To make it easy to remove delicate fish from the slow cooker after poaching, we often use a foil sling. To form a sling, fold a sheet of aluminum foil into a 12 by 9‐inch rectangle and press it widthwise into the slow cooker. Before serving, use the ends of the sling as handles to lift the fish out of the slow cooker fully intact.

Poaching is a naturally low‐calorie, low‐fat method for cooking fish, but it typically requires prepping a slew of ingredients for the poaching broth, only to dump out at the end of cooking, plus much of the fish’s flavor leaches out into the liquid. Fortunately, in the slow cooker these problems can be easily solved using a shallow poaching technique: We simply rest the fish on top of a few citrus slices to keep it elevated for even cooking, and we use just enough liquid to gently steam, not simmer, the fish. Also, during our testing, we learned that adding wine to the poaching liquid helped to achieve perfectly cooked fish quickly at a lower temperature. This is because wine lowers water’s boiling point and produces more vapor to cook the fillets.

Ensuring moist fish in the slow cooker starts at the fish counter where we grab 1 to 1½‐inch‐thick fillets and steaks, which can cook for a longer period of time without drying out. It is also important to choose fillets or steaks that are similar in size and thickness so that each piece will cook at the same rate. To further guarantee that the fish is properly cooked, we use the low setting and 1‐hour time ranges to reduce the opportunity for overcooking. Start monitoring the fish’s temperature at the low end of the range until you have experience cooking it in your slow cooker.

Yes, you can cook shrimp and scallops in a slow cooker, but the key is to add them toward the end of the cooking time and let the moist heat of the slow cooker gently cook them through. For instance, we learned it takes just 20 minutes to cook shrimp in a slow cooker, so for a seafood stew or soup, we let the base of broth, vegetables, and aromatics simmer for several hours to soften the vegetables and meld flavors before we add the shrimp. For our slow‐cooker shrimp boil, most of the ingredients cook all day, but again, the shrimp is stirred in last. Scallops take a little longer than shrimp to cook through in a slow cooker, but the same principle holds true; use the majority of the time to slow cook most of the ingredients, then add the scallops for the last 30 minutes or so.

After much testing with clams and mussels, we learned that by the time they become hot enough for the shells to open up (and sometimes they don’t open up), their tender meat is tough and inedible. In short, the slow cooker doesn’t get hot enough fast enough to be able to safely cook clams or mussels.