
Oval Wine Tanks
June 2025


Having a brother and sister-in-law who enjoy food and wine is great. She, being an excellent photographer, emails me photos of what they have experienced and seen. Recently, they visited wineries in the eastern French wine region of Châteauneuf-du-Pape, along the southern Rhone River. Here is a photo she sent of six elegant oval oak casks sitting quietly in one of the winery caves.
Look at the casks in these photos closely. Besides their elegant stature, the artisanry is amazing. For example, in a wine or whiskey barrel, the angles on the staves vary, but in a direct ratio to the width of the stave. In an oval, the angle changes not only depending upon the stave width, but its position, whether it is on the top or bottom or on one of the sides.
Further, given the larger sizes of many of the casks, the staves can’t be bent over a fire; they must individually steam heated. Once the wood is sufficiently flexible, it is placed in a template to set it in the correct curvature. Since steaming provides a different organoleptic profile from bending wood over an open fire, some are subsequently assembled without the ends and set over small fires to ‘toast’ the oak, a process that can take a full day.
When all the pieces are ready to assemble, the bottom staves are placed within two cradle-like bases. The cask’s ends are then set within the croze of those staves, propped up to hold them erect as the remainer of the staves are positioned, adding first the sides and working up to the top. All these steps in their fabrication, plus sizing the hoops and cutting a door, are time-consuming, adding to their costs.
Both an oval cask and a wooden tank can hold more wine per volume of space than a barrel. Thus, they are used to store larger quantities. But an advantage of the ovals versus round tanks is their efficient use of the space, especially in caves with low ceilings. However, in both shapes, the larger volume, as compared with barrels, reduces the wood contact as the surface area for the wine to interact with the wood is minimized.
Another advantage of an oval cask is that as the wine evaporates, the surface area at its top becomes only very slowly larger, like a barrel. Whereas in a flat-topped wooden tank, once the wine level drops below the top, suddenly a huge surface area is exposed, creating the potential for oxidization. If the tank is not topped up frequently, the cover can dry out, allowing air to enter.
Another advantage is that they look really cool in a wine cellar.
Oval casks are and have been crafted in a range of sizes and uses. Some, in the one- to five-litre range were built as elaborate displays to be set upon a bar or restaurant cabinet for dispensing port, sherry, cognac or other spirits, or cordials. Others are in the 200- to 400-litre range to mimic barrels in their ageing characteristics. Typically, the ones now used in wineries are in the larger 1000- to 5000-litre range (as shown in the photos above).
One of the largest oval casks in the world is in Germany, set deep within the cellar of the Heildelberg Castle; the Heildelberg Tun. Now in its fourth iteration, this one having been built in 1751 because the previous ones were burned or otherwise destroyed, it could hold over 200,000 litres. It is so large that a dance floor was once built atop of it. No longer used for wine, it functions as a tourist attraction within the castle.