Here’s my husband’s advice for beautifully cooked sous vide salmon.
He says, “I suggest using frozen fish, both for convenience and because deep freezing kills the parasites common in wild fish. Fresh-farmed salmon is also good but needs to be consumed within three hours of leaving a refrigerator. For fresh-farmed salmon, 140 F is the minimum temperature needed to kill food-borne bacteria and parasites. If your fish was deep frozen, you can safely cook at a much lower temperature and achieve better taste and texture. In our house, we prefer 120 F.”
For 1.5 pounds of salmon, cut the fish into 4 portions.
Generously salt and pepper the fish, and place fillets in a zip-top freezer bag (you’ll probably need two bags; the pieces should not overlap).
Add herbs to the bags. Fresh is better but dried herbs work, too. Sajid suggests 2-3 sprigs of fresh thyme, oregano, dill, or rosemary (if using dried versions, lightly coat the fish during the salt/pepper step). Add 1 tablespoon of olive oil per piece of fish to each bag.
Fill a large pot or container with water. Secure the sous vide to the side of the container. Remove all the air from the bag using the water displacement method: hold the bag (except the zipper) under water. Zip in a way that forces all air out, without letting water in.
Set the immersion circulator to the desired temperature. Place sealed bags in the water bath. Cook for 45 minutes (if the fish is thicker than 2 inches, cook for 60 minutes), then remove fish from the bags and either sear skin side down in a pan or serve right away.
Note that these cook times apply whether the salmon is fresh or frozen. Either way you’ll end up with a beautifully cooked piece of fish that is pasteurized and safe for immunocompromised diners.