Which beer style is known for having an IBU range of 20-45?

Kellerbier, particularly the amber variation, is indeed characterized by an International Bitterness Unit (IBU) range of 20-45. This range indicates a moderate level of bitterness, which aligns with the style's balanced flavor profile. Kellerbier is a type of unfiltered lager that is typically more hop-forward than other German lagers, although still well-balanced with malt flavors. The moderate bitterness helps to enhance the beer's refreshing qualities without overpowering the malt sweetness that is also present.

The other styles listed typically fall outside of this specific IBU range. Rauchbier, while often well-balanced, generally exhibits an IBU on the lower end due to its smoky flavors taking precedence. Doppelbock tends to have a low IBU, often under 25, focusing on rich malt sweetness instead. Schwarzbier, a dark lager, also usually features lower bitterness, with IBUs falling largely in the range of 20-30, as dark malts can contribute to perceived bitterness without necessarily increasing measured IBU levels.