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Versión Español

- PUBLISHED IN THE MAGAZINE "OENOLOGIST" SEPTEMBER 2002 -



Paolo Trappolini


PREAMBLE
INTRODUCTION
THE PROBLEM
NECESSITY
RESEARCH
RESULTS
USAGE
IMPACT WITH THE MARKET
THE STATE OF THE ART
ECONOMIC ASPECTS
CONCLUSIONS


•PREAMBLE

I am an oenologist, and not a researcher so my contribution to this appointment is based upon my own experience acquired during my work in the winery and it refers to the technical, practical, and commercial aspect of “synthetic” cork use.

I thought to focus my attention on this alternative why being a consumer of wines I feel embarrassed to come across a classical “corked” taste, especially when the wines in question are mine.

The conventional cork is a natural product, and in this sense it can cause problems related to a large number of factors.
For this reason there is a certain tolerance regarding this imperfection of natural corks, announced by manufacturers and accepted by users.

But very often this tolerance is a long way overpassed.

•INTRODUCTION

So by paying my attention mainly to safekeeping the characteristics of wine I tried to analyse those features of the natural cork that could alter its quality. A necessary introduction to be made is that I am entirely devoted to three names wine-glass-natural cork, either from the emotional point of view or from the strictly technical aspect.

I believe that a natural cork contributes to give a particular charm to the wine, and each time I watch with attention and renovated enthusiasm the ceremonial of opening a new bottle.

Technically, I think that a natural cork (a good one) is an ideal closure for each kind of wine regardless of its “precious” or “commercial” value.

The high quality of it depends essentially on physical and mechanical characteristics that make it suitable for this purpose, and what’s more they have been certified in the last decades.

But what I am perplexed about is something else. It happens often that its chimical (and sometimes structural) characteristics are altered by treatments that the natural cork undergoes in the phase of transformation.

•THE PROBLEM

The problem is that nowadays the natural cork not always appears to be safe and it becomes even less safe in the long run for different reasons.
One of the reasons has to be searched for in the evergrowing demand met always by supply using often the raw material of doubtfull origin which not always satisfies minimum quality requests.
All the corks go through these problems, but especially those of low and medium quality range.
After tests conducted upon mono piece of cork we have deducted that the major problems arise within purchasing margins going from 250 to 550 lira.
Having excluded the use of corks of inferior range, we verified that such a kind of inconviniences seems to be reduced upon growing of purchasing costs, that’s to say for values superior to 600/650 lira.

If we want to speak about problems, I refer not only to the “corked” taste by itself but mainly to the defects trasmitted to wine by the cork that cannot be traced.

When the wine has the “corked” taste, it is rejected but when a cork alters the wine in the other way (often chimically) the problem becomes more serious and difficult to track.
It happens often that some defects are attributed to the wine that do not actually come from it.
The defects that are quite easy to recognize, more o less serious, that are used to be spotted only by those who knows that wine. There are defects that are caused by the cork but not attributed to it.
And here comes a surprise and perplexity of a consumer that upon opening two or more bottles of the same wine sometimes descovers them to differ one from another despite coming from the same lot or the same bottling.

So the doubt arises that casts a shadow over a winery which besides the demage produced to the product and to the image is penalized because of the critics of a consumer.
Not to mention the work, costs, and time spent for each single bottle of wine that run the risk of resulting vain owing to the cork.
I will never forget a degustation dating back to some years ago at which those that were considered to be the best merlot of the world.have been tasted and compared.
One of the wines representative of France was PETRUS (’93) held to be one of the most important wines of the party.
In view of the high price of it only one bottle was purchased. I remember clearly as if it had happened now the disillusion and disappointment I felt that you could read also in the eyes of other participants at percieving the irreparable “corked” taste.
On that occasion the bottled was paid 980.000 of old and precious liras.

•NECESSITY

Here comes the need to make an attempt to find a solution.
Especially, since the problems related to corks used on basic wines increase, a few years ago I was forced to search and evaluate the possible alternatives to the classic natural cork in one piece.

What I had in mind was a secure and reliable cork with no olfactory, gustatory or technical problems or even better
with the right relationship between quality and price.
So I took into account all the alternatives that the market could offer at that moment between them the one of synthetic cork.
I don’t deny that my approach was occasional and I came up to it with great scepticism.
I would have never thought that one day I arrived to use it.
I was considering it to be disqualifying for wines and for the image of the winery. Not fit for the function it had to perform, completely disconnected from the enological world, difficult to adopt and noxious for wine.

I devoted my attention mostly to the various alternatives that the world of a natural cork could offer.
After the first trials I was surprised to notice that while the wines closed with natural corks and technical corks continued to cause problems of different character those closed with some types of “synthetic” corks were either free from defects or at least did not present problems that couldn’t be solved.

•RESEARCH

In view of all these facts I made a start submitting them to some tests aimed at drawing a comparison between technical, mono piece, synthetic corks and even of screw caps. All of them delivered by different suppliers.

My objective was to descover the most suitable sealing system for fast, white and red wines that were supposed to be consumed within 2-3 years.
Over natural, mono piece, technical corks were conducted mechanical and chimical controls. Primarily we controlled the following parameters:

Weight of cork
Dimensions
Specific weight
Cylindricity
Esthetical design (entirely suggestive parameter related to one single reference sample)
Quality of printing
Percentage of pores present on the surface and above heads
Capillary absorption of the wine
Peroxide presence
Sensory test
Sealing pressure
Extraction force
Elasticity of a cork after opening the bottle

We took into account also a cost.

As far as synthetic corks are concerned, we were not able to make all the difficult and intricate controls that refer to the release of dangerous to health and to the wine chimical molecules we rely upon results obtained in universities and research institutions ordered by different manufacturers.

What we did in the winery was to repeat applied to the synthetic cork all the analysis made on the natural cork.

Obviously, after some controls we excluded some tests such as porousness of the surface and of the head or aethetical appearance introducing instead other tests such as immersion of the whole or cut piece in acid and hydro-alcoholic concentrated solutions to reveal if there were any alterations in the structure or anomalous gustative releases.

No controls were carried out on screw-caps used for sealing the testing wines.

It was intended following the common procedure to seal a certain number of bottles of white and red Bodolese with the previous control of the bottle’s neck and opening them at fixed expiry dates for chimical and sensory comparison tests.
Since the time of consumption was roughly assessed at 2-3 years, but some bottles were likely to be kept even longer, our tests continued for 4 years (and they are still ongoing).

•RESULTS

Quite interesting data followed.
It is obvious that unaltered wines resulted those closed with screw cap closure (with plastic or natural cork basis).
As for different types of natural cork close to those in perfect conservation state there were some more or less altered.
The most frequent defects represented the gustative modification of wine traceable exclusively in the direct comparison with bottles sealed with screw-caps.
The synthetic corks produced results of uneaqual character in consideration of a large variety of suppliers and very regular results within delivery limits of each single supplier.
The defects found on synthetic corks were verified within a couple of months and were mainly dictated by:

- Difficulties of extraction of the cork from the neck of the bottle caused by low plasticity grade of the cork that required consequently an excessive force.
- Rotation of the cork inside the bottle’s neck or even its falling inside the bottle when the pressure adopted for unsealing was too high. The reason is an excessive lubrication of the cork.
- Spontaneous exit of the cork from the bottle’s neck while exposing the bottle to intense colour sources that tended to increase the volume of wine or the use of it on sparkling wines ( a kind of problem typical also of some natural corks)
- Major scratching risks in the bottling stage.
- Wine oxidation
- Release of plastic flavour
- Alteration of customer’s trademark design
- Negative psycological impact on persons called to evaluate wines.
As for the release of dangerous to health and to the wine chimical molecules as I anticipated in the introduction part we trusted the research results obtained by others that actually didn’t confirm the presence of them.
I am absolutely aware of the fact that the discovery of some new molecule not known till now could stir up a new discussion about synthetic, natural and technical cork.
Along with these discouraging results there were also those positive.
Actually we came upon some types of corks that did not alter the quality of wine that could satisfied our requests.

And we start to work at them.

•USAGE

In the meanwhile, the industry probably encouraged by the growing interest began to move towards this new technology.
Since to handle the synthetic cork is more easier and faster than a natural one, new elastomers that met the requirements of the enological field in the best way have been worked out, tested, manufactured and introduced into the market.
So far we are enable to learn about the exact composition of different corks because the manufacturers keep the secret with great care.
At any rate, the raw material for their production are based substantially on injected acetylene vinyl, on polyethilene, polypropilene and elastomer rubbers with the adding of different expanding materials (azodicarbonamide type – on a starch basis – or endothermic type – on a basis of citric acid and carbonic acid).
Today to assure the major elasticity some types of corks are made with various grade of density.
New lubrication methods have been adopted to reduce the slippery effect.
The employed materials are perfectly neutral in relation to flavours and smells.
New inks approved for the use in contact with food have been introduced for the printing of a cork.
And another important point is that there was an increase of production to the extent that it allowed to lower the prices, that at the beginning were quite high.
Consequently, the winery had to conform with this type of cork bottling for instance ready wines or to conform the bottling facilities.
It is required for those who use a technological cork the empoyment of vacuum system pusher to avoid the dangerous oxidative effects that otherwise would happen or, even worse, that would require the use of excessive quantity of SO2.

•IMPACT WITH THE MARKET

At this point we have to tackle a bigger problem how to reduce to minimum untill concelling at all the “negativity” of psycological impact on the consumer in front of the plastic cork.
It took not indifferent efforts also for us “to accept” such a material being so far from that one that used to be a part of our “traditions’ luggage” the natural cork.
And therefore, after a long and careful assessment we decided to try to introduce these corks on the market in 1996.
We put in act a huge initiative of tasting of wine in 52 restaurants and enoteques and also in three restaurants abroad.
The procedure we adopted was to let the customer taste the same wine sealed with synthetic and natural cork asking for their opinion about the quality before revealing them the fundomental difference.
Moreover, customers recieved a questionary to fill up in which they were asked besides other things how they felt about synthetic cork
The choir almost unanimously disapproved the synthetic cork.
Few persons were in favour of them, and there was also someone that didn’t take any position .
So our test ended up proving that the market wasn’t ready to accept new stoppers.
We had to take another alternative way.
On that occasion we bottled around 500 btg of White Avignonesi and as much of Red Avignonesi.
It wasn’t a big quantity, and we knew that we would sell them, but we also knew that we would never do it again.
All that wine went in Germany.
Within a few months it was an outright surprise to us to recieve requests of wine from Germany corked with synthetic closure.
At that point we made all the appropriate adjustments while carrying out the order to draw attention and to put in evidence the use of these corks.
For that purpose, we adopted vivid colours and even applied on bottles a colar label to attest the use of “PILLO” cork (the name that the company gave to the synthetic cork).
Afterwards we used trasparent crown-caps on bottles of white wine to exhibit the yellow cork.
Nothing should have gotten an idea that we were imitating a natural cork.
There was a difference and we had to put it in evidence.
Starting from that moment Germany first of all along with other countries Italy inclusive will opt with growing preferance for wines sealed with synthetic stopper instead of the natural cork.
For a year we let the client choose personaly among both types of cork.
When a demand for a synthetic cork exceeded the request of natural cork, it was taken a decision to get rid of the last one.
Such a choice was likely to cause the lost of some clients but that didn’t seem to be a qualifiable result.
What is sure is that three types of wines upon which was used PILLO cork revealed an increase in sales and never more gave pretext for the customers for raising objections.

•THE STATE OF THE ART

At the moment the sales of a synthetic cork go round 200 millions of pieces (data delivered by a supplier related to 2001)
At the winery of my competence around 50% of total production is bottled and refer to wines classified within the segment of the market I mean the prices at the enoteque varying from 7 to 9 Euro.

The wines are:

WHITE AVIGNONESI I I.G.T. Tuscany,
RED AVIGNONESI I.G.T. Tuscany,
RED OF MONTEPULCIANO D.O.C. (an example that it is also used upon d.o.c. wines)




Its appearance on the market didn’t bring any complaint neither from clients nor from the importers.
And we solved many problems of storage.
We manage to keep under control prices that not only stopped growing but it happens that they are on the decrease.
These stoppers were not used upon wines classified in the high segment of the market for various reasons:

1. Some production descipline regulations like the one for Noble Montepulciano Wine ban them.
2. Since we are not in possess of experience of these corks’ use major than 9 years, and we cannot guarantee their validity on wines that are supposed to be consumed after this period.
3. Since the incidence of a natural cork defects are much lower on extremely expensive natural corks that are used to be empoyed on these wines.
4. Since it is right that a certain market accepted these corks on wines of medium market segment that are often served and sold by glasses we are not quite sure that the market “of high scale” is so mature as the medium market.
Anyway at our cellar we have been carrying out for years appropriate testing on more important wines just to be ready for their use in case of need.

•ECONOMIC ASPECTS

Many times we were accused of having used these stoppers only because of their economic benefits.
That is not right.
Their cost at least at the initial stage was not lower that the cost of natural corks.
Nowadays you can find also low-price economical stoppers, but I’like to focus your attention on final results.
The fact that there is a lot of talk about the synthetic stopper doesn’t mean at that all of them are univocally valid.
Also in this sphere in fact we noted a plenty of manufacturers to boast about excelent quality but when in practice causing not indifferent problems.

•CONCLUSIONS

Finally, further to my modest professional experience I find a synthetic cork to be a valid alternative to the natural cork especially for the low and medium market segments.

Obviously it should be carefully selected between available alternatives that are being offered submitting them to previous accurate controls at the winery.
Besides, I hope that the use of the synthetic cork that nowadays is taking away from the market of conventional cork important numbers will incite the natural cork manufacturers to improve the quality and reliability of their products.

Paolo Trappolini



AVIGNONESI SpA winery gave its preference to SUPERCAP® cork

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