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How is Rosita Ratfish Liver Oil processed from start to finish?

Purchasing Ratfish livers on the open market or from brokers can be problematic regarding the freshness, source, and even fish species the livers are obtained from. By using freshly caught fish and not importing frozen products quality is optimally maintained and the properties of the raw materials will not deteriorate. To ensure total control over sustainability, quality and freshness of ratfish livers the Rosita team employs their own small artisan fishing boats.

The wild Ratfish are sustainably fished from the crystal clear & pristine sapphire blue waters of remote Norway. The fishing grounds are located in secluded areas that are beautiful beyond description. The original fishing/harvesting method used by the fishermen were lines pulled in by hand from boats. No commercial fishing boats are used for harvesting the fish. Instead, open boats are used to harvest the fish. The wild Ratfish are hauled into the boat from the icy cold waters of the Arctic Circle, and shaken off the hook. Rosita’s fishermen use their razor-sharp ceramic blades to cut across the throat and then make a longitudinal incision down the belly of the Ratfish which allows the entrails to spill out. The livers are then pulled out, carefully cleansed from blood, membrane and other impurities by washing in pure cold water. After this the gall-bladder is removed.

The livers are then immediately placed under proprietary conditions to maintain freshness. The entrails are fed to seagulls which also commonly attracts the interest of huge white-tailed fish eagles. The fish and livers are then quickly ferried to shore. Within a very short time of returning to the docks, the fresh livers are carefully hand inspected at Rosita’s zero-emission production premises. Rosita goes to great lengths to make sure the livers are very carefully handled and never exposed to high temperatures, chemicals, or reactive metals. Rough handling of the liver can cause it to bruise, promoting degradation of the liver and lowering the quality of the oil produced. Only the undamaged, fresh livers are suitable for the finest liver oil. In accordance with ancient tradition, only livers of a specific appearance and weight are used. The quality of fish liver oil is highly dependent on the quality of the liver. Crushed and bruised livers are never used! If the Ratfish livers are small and discolored (or have a dark appearance) this indicates a scarcity of food for the Ratfish and the possibility they may not be healthy. The best Ratfish livers are large and beautifully plump, soft to the touch with an almost cream-colored appearance. This indicates the Ratfish have plenty of food and are “thriving”. Such livers abound with fine quality oil that appears perfectly pellucid and pale-colored with a mild fishy taste.

Once the livers are selected the next step involves “releasing” the oil from the fresh Ratfish livers using the exclusive “Rosita Ancient Production Method”.

Ancient Rosita Method: “Releasing” the oil from liver

There exists an ancient method for Ratfish and cod liver oil extraction that is extremely rare in today’s fish oil world. The entire steps of this method remain a secret. This method produces the most precious and rare Ratfish liver oil. The oil is produced under the total absence of heat, a process that protects its nutritional value. The liver and its oil are never subjected to chemical treatment, solvents, mechanical devices, rendering, Peter Möller’s method (steam), distillation, winterization, putrefaction, decomposition, alkali refining, bleaching and deodorization (these are dirty words to Rosita). Every precaution is taken to preserve the therapeutic properties of Ratfish liver oil and its natural abundance of nutrients including fat-soluble vitamins, fatty acids, natural sterols, antioxidants, volatile substances and minor components.


The Ancient Norse people observed that the appearance, size and texture of fish livers vary considerably depending on the seasons. For certain seasons, the livers were beautifully plump, with a light cream color and very soft to the touch, “bursting” with oil of a superior quality. During other seasons the livers were smaller, with a reddish hue, firmer to the touch, with very low oil content. The ancient Norse people also knew both air and water temperature vary from season to season and believed the water temperature influenced the physical characteristics of the liver. As such, they discovered those plump, cream colored oily livers could revert back to their smaller, reddish form by “releasing” the oil they contain. The trigger for releasing their oil was a change in temperature which mimicked specific seasonal changes in water temperature. This was achieved by transferring freshly removed cream colored fish livers to warmer dwellings which had to be at a slightly greater temperature than the cold ocean temperature the livers were previously exposed to. The livers would then naturally and gradually release the raw pale golden oil contained in their cells without any intervention whatsoever! As the oil is released, the livers shrink and revert back to their smaller, reddish appearance. This gave rise to the basic oil extraction principle that the ancients went about perfecting and that Rosita uses today. Nature does all the work, not decay, not decomposition, and definitely not heat, steam, chemicals, solvents or any form of refining.


Many companies use heat to maximize the quantity of oil extracted from the livers but at the high cost of accelerated oxidation and damage to heat-sensitive nutrients. Such procedures may result in quantitative improvements but not qualitative. No mechanical devices are ever used during the extraction process, only the beautiful ancient principles given to us by nature herself.


Rosita adds a modern twist by carrying out the production process under oxygen–free conditions and low light conditions. The liver and its oil never come into contact with reactive metals, plastics etc. The livers are also never frozen at any stage of production – the coldest temperature that the livers are subjected to mimics the lowest temperature that the wild Ratfish liver is exposed to in the ocean during a specific season.

Immediately after extraction, the oil is very lightly filtered, with the help of gravity only, at low temperatures. This simply removes particles of liver tissue, without refining the oil in any way. In contrast, conventional procedures remove many of the healthy fat soluble compounds, and therefore affect the nutritional quality of the oil.
Tiny amounts of the plant Rosemary and full spectrum natural (GMO-free) vitamin E (not isolated vitamin E) are added to maintain the freshness. The oil is then bottled in amber glass to extend its shelf life and freshness by protecting it against light deterioration. The bottling takes place at very low temperatures and in the absence of oxygen. The end result is 100% unadulterated Wild & Raw Ratfish Liver Oil, which contains no synthetic nutrients. We believe it is the most authentic product available.
Samples of this oil are also sent for analyses to one of the European Institutes that Rosita is affiliated with. The bottles are then carefully packed and shipped to points around the globe.

Rosita handcrafted Ratfish liver oil is produced without polluting the environment, including the air and water. Each batch of Rosita handcrafted Ratfish liver oil can actually be traced back to the fishing grounds where the fish were harvested!


This article applies to: Rosita Ratfish Liver Oil

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