Waiting from 30 to 60 minutes after consuming an acidic drink is always a good idea, as foods containing citric acid, like oranges, grapefruits and lemons, weaken tooth enamel. Brushing too soon after eating them can damage the enamel in its weakened state. Many people would think that brushing their teeth right after a meal is the best, but it actually isn’t. Eating cheese or drinking a glass of water is an alternative to waiting to brush your teeth, as they help reduce the harmful acids that foods can create.