Music is increasingly being used in a variety of health and mental health contexts for mood regulation purposes. Music is also a commonly used stimulus in mood induction studies in a variety of fields. However, basic biological mechanisms can be triggered when listening to music, resulting in intense but relatively short-lived affective responses. In assessing the efficacy of musical interventions or mood induction procedures, researchers face the difficulty of determining whether the responses being evaluated are these immediate emotional responses or whether the music has had an enduring effect on participants’ moods. This case study provides an account of a study in which we used psychometric measures and qualitative reports of mood effects in order to pick up different affective responses to music. The case sheds light on the importance of careful experimental design in music intervention or musical mood induction studies. In particular, we highlight the importance of ensuring that mood measures are carefully selected and that they are administered at appropriate time points in order to measure the desired construct.