VA cases highlight importance of good ullage management

摘要

OXYGEN exposure and poor ullage management are the two main causes associated with recent cases of volatile acidity (VA) issues, confirmed by the Australian Wine and Research Institute's (AWRI) helpdesk.AWRI oenologist, Matt Holdstock said VA is a sign of spoilage and is quite easily measured as acetic acid."It can arise from a number of different causes, and these include wines sitting on ullage or exposed to oxygen for periods of time allowing spoilage organisms, such as acetic acid bacteria, to produce significant quantities of acetic acid under aerobic(oxygen-rich) environments," he said."Other bacteria including lactic acid bacteria can also produce significant quantities of acetic acid in the presence of sugar, as can yeast, in particular Brettanomyces yeast, when grown under aerobic conditions."