“Beer, if drunk in moderation, softens the temper, cheers the spirit and promotes health.” Thomas Jefferson
Two actions cause color and some flavor: a.Coupling amino acides and, b.Decomposing sugars. All are tied to the Millard reaction of browning & malting grain. Think about your morning toast.
Crisp, Hoppy, Malty, Roast, Smoke, Fruit/Spice, and Tart/Funky. Basically, it is the ingredients in total that influences Taste and Aroma. Without Hops and Yeast you really don't have much of either.
You ever "almost" like smelling the beer more than drinking it-OK never. Nonetheless, those great aromas come from hops and various types of yeast. We do mean literally hundreds of options for yeasts.
Beer when done right plays to all the senses. Clarity does have an appeal for sure. High protein grains like wheat can make for cloudy beers. So the style dictates clarity along with yeast. Think about stouts and Hefeweizens.
To many people, any alcohol consumption has a component of mouthfeel and it is important as it is a tactile feel coming from a drink or food. Protein and viscosity in beer adds to mouthfeel. Yeast and hops must not be forgotten either.
A 5th taste is referred to in the food industry as "umami"; it is somewhat a mystery. But beer lovers are constantly searching for the umami in beer. "Champagne yeast can take an otherwise unremarkable brew and add 'some umami' that brings it all together,” says Quinn Fuechsl