What is 'vorlauf' in the context of brewing?

Vorlauf refers specifically to the initial process of recirculating the wort during the lautering phase of brewing. This step is essential because it helps to clarify the wort by allowing any particulate matter, such as grain fragments or husks, to settle. As the wort is drained from the mash tun, it is typically cloudy, and the vorlauf process involves returning this cloudy wort back to the mash to filter through the grain bed.

This not only clarifies the wort but also helps to prevent the grain bed from becoming compacted, which could hinder the flow of liquid through it in the lautering stage. Properly executed vorlauf leads to a clearer wort for subsequent boiling and fermentation processes. Thus, recognizing vorlauf as the initial running of cloudy wort illustrates an important aspect of the brewing process that ensures optimal clarity and quality of the beer being produced.