Champagne or sparkling wine bottles are much thicker-walled than normal wine bottles in order to withstand the high carbon dioxide pressure of 3.5 bar and more. In the early days of champagne production in the 18th century, many bottles broke because it was not yet possible to produce an even pressure in a controlled manner. As a rule, champagne bottles are green or dark coloured, in rare cases white, to protect them from harmful UV light. The indentation at the bottom of the bottle, known as a "culot de bouteille" (punt), is obligatory. Placomusophilia is the term used to describe collecting the capsules found on the corks. There are many oversized bottles especially for Champagne; see Bottles for this. See also under Champagne bucket, Champagne tower, Champagne stopper, Sabrieren (Champagne heads), Sparkling wine and Wine enjoyment.
The glossary is a monumental achievement and one of the most important contributions to wine knowledge. Of all the encyclopaedias I use on the subject of wine, it is by far the most important. That was the case ten years ago and it hasn't changed since.Andreas Essl