Root cellars are for keeping food supplies at controlled temperatures and steady humidity. Many crops keep longest just above freezing (1–3 °C) and at high humidity (90–95%), but the optimal temperature and humidity ranges vary by crop, and various crops keep well at temperatures further above near-freezing but below room temperature. A few crops keep better in low humidity. Root cellars keep food from freezing during the winter and keep food cool during the summer to prevent spoilage. Typically, a variety of vegetables are placed in the root cellar in the autumn after harvesting. A secondary use for the root cellar is as a place to store wine, beer, or other homemade alcoholic beverages.