I have borrowed this from one of my favorite sites, please follow the link below...
From Jancisrobinson.com
Julia Harding MW, currently hard at work on the viti and vini entries to be published in the 3rd edition of The Oxford Companion to Wine due out in sep 06 kindly went to a symposium on wine faults so that you (and I) didn’t have to. Here’s what she learnt (surely required reading for all 85 candidates in the Master of Wine exams next month).
Bored with discussions about closures and tainted wine? Read no further. Want a summary of the main faults and their causes, plus some surprising statistics and aebstruse abbreviations? Read on…
Much of the information below derives from a seminar and particularly unpleasant tasting (nosing) of spiked wines led by Pascal Chatonnet in London last month in the grand but oddly subversive environment of the super-smart Sanderson hotel. Arranged under the auspices of Amorim, the leading cork supplier, the unhidden agenda was to point out how many wine faults could not be directly attributed to cork. Various samples of a (once) fruity southern French vin de pays had been spiked with chemical compounds, at different concentrations, to replicate the effects of a range of wine faults.
Before looking in detail at east of these faults, here’s a summary of some of the more interesting snippets to emerge.
- In a trial conducted by Southcorp in Australia involving 150,000 corks over nine years, the overall incidence of different types of cork taint was just 1.84 per cent. Of this, 1.5 per cent was due to TCA, according to the ANZWIJ article referred to below at *.
- TCA and other taints are more evident in sparkling wines and champagne because the taint compounds are volatilised by carbon dioxide.
- Oxidation may either increase or mask TCA.
- The compounds described below only become taints at or above perception threshold, depending on the compound and on the sensitivity of the taster. You may like a little Brett in your wine?
- The more often you smell a wine tainted with TCA, or any other fault, the less severe seems the taint because of the very significant effect of habituation.
- Perception of cork taint is exponential, not linear, so if wine A has 6 nanograms per litre (ng/l) of TCA and wine B has 12 ng/l, wine B will not smell twice as bad as wine A. The very severity of the taint starts to inhibit its perception: the brain reduces the intensity of perception as the concentration increases.
- Wine may be contaminated indirectly through products used in the winery other than cork. For example, bentonite stored in a winery where the environment is contaminated can then affect the wine during the fining process.
- Synthetic corks can be contaminated with TBA if they are transported or stored in a contaminated environment.
- Corks produced from cork bark close to the ground are more likely to give rise to TCA since there is a greater likelihood of fungi such as penicillin near the base of the tree. This is another reason why cork bark should not be stored in direct contact with the ground.
- Thus far, TCA and TBA are organoleptically indistinguishable.
Me:
There is an exhaustive index which continues listing more complete informationon TBA, TeCA, PCA, MDMP, IBMP and some fascinating information on incidence of Brettanomyces, but I believe it is only available to subscribers. Come to think of it, why aren't you a subscriber?
There is no doubt that many of faults we call "corked" are actually other problems. There are many bottles we taste that there is just something "off" and this happens more than bottles that are clearly affected by TCA. One thing is clear and that is about 5% of the wines sold are faulted in some way and less than 1% of those wines are being returned by consumers. This, of course, means that they are drinking them, often without perceiving any problem or just thinking that winery "X" just doesn't make very good wine.
Posted by: Craig Camp | May 10, 2005 at 11:13 PM