Acids in wine ripened grapes. While concentration varies among grape varieties, it is usually found in higher levels with red wine grapes. The acid is created as a byproduct of the metabolization of nitrogen by yeast cells during fermentation. The combination of succinic acid with one molecule of ethanol will create the ester mono-ethyl succinate responsible for a mild, fruit aroma in wines. Acidity is highest in wine grapes just before the start of "veraison", which ushers in the ripening period of the annual cycle of grape vines. As the grapes ripen, their sugar levels increase and their acidity levels decrease. Through the
The purpose of a system is what it does or sheer ignorance of circumstances." The term is widely used by systems theorists. It is generally invoked to counter the notion that the purpose of a system can be read from the intentions of those who design, operate, or promote it. From a cybernetic perspective complex systems are not controllable by simple notions of management, and interventions in a system can best be understood by looking at how they affect observed system behavior. When "side effects" or "unintended consequences" reveal that system behavior is poorly understood, then taking the POSIWID perspective allows the more political understandings of system behavior to