Wineries often rent out part of their facilities to others for banquets, parties, meetings, etc. In most cases, if you make a separate charge for the use of a banquet or meeting room, retail sales tax does not apply. Instead, this income is subject to B&O tax under the Service and Other Activities classification. However, banquet/meeting facilities provided by a lodging business (hotel, motel, etc.) are subject to sales tax.
If a single charge is made for both a banquet room and meals/drinks (the banquet facility charge is not separately stated), then the total charge is subject to Retailing B&O tax and you must collect retail sales tax.