A wine steward is a person who is responsible for managing a wine collection and providing guidance on wine selection and service. Other names for a wine steward include sommelier, wine expert, wine director, and cellar master. A sommelier is a certified wine professional who has in-depth knowledge of wines and can recommend the perfect pairing for a particular dish. A wine expert is someone who has extensive knowledge of wine production, wine regions, and grape varieties. A wine director is responsible for managing the entire wine program in a restaurant or hotel. A cellar master manages the wine cellar and is responsible for ensuring the wines are stored at the appropriate temperature and humidity to maintain their quality.