What is liver?
In the succulent and variegated world of offal, liver is the unquestioned protagonist. It owes this popularity to its particular composition. Anatomically speaking, liver is a gland, which serves multiple functions, the main ones being the storage of glycogen, protein synthesis and the production of bile.
What does liver taste like?
Its anatomical role belies its typical flavour, a delicate mix of sweet, bitter and acidic tastes which lend themselves to being enhanced in an endless number of recipes. Strictly speaking, it is possible to consume the liver of all those animals which normally provide us with nourishment, fish included, but the ones we are most familiar with come from pigs and calves since they are cheap, widely available and easy to cook.
The chemical composition of liver
While differing from one species to another, the consistency of liver is always quite similar, this being something a skilled cook has to bear in mind. In particular, it is rich in glutathione and thiols. The former is a tripeptide made up of the amino acids cysteine, glycine and glutamate (which is the salt of glutamic acid) and is partly responsible for the “metallic” taste of liver. The latter are alcohols to which we owe the characteristic smell of this gland. During the cooking process, the two compounds have no small impact on the taste and aroma of this dish. To mitigate this somewhat aggressive flavour, it is a good idea to leave raw liver to marinate in an acidic substance, such as lemon or lime juice, or even vinegar. This will actually limit the oxidation of glutathione and thiols during the subsequent cooking process.