Why wine bottles have a punt under?
The wine exists since prehistory , but the glass bottle did not appear until the seventeenth century, when the fermented drink became a product for the upper classes worthy of celebrations and banquets. The subsequent appearance of champagne forced its producers to improve its design and make it more resistant to the pressure of carbon dioxide, but that is not the only reason why today they are still making bottles with their punts in the bottom. Actually, there are many reasons why this is done; almost all historical.
Before the appearance of the glass, the wine was more exposed to oxygen and should be drunk soon, because otherwise it would oxidize. The glass bottle allowed the drink to be stored for a longer period of time and made the wine taste better. At the beginning, the bottles were made by hand using the technique of blown glass . They were green due to the impurities of the material, and had slightly different sizes due to their artisanal nature, so their capacity ranged between 70 and 80 cl . But the real reason why the punt was included was to hide the point from which the bottle was blown.
When the glassblower blew the bottle from the bottom, it left a bump in the bottom that could scratch a table or make the bottle unbalanced. A container with the flat bottom only needs a small imperfection to wobble, and the bottom in which the glass was blown was the perfect candidate. As a solution, the bottles were designed with the convex bottom, a design that prevailed even after H. Ricketts & co. Glass Works Bristol patented a way to manufacture the bottles mechanically, eliminating the bump problem.
However, the curved bottom of the wine bottles (which in Spanish is known as “picada”) fulfills more than one function . One of them is to distribute the pressure inside the container to withstand the hard process of corking and, especially, the high pressure of sparkling wines. The curve also adds weight to the bottom, which makes the container harder to knock down. In addition, it prevents the glass from cracks, which decreases the likelihood of the bottle breaking during transport; and facilitates cleaning by spreading water more evenly throughout the bottom of a bottle that has punt.
The same effect comes into play with the sediments of the wine. Punt lets sediment collect in a tight area near the base, stopping the sediment from blending back into the wine as it’s being poured. Finally, the design allows to better stack the bottles, produces the sensation that the container contains more liquid and yes, allows the sommelier to hold the bottle more easily while explaining the benefits of the wine.