Tuna ceviche is a fish dish prepared by marinating thin pieces of fresh tuna in citrus juice and other flavorings. Although the fish does not actually cook in a tuna ceviche, the acid from the citrus juice changes the properties of the proteins to give the tuna the texture and appearance of having been cooking by heat. Using fresh, high quality fish and maintaining a clean cooking environment are essential when preparing a tuna ceviche, since the resulting dish will technically be served raw.
Several different kinds of fish can be used in ceviche recipes, but for tuna ceviche it is wise to use the best quality tuna available — which is generally called “sushi grade” or “sashimi grade.” These terms mean that the fish is fresh enough and good enough quality to be eaten raw such as in sushi or sashimi preparations. Tuna for ceviche should be purchased in firm, pinkish-red steaks that can later be diced or sliced before marinating. The fish needs to be broken down into small pieces to increase the surface area and create more opportunity for the marinade to penetrate the fish; small cubes or thin strips or slices are popular choices. The tuna should be marinated in a glass or ceramic container because the acidic marinade might react with metal containers.
The key element to tuna ceviche is the acidic citrus juice that marinates the fish. Although lemons and limes are the traditional choices for ceviche, less traditional fruits such as grapefruit or orange juice can be added at the chef’s discretion. Additional flavors are added to the citrus juice to further enhance the flavor of the tuna. Traditionally, these ingredients include hot peppers and garlic. Since tuna is often associated with Asian cuisine, a tuna ceviche might include less-traditional flavors, such as soy sauce and ginger, that enhance the flavor of this specific fish.
Once the fish is prepared and the marinade is mixed, the marinade is poured over the raw fish and allowed to sit anywhere from a few minutes to a few hours depending on the desired result. Ideally, the tuna becomes firm and opaque on the outer edges and the center remains pink and raw. People who prefer a more opaque fish can let the mixture marinate longer, but should be careful not to let the fish become tough or overpowered by marinating too extensively. The finished tuna ceviche can be served alone, atop chips or crackers, with other proteins, or in salads.