* The hay: Hay contains a variety of microbes, including bacteria, fungi, and protozoa, that live on and within the plant material.
* The peppercorns: Peppercorns also harbor microbes, though typically fewer than hay.
* The water: The water used to create the infusion can contain microbes from the source, such as tap water or rainwater.
* The air: Microscopic organisms are present in the air and can easily contaminate the infusion.
These organisms are introduced into the infusion during the preparation process and then multiply rapidly in the nutrient-rich environment.
The process of observing these organisms in infusions was instrumental in the development of microbiology. Early scientists like Antonie van Leeuwenhoek observed these "animalcules" through his microscopes and made important discoveries about the nature of microbes.
