Designation for by evaporation (Evaporation) resulting fluid loss in a wine container, especially in containers made of wood but also with nature cork sealed bottles occurs. In case of wood barrels is yes opposite tanks stainless steel. Glass or ceramics no absolute tightness given, but it takes place in both directions (both outward and inward) a certain exchange of substances (liquid and also oxygen ). With old wooden barrels can be due to leaks especially between the staves a relatively high shrinkage result. The resulting whitespace in a barrel depending on the type of wine especially at young wine regularly filled be to one oxidation to prevent. An influence also has the tightness of the spigot or the position of the bunghole on the barrel. Water and alcohol escape to varying degrees through the wood pores. In water molecules, this is faster, but also from the humidity depending on air pressure and air temperature.
High levels of moisture slows down the release of water but not alcohol, which results in increased alcohol relative to water loss. That usually means that in one wine cellar with ideally high humidity of 70% and more of the alcohol content reduced in the wine. In dry storage, on the other hand, the alcohol content increases. Internationally, especially in the spirits industry, the English term "ullage" for the evaporation loss of distillate used by the breathing wooden barrel. This is also poetically called " angels share ", Or in France as" part of the ange "called. The French term "ouillage" is used both for the disappearance itself and for the process of refilling. The loss in a bottle, however, is in any case on a leaky or defective cork or closure due. This results in a lower filling level, See also below aging. bottle aging and maturity,