To make 1ltr of colatura Luigi Crescenzi guts and removes the heads from 20kgs of anchovies, layers them with sea salt in oak barrels and leaves them, weighted, for between 6-24 months and then harvests the essence through a small hole in the bottom of the barrel.
The origins of colatura lie in the ancient roman sauce of fermented fish garum. Garum, similar to many Asian fish sauces made today, relied on enzymes in the guts which go to work on the fish flesh breaking down proteins into their constituent, flavour-filled amino acids and fats into fatty acids. These proteolytic enzymes are present in the flesh too but there are more of them in the intestines. In Roman times garum made from fish that were gutted and had their heads removed (like colatura) was called muria and was slightly less pungent but very highly prized.
Luigi Crescenzi's tiny production uses anchovies caught sustainably off the coast of Anzio and you only need a sprinkling of it to bring a rich, savoury dimension to any food. Try it on tomatoes, wilted greens, grilled meats or pasta; the challenge is not to become too addicted