Malt liquor is distinct from traditional beer because it uses little to no hops, leading to a much sweeter, less bitter taste. Instead of relying on hops for balance, brewers add fermentable adjuncts like corn or rice to boost the alcohol by volume (ABV) at a lower cost.While beer relies heavily on hops for flavor, aroma, and bittering, malt liquor production keeps hops to an absolute minimum. This choice produces a few distinct characteristics:Lower Bitterness: With fewer hops, malt liquor typically scores between 12 and 23 on the International Bitterness Units (IBU) scale, practically eliminating hoppy notes.Sweeter Profile: The lack of hop bitterness highlights the sweet, grain-like flavors of the malted barley and added adjuncts.Higher Alcohol: Without hop compounds restricting yeast growth, brewers can push ABV levels between 6.5% and 8.5% (or higher) in products like Colt 45 or Steel Reserve.

(http://www.autoadmit.com/thread.php?thread_id=5883258&forum_id=2#50004589)

Hops are used for flavor and are not fermented into alcohol. Since malt liquor is for alcoholics that want the most ABV per $ spent they don't use a lot of hops. But they still use some to give that swill some beer-like flavor.

(http://www.autoadmit.com/thread.php?thread_id=5883258&forum_id=2#50004631)

but since people were buying the jugs, and since bottles of 'train weren't as popular as before, they just cut out the extra step.

(http://www.autoadmit.com/thread.php?thread_id=5883258&forum_id=2#50004688)