Andresen produces Port wines from the Douro region of Northern Portugal, drawing on the valley's distinctive terroir and traditional grape varieties. The winery's portfolio centers on fortified expressions: the Royal Choice 20 Years Old Port, a complex blend of Tinta Roriz, Tinta Cão, Touriga Franca, Touriga Nacional, and Tinta Barroca; the Vintage Porto, built from the same five varieties; and the Late Bottled Vintage Porto, a lighter blend of Tinta Roriz, Touriga Franca, and Tinta Amarela. Each wine reflects the Douro's reputation for producing deeply structured, age-worthy fortified wines. Wine Enthusiast, Decanter, and Wine Spectator have rated the house's offerings, with the Royal Choice and Vintage Porto earning particular recognition among prestige critics. The winery's focus remains on Port's classical expressions—styles that demand patience and reward extended cellaring.