To test for the presence of reducing sugars, a food sample is dissolved in boiling water. Next, a small amount of Benedict's reagent is added and the solution begins to cool. During the next four to 10 minutes, the solution should begin to change colors. If the color changes to blue, then no glucose is present. If a high amount of glucose is present, then the color change will progress to green, yellow, orange, red and then a dark red or brown.