Ullage (from the French ouillage ) is a wine-making term that has several meanings but most often refers to the air space between the wine and the top of the vessel holding the wine. It can also refer to the evaporation process that creates the headroom itself or can be used as a past verb to describe the wine barrel or bottle that has gone through the evaporation process ( to blisters , etc.). The air space is a mixture of mostly alcohol and water vapor with carbon dioxide which is a by-product of the fermentation process. In containers that are not entirely airtight (such as oak vats or wine bottles cork blocked), oxygen can also seep into this space. While some oxygen is beneficial for the aging process of wine, excessive amounts can lead to oxidation and other wine errors. This is why wine in a keg is regularly "refilled" and refilled upward with wine to minimize headroom. In a bottle, ullage or wine "filling rate" can be an important indicator of the type of treatment and storage conditions stored wine. After-market resellers and wine auction houses will often check the older ullage levels. vintages to determine the potential quality and value of wine.
Video Ullage (wine)
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At the winery, the natural evaporation process creates ullage in the barrel by causing some alcohol particles and water to escape as steam, a loss sometimes referred to as "the share of angels". If the wine is in a container that is not completely airtight, the steam molecules (along with carbon dioxide) will diffuse out of the container through openings in wood and around the bung and replaced with oxygen molecules. While some oxygen is beneficial in the maturation and breakdown of some phenolic compounds such as tannins, excessive amounts of oxygen can interact with Acetobacter present in wine and begin the process of turning wine into vinegar. To prevent this possibility, the oxidation and decay plants will regularly "add" the barrel by replacing the lost liquid with new wine.
The exact method and time to store wine barrels is determined by each winery and can depend on the type of wine or grape variety produced. One barrel can be terminated anywhere from once a week to every half month. The position of the barrel can affect the speed and rate of evaporation and the need to add. If the barrel sits with the above bung hole, aeration and evaporation occur faster. If the barrel is rotated to the side in a bung over position, then the bung remains moist with wine and aeration occurs at a slower pace. Wines replaced during top-ups are usually the same wine taken from other smaller containers (such as carboy) with the barrel filled to the top to the entry point of the dung causing some spills.
Maps Ullage (wine)
In the bottle
The wine bottle ullage rate is sometimes described as "charge level". This explains the space between the wine and the bottom of the cork. During the bottling process, most wineries attempt to have an initial ullage rate between 0.2-0.4 inches (5-10mm). Because the cork is not a sealant that is completely airtight, some wine is lost through the evaporation and diffusion process. When the age of wine in a bottle, the number of ullage will continue to increase unless the wine is opened, closed and closed again. If the wine is stored on its side, in contact with the cork, some grapes will also disappear with absorption to the cork with longer corks having the potential to absorb more grapes (and thus create more ullage) than shorter corks.
Generally the more the number of ullage, the more potential that wine has been exposed to dangerous oxidation levels. This is why auction houses and adult wine retailers pay attention to the ullage rate in determining the resale value of wine. The ullage level can also provide insight into the type of treatment and storage conditions that wine is stored. Grapes that have been stored at an ambient humidity level and temperatures between 50-59 ° F (10-15 ° C) will experience evaporation and diffusion at a slower rate than wine stored in lower conditions and thus will have a level ullage is lower. Ullage levels are generally important for the possibility of almost all wines in good condition. Vintage Port may be slightly less vulnerable to damage because it is enriched, but the only wine that can not be damaged by oxidation is the Madeira wine, which is already oxidized.
There is a standard description used by wine merchants and auction houses for filling levels (wine ullage levels). Description of different charging levels for Bordeaux and Burgundy wines due to different bottle forms from both regions.
Broadband Broadbent ullage Guide
In the late 1980s, Master of Wine and senior consultant Christie Michael Broadbent auctions developed a guide to evaluating mature wine ullage levels. While the focus of its guidance, especially in Bordeaux, is generally accepted and widely used in the wine market as an evaluation tool for all types of wine. The term is used to describe the level of wine in wine bottles. They are usually used to describe old wine bottles offered for sale in wine auctions and by rare wine sellers. Despite the popularity of the guide, Broadbent has been cited as regretting his decision not to copyright it.
References
Source of the article : Wikipedia
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