In a medium saucepan, combine water, ginger, turmeric and cayenne and bring to a simmer over medium heat. Lower heat, cover and simmer for 15 minutes. Remove from heat and cool slightly, leaving the lid on. Using a fine-mesh strainer, strain into quart-size glass container. Pour into clean saucepan and reheat. Add lemon juice and honey, stirring until it dissolves. Serve warm or cold. Store in the refrigerator for up to three days.