Gutting sardines is mostly a matter of personal preference. While scaling them is a mandatory operation, the innards' bitter taste is prized in some cultures and is said to add a certain complexity to the fish. Along with personal preference, how you plan on cooking sardines plays a role in the preparation, as does the freshness of the sardines.
Leaving Them Whole
Grilling and frying recipes are the most likely to call for leaving sardines intact without gutting them or removing their heads. Using these preparations, the innards of the fish are hard-cooked and offer a complex, bitter flavor to the oily fish. The benefit of this type of preparation is that there is little work involved as the entire fish can be left whole. Select fresh sardines when preparing them in this way and use them within one to two days of purchase. Remove the scales, give the sardines a good rinse, and pat them dry before using in your recipe.
Whole Fish Safety Concerns
Sardines are at the bottom of the food chain and feed entirely on plankton. For this reason, they are much safer for eating, even with their guts, than many larger species of fish that build up heavy metals and contaminants in their tissue throughout their lifetime. Additionally, sardines are high in omega-3 fatty acids, vitamin B12, and vitamin D, making them an appealing choice for heart health, bone health and an overall balanced diet.
Keeping Them Fresh
Sardines are a highly perishable food and this is the leading reason that they are so frequently found canned. When buying fresh sardines, look for those that have shiny skin, bright eyes and a fresh smell. Normal refrigerator temperatures of 36 to 40 degrees Fahrenheit are prime for spoilage in sardines. Store fresh sardines in a zippered plastic bag submerged in a bowl of ice in your refrigerator for up to two days before cooking.
Getting the Guts Out
Gutting sardines is a simple process, so don't let lack of experience prevent you from learning. For a filleted sardine recipe or if your preference is simply to gut them, remove the scales by running the blade of your knife against the grain of the scales and back again. Use kitchen scissors to remove the fins and to cut from the tail to the head along the fish's belly. Rinse the inner cavity of the sardine under running water as you work your finger in it from the tail to the head, removing any guts as you go. Rinse each fish's inside once it is gutted.