ABSTRACT
The modern versions of gravlax are quite mild compared with the original ones, very mildly fermented. In a typical gravlax, the fish loses water and approximately 4% of its weight. Salt also affects the fish structure. In practice, all types of raw materials have been, or are being, fermented: fruits, vegetables, cereals, meat, and fish. In many cases, fermentation was the preferred preservation method for fatty fish because salting and subsequent air-drying fatty fish would easily result in a rancid product. The anaerobic conditions necessary for fermentation prevent the easily perishable fish fat from turning rancid since this is a reaction between fatty acids and oxygen from the air. Home -producers of rak-fisk, for example, are warned to adhere to high hygiene standards, ensuring that the fish is at no point in contact with soil.
