Cellardoor Winery of Lincolnville is planning to open a 5,000-square-foot tasting room at Thompson’s Point in Portland next spring. The satellite location will be known as Cellardoor at the Point and will host wine tastings, dinners, cooking classes, food-and-wine pairings and other special events. It also will have retail space for selling the company’s “Cellardoor at Home” product line, which includes jams and jellies, oils, vinegars, desserts, syrups and other food products. The large space “will give us a lot of opportunity to do some of our bigger dinners and get creative on what kind of events we want to plan,” said Bettina Doulton, who has owned the winery since 2007. Thompson’s Point is a 30-acre former industrial site that juts out into the Fore River.