At a recent tasting, I was presenting some sparkling wines from the Limoux region of France, a region that was producing sparkling wines at least 100 years before wines from the Champagne region were well known. Towards the end of the tasting, I commented that if the bottle is not empty and you wish to keep it, seal the bottle with a sparkling wine-stopper and store the bottle in the refrigerator. The immediate response was ‘Why bother to seal it – just put a spoon in the neck’.
I was somewhat surprised by this response as, although I had heard it suggested previously, I did not think that anyone took the idea seriously. From my years working on wine chemistry and wine oxidation, I know that making every attempt to minimise contact between wine and oxygen is vital for stopping the onset of oxidative spoilage. Thus, sealing the bottle is essential.
The source of bubbles in sparkling wine is the carbon dioxide released during the secondary fermentation. Carbon dioxide is more soluble in wine at a lower temperature, so storing the wine in the refrigerator is also beneficial to the opened bottle.
Searching the literature, I was amazed to see the number of claims that have been made for the ‘success’ of a teaspoon placed in the neck of the bottle. Some even claim that the teaspoon must be silver and not stainless steel, although the basis for this claim seems highly speculative. There have been a small number of limited studies that have tried to show that there is no difference in wine sensory perception between a bottle left uncovered and one with a spoon in the neck. Most lack replication and are often performed in a domestic setting.
It is essential to note some of the critical features of sparkling wine bubbles. In his book Uncorked, Gérard Liger-Belair from the Université de Reims Champagne-Ardenne demonstrated that the amount of carbon dioxide lost depends on the way the wine is poured into the glass: pouring into a tilted glass retains more carbon dioxide than pouring into a vertical glass. Using laser tomography (see April 2013 issue, p. 39), Liger-Belair was able to track the flow of the bubbles in a glass and separately showed that the bubbles are in fact aerosols containing aroma compounds that impact on the taster’s impression. To add to the complexity, the release of bubbles depends on the inside surface of the glass.
Bubble behaviour is therefore complex so that any study needs to be replicated to ensure that one is measuring a real effect and not an artefact of a one-off trial. One such study was carried out on champagne by Michel Valade and colleagues from the Comité Interprofessionnel du vin de Champagne (CIVC) in Epernay, France, and published in Le Vigneron Champenois in 1994 (copy in French available on request). The work entitled Le mythe de la petite cuillère (The myth of the teaspoon) was designed to address the claim that a teaspoon, preferably a silver one, could ‘defy all the laws of physics and possess some legendary efficiency to protect the bubbles escaping from an open bottle’ (my translation).
Three strategies were used by the CIVC researchers to assess the impact of ‘bubble conservation’ on the wine: the change in pressure, the loss of weight and sensory analysis. After opening, wine was decanted, leaving 500 millitres in one set and 250 millitres in a second set. The wines were then stored at 12°C with several methods to conserve the bubbles: open bottle, silver teaspoon, stainless steel teaspoon, cork stopper (hermetic seal) and crown seal. Each approach was performed in triplicate.
In the CIVC experiments, the initial bottle pressure was 6 atmospheres, dropping after decanting to 4 atmospheres (500 mL remaining) and 2 atmospheres (250 mL remaining), After 48 hours of storage, the pressure in open bottles and those with a teaspoon inserted in the neck had dropped by a further 50%, indicating a significant loss of bubbles. Clearly there was no teaspoon effect. Those sealed with a cork stopper or crown seal had a pressure drop of only 10%, demonstrating the significant advantage of using a proper closure.
To add to the evidence for the need to use a proper closure, the CIVC researchers also measured the change in the weight of the bottle after storing open, with an inserted teaspoon and with a proper closure. No decrease in weight was observed for the tightly sealed bottles, whereas for the fully open bottles and those with a teaspoon in the neck, the loss in weight was significant and the same for both methods.
To finalise the evidence to dispel the myth of the teaspoon, the wines were subjected to sensory analysis using tasters with experience in tasting champagne. All wines showed some characteristics of oxidation, due to oxygen ingress during opening. However, those sealed with a hermetic seal were clearly more effervescent and livelier than those unsealed or with an inserted teaspoon.
The authors of the CIVC study concluded that the laws of physics ‘are not broken’ and that the teaspoon effect is clearly a myth. So, if you need to store a partly used bottle, go and buy a proper sparkling wine stopper.