Cowl (oast)

A cowl (oast) refers to a rotating vent placed on the roof of an oast house. An oast house is a building designed for kilning hops as part of the beer-making process. The cowl's primary function is to regulate airflow through the kiln during the drying process.

The design of a cowl typically involves a vane or other mechanism that allows it to orient itself according to the prevailing wind direction. This ensures that the airflow through the oast house is optimized for efficient and even drying of the hops. The movement of the cowl helps to draw out moisture-laden air from within the kiln and replace it with drier air from the outside.

Different types of cowls exist, varying in size, shape, and construction materials. The specific design of the cowl can influence the rate of airflow and the overall efficiency of the drying process. Traditional cowls were often made of wood, while more modern versions might utilize metal.

The cowl is a crucial component of the oast house, playing a vital role in the quality of the dried hops and, ultimately, the flavor of the beer produced. The presence and functionality of the cowl are often considered key features when identifying and preserving historic oast houses.