Students need procedural understanding—that is, knowledge of the procedures that scientists use to establish scientific evidence (also known as “concepts of evidence”), to successfully perform scientific investigations, and to evaluate public and scientific claims. However, concepts of evidence are seldom explicitly targeted in routine practical activities in secondary school science classrooms. We describe how a commonly used practical activity, yeast fermentation, can be modified to provide a meaningful context for developing students' understanding of concepts of evidence associated with measurement, as well as more difficult-to-learn scientific ideas, such as rates of reaction. The modified practical activities give students opportunities to exercise their creativity in assembling setups; brainstorm solutions to design problems in teams; reflect on their decisions related to concepts of evidence associated with measurement when designing their setups; compare the validity and reliability of data produced using different setups; and develop their understanding of difficult-to-learn scientific ideas.