The shiitake is one of the perfect mushrooms, filled with plenty of umami, it is a savory taste that lingers on and on. All kinds of mushrooms contain the glutamates that produce savory flavors of umami, but shiitake and porcini mushrooms have especially high levels of amino acids and glutamates, enhancing compounds called nucleotides. These two umami compounds have a synergic effect on each other creating much more umami flavor than either one could alone.