Clear-Glass Bottle Protection

CLEAR-GLASS BOTTLE PROTECTION

Since 2015, every bottle of Champagne or sparkling wine that is entered into our competition in a clear-glass bottle is “double-bagged” in black plastic as soon as it is removed from the packaging in which it is delivered. This is our commitment to ensure that no wines are affected by ‘light-struck’ aromas due to contact with artificial lighting or daylight whilst in our care.

In our first year we had a disproportionately high number of off-odours from clear-glass bottles. Just 60 minutes under artificial lighting or daylight in any clear-glass bottle can ruin a wine, particularly if it is a sparkling wine.

The scientific reason for light-struck aromas

The primary culprit is an unpleasant compound called dimethyldisulphide (DMDS). At its very worst, DMDS smells of stagnant water, old drains and sewage. At lower thresholds, it merely inflicts an otherwise fresh wine aroma with the barest hint of rotten cabbage or something unclean, similar to a very slight mercaptan aroma. Although DMDS can be formed in other ways, this compound is most commonly found in wine when a sulphur-bearing amino acid called methionine is broken down by exposure to ultra-violet (UV) light.

According to studies, UV can degrade methionine into DMDS after just >60 minutes exposure to fluorescent light, while other research has shown that carbonic gas accentuates the odour of this compound.

Our plea to producers – PLEASE STOP USING CLEAR GLASS

Clear glass is commonly used for rosé and blanc de blancs Champagnes, including some of the very highest quality cuvées. Whatever the producer does to safeguard his Champagne from DMDS while it is within his own production facilities, he has no control over its exposure to light once it has left his premises. (Protective wrappings are more often than not removed by consumers who like to see or show off their bottles and the more attractive the bottle the more likely it will be placed in a position of high visibility and thus exposed to light.).

We would like to see Champagne and sparkling wine producers stopping using clear-glass bottles.

The tired, old excuse is that it is demanded by the marketing people. Clear-glass bottles can be gorgeous, so we sympathise with the marketing people, but not their employers. This is a quality issue that threatens reputations and any producers who allow their marketing people to interfere with such a crucial quality issue deserve to have their reputation ruined.

We will caution consumers to buy clear bottles only if and where they have not been removed from their packaging, and we will advise consumers to store clear-glass bottles in the dark and to keep the bottles not just in their protective wrapping, but also in the original packaging.