. the first thing that struck me was the aroma.. the first descricptive words that come to mind are.. carmalized and berry/fruity. I tried a little bit and as fr the taste, its not very.. robust as you will, and kind of sweet. there is no harshness or 'spritz' to the tongue not 'stuffiness' of the throat.
i've tasted not nearly as many red wines as you have, i'm sure. =) but i have had a few. i make it task to get a different kind of red wine every time i get wine. i'm am kind of curious though as to if this wine is still good and if there are any repercussions to finishing the bottle.

Please e-mail me back with your best judgement. You or anyone else that might know that happens to read this.

(Please e-mail me at:
with the subject line of:
Spoiled Red Wine)

Thanks a bunch for your help!!!!!

Tue Dec 11, 04:36:00 PM  
Blogger Cher Lim said...

I sent a mail to pepper_ann_420 but it get bounced back. So, I thought it should be alright to answer here. It is hard to tell the quality of wine from your description. However, it does look like a custom made bottle for a small distribution (it is not common to see triangular shaped wine bottle!) If there is no indication on the bottle about its product of origin, vintage, alcohol level, Sulphure Dioxide level etc, it is best to approach the subject with caution unless you are sure that it is from a trusted source.
To tell a wine if it is good without laboratory tests and the palate test, I would include the following in my checklist:
a) Storage history: Has it been stored properly in a cool place?
b) Visual test: Upon opening the seal, is the cork still firmly seated at the bottle opening?
c) Visual test: Is there any wine stains at the top of the cork surface?
d) Visual test: After removing the cork from the bottle, examine the cork condition - is it clean or has dirty wine stains soaked the entire cork?
e) Appearance of wine: When the wine is poured into a wine glass, we should check if it is clean or murky. The latter is not an encouraging sign.
f) Color of wine: If the color is unusally light (for red) or brown (white), there is a chance of overusage of sulphur dioxide but this is not conclusive. It is only a possibility.
g) Nose test: Now, you can smell for any odd odour e.g rotten eggs, wet cardboard, bandaid, matchsticks .etc All these suggest wine faults
h) Taste test: Finally, the taste will give the final conclusion if the wine is spoiled - if the wine attacks SHARPLY on any of the 5 taste sensations, and you are in doubt after going through the above steps, it is better not to drink.

Please bear in mind that excessive use of sulphur dioxide may not be detectable for the untrained drinker and if the bottle has no information on these data, it is better not to consume.

Hope this helps,
Cher Lim
Wine Treasures Pte Ltd

Fri Dec 21, 08:50:00 AM  
Blogger candice said...


I make wine at home, the usual port wine kinds made out of raisins & fresh grape.

I have a couple of close family members and friends who religiously ask me to make wine for them for the festive season.

Recently, i've got them requesting me to give them the wines that I have been saving up bottle by bottle over the years. Ive got some homemade wines thats over 3 yrs old. To me, they taste fine. but i was worried about the preservation bit and wanted to know if wine aged in common household conditiones is safe for consumption.

This is important for me to know, since i do not want any body falling sick.

Bottling: I do not distill the wine i make, i only strain, color and bottle the wine in clean and dry alcohol bottles that ive been using over the years(eg. old monk, rum bottle)

kindly suggest.

Tue Nov 10, 03:42:00 AM  

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