Emotional contagion is a mechanism by which affect experienced by one person in a group is transmitted to others in the same group. When this happens, the group dynamic is influenced. This paper provides a method to analyze an Open Software project to determine the connection between emotional contagion and software production in such an environment, if any. The project change management database is mined to extract change comments in chronological order and by user id. Sentiment analysis is employed to determine affect in the change originating from each userid. File changes are tracked to link them together in the same areas, using a temporal and file locality principle. The correlation between affect and area is then used to prove or disprove whether or not emotional contagion influences open software production. Although in this paper the proposed method is applied to only one project, the method is general and can be reused for experimental validation.