A biological sterilization indicator (BI). The BI can include a housing, and a container positioned in the housing. The container can contain a liquid and at least a portion of the container can be frangible. The BI can further include a first chamber and a second chamber. The second chamber can include at least one source of biological activity. The BI can further include a substrate positioned in the housing between the first chamber and the second chamber. The substrate can be positioned in fluid communication with the first chamber and the second chamber, and the substrate can be further positioned such that the substrate is not in direct contact with the source of biological activity.