Nothing was wasted in the salting factories: the fish bones were used as animal food or fertilizer, the guts for making fish sauce, and obviously the fish flesh for the saltings.
First the fish was washed with fresh water, then it was prepared for salting its meat (salsamenta) or for making the sauces, for which the fins and head were removed, it was cleaned and descaled. It was cut into slices or even pounded so that the salt would easily penetrate. It was then put in the tanks with layers of salt and covered to complete the process. The left over bones were ground and made into flours for fertilizers or animal food.
The guts were used to make fish sauces, for which they started with obtaining the so-called liquamen, the fundamental basis of the other preparations. For this the guts of certain fish were placed in the basins with shredded fish flesh and small fish, and were all stirred together until they became a homogenous paste, it being frequently beaten to produce fermentation with the salt which prevented purification. The analysis of scales and vertebrae found in our factory has allowed for the identification of the species scomberesox saurus (known commonly as “paparda”), which suggests it was used together with other more characteristic species such as mackeral.
When due to the action of the heat the product was reduced, baskets were submerged to extract the liquid and filter it: the resulting product was garum. The leftover remains, once the garum had been extracted, was the so-called allec, a less refined and therefore cheaper and less good quality product. The muria brine exuded by the fish was another by-product of the process. Other by-products, such as cod and the miscellanea had medicinal or dietary properties. Sometimes a layer of aromatic herbs and spices were put into the preparation process.
After making the garum or salsamenta they were bottled in amphora in storage areas until their subsequent transportation.