Asda has remained tight-lipped about the reasons for Stewart's departure, and confirmed that it is looking to recruit.
Stewart's appointment in May 2007, from the retailer's electronics department, combined the roles of two separate category directors
- one for wine and one for beers and spirits
- and signalled Asda's commitment to driving the development of its drinks strategy.
When Stewart took the reins the wine team had already started working on a full-scale revision of Asda's range, which was slimmed down to 580 lines last September.
Stewart was also responsible for creating a new category team to focus on several areas, including promotions and events, pricing strategy and corporate social responsibility.
In May this year two new product development managers - Becca Reeves from Thierry's and internal recruit Katie Mollet - were appointed to join chief wine buyer Philippa Carr MW.
CJ Antal-Smith is leading beers and spirits as buying manager, with new recruit Drew Tiffin as spirits buyer.
Asda sits in third position in the wine market, growing its market share to 11.7%, according to the latest data from TNS.
Tesco and Sainsbury's continue to retain their number one and two spots, with market shares of 30.1% and 18.7% respectively, though both figures have fallen slightly in the 12 weeks to June 15.