The Heidelberg Tun is a very large wine barrel1, 2. It stands in the cellar of Heidelberg Castle, which is located near the city of Heidelberg in Germany. The Heidelberger Tun is a lot larger than the offical Tun of wine, which is equal to 4 hogsheads or 953.92 litres3, 4-indeed, it's about 230 normal tuns of wine, or 220000 litres1.

The Heidelberg Tun was built in 1751 by Prince Elector Karl Theodor to house wine paid as taxes1. However, the Tun was only rarely used to hold wine. The present barrel is not the first Heidelberger tun; in total, there have been four 3, 5, with the first being built in 15915, 6.

It is interesting to note that using a huge barrel like the Heidelberger Tun rather than normal wine barrels will have an impact on the wine stored in it. In normal oak barrel, some of the water and alcohol in the wine evaporate. This is known as the Angel's Share. This does have the effect of concentrating the aroma, so it may improve the taste of the wine. Furthermore, tannin from the wood dissolves in the wine, altering its taste. The diffusion of oxygen through the slightly porous oak also changes the flavor of the wine. In a huge barrel like the Tun, the surface area is relatively small compared to the volume. Mathematically, the surface increases with the square of the barrel size, while the volume increases with the cube of the size. This means that relatively, there is a lot less evaporation in such a large barrel than in normal barrels7.

Presently, The Tun serves as a tourist attraction, as part of Heidelberg Castle, which itself is also a tourist attraction5. It is, of course, a rather unique site: Although larger wine vessels may exists, these are much more modern and I assume they are not made of the wood of 130 oak trees 3, or have a small dancefloor, reachable by stairs contructed on top like the Tun3. The castle also houses the Apothecary Museum, which is about the history of pharmacy1. Together with the castle ruin and the garden, it is one of the reasons Heidelberg draws over a million tourists a year8.

Sources

  1. http://www.tourism-heidelberg.com/explore/historical_sights/schloss_heid elberg/index_eng.html
  2. http://www.britannica.com/EBchecked/topic/259532/Heidelberg
  3. http://en.wikipedia.org/wiki/Tun_(unit)
  4. http://www.google.com (Google Calculator)
  5. http://www.heidelberg-marketing.de/content/e553/e855/index_eng.html
  6. http://www.inyourpocket.com/germany/frankfurt/feature/55532-heidelberg.h tml
  7. http://www.nationmaster.com/encyclopedia/Aging-barrel
  8. http://en.wikipedia.org/wiki/Heidelberg_Castle