Which Belgian beer style is most likely to exhibit assertively sour, acidic flavors?

Kriek is a Belgian beer style that is known for its distinctive sour and fruity profile. It is a lambic beer that is made by fermenting a base beer with whole cherries, which imparts a significant amount of tartness and acidity. The fermentation process involves wild yeast and bacteria, particularly Brettanomyces and Lactobacillus, which contribute sour flavors and complexity. This style often showcases a balance between the sweet cherry character and pronounced sourness, making it distinctly different from other traditional Belgian styles.

In contrast, while Belgian Dubbel, Tripel, and Quadrupel can have fruity and malty characteristics, they do not exhibit the same level of assertive sourness. These styles typically feature rich malt flavors, with Dubbel and Quadrupel leaning towards darker, caramelized notes, and Tripel focusing on a dryer, spicier profile. Therefore, when considering the defining characteristics of sourness in Belgian beers, Kriek stands out as the most likely candidate to present assertively sour, acidic flavors.