Which type of malts are characterized by low fermentability?

Caramel or roasted malts exhibit low fermentability because they are typically characterized by a high level of unfermented sugars due to the methods used in their production. These malts are processed through techniques that caramelize the sugars, resulting in flavors and colors that enhance the beer's complexity. The manufacturing process often involves higher kilning temperatures or longer kilning times, which leads to the development of these sugars that do not fully ferment during the brewing process. As a result, they contribute to the body, mouthfeel, and sweetness of the final beer while also influencing its color and aroma.

In contrast, pale malts and base malts, such as those made from two-row barley, are designed for higher fermentability and provide essential fermentable sugars for yeast to convert into alcohol. Crystal malts, while contributing some residual sweetness, still have higher fermentability compared to caramel or roasted malts. Roasted malts, used primarily for coloring and flavor, also have some fermentable components but, like caramel malts, are less fermentable compared to base malts.