What does the term 'black patent' refer to in brewing?

Black patent refers to a specific type of malt that is used in brewing, primarily known for its influence on the color of beer. This malt is produced through a roasting process that creates a very dark color and distinct roasted flavors. It is used in relatively small amounts to contribute to the color of darker beers such as stouts and porters, imparting rich, deep hues that are characteristic of these styles. The use of black patent malt is crucial because it allows brewers to achieve the desired visual characteristics of a beer without adding significant sweetness or body that additional specialty malts might introduce.

In contrast, the other options do not align with the definition of black patent malt. A type of yeast refers to biologically active organisms used in fermentation processes, and a specific style of beer would denote broader categories and not a specific malt type. A brewing technique refers to methods used during the brewing process for optimal efficiency and does not particularize the characteristics of malt. Thus, the correct answer identifies black patent as a malt that notably affects the color of the beer.