Addresses AP® Chemistry Big Idea 3 and Learning Objective 3.9. Determine the concentration of ascorbic acid in a commercial fruit juice by redox titration. Titrate solutions of known ascorbic acid concentration to create a standard curve, then titrate a sample of fruit juice and determine the concentration of ascorbic acid from the curve. Fruit juice connects redox and titration to the real world and captures students' interest. Materials are sufficient for 30 students working in teams of 3.