Black in color, American-style imperial stouts typically have a high alcohol content. Generally characterized as very robust. The extremely rich malty flavor and aroma are balanced with assertive hopping and fruity-ester characteristics. Bitterness should be moderately high to very high and balanced with full sweet malt character. Roasted malt astringency and bitterness can be moderately perceived but should not overwhelm the overall character. Hop aroma is usually moderately-high to overwhelmingly hop-floral, -citrus or -herbal. Diacetyl (butterscotch) levels should be absent.