In this lesson we are going to tackle sous vide fish. Fish is one of the hardest items to recommend times and temperatures for due to the wide variety of preferences people have, ranging from sushi (or sushi-like) to flaky and fully cooked.
Fish are also a lot more sensitive than many items you sous vide and sometimes small temperature variations can result in large swings in texture. There is also such a wide variety of fish that it is hard to make blanket statements that will apply to all of them.
I'll try to give you my preferences for fish and explain what other people like and why they like it. Hopefully then you will have the information you need to successfully cook sous vide fish to your own tastes.
My best-selling Modernist Cooking Made Easy: Sous Vide also explores these items in much more detail.
Unless you are heating your fish above 130°F (54.4°C) for an extended time, be sure to only use fish that you would feel safe eating raw and you are not serving it to immunodeficient people. This is true not only of sous vided fish, but also of fish cooked in a traditional manner.
There are a few things you can do to fish to make it more appealing when cooking with sous vide.
The top suggestion is to brine your fish before you cook it. The brine will help firm up the fish, especially when it is cooked at low temperatures, and will also pull out the albumin, resulting in a cleaner finished dish.
The brine can either take the form of a wet brine or a dry brine.
A wet brine is usually a 5% salt to water ratio, and is applied for 5 to 15 minutes, depending on the fish. Make sure the brine is cool when the fish is added.
A 5% brine can be made by combining about 4 cups of water with 1/4 cup kosher salt, heating it until the salt dissolves, then chilling it. Some brines also have sugar or spices added.
A dry brine is easy to use, just salt the fish and refrigerate it for at least 30 minutes before cooking it. Dry brines typically result in a less watered down flavor and are faster to apply since you do not have to heat and cool water.
I recommend portioning out the fish before you sous vide it as well. Most fish becomes very delicate once it comes out of the sous vide bath and can tend to fall apart. Cutting it into portions first makes it much easier to handle.
If you are cooking more than one piece of fish in the same bag, it is usually best to add some olive oil or butter as well. This will help prevent the pieces from sticking together.
The flesh of fish is generally soft so be careful when vacuum sealing it. A strong vacuum can crush the flesh of the fish and change the texture. I often just use Ziploc bags when cooking fish because there is no added pressure to the fish itself.
There is a wide range of doneness you can shoot for when cooking fish sous vide.
The lowest temperature most people use is 104°F (40°C). This just slightly heats the fish through, releasing some flavor but doesn't really change the texture. There are similar results at temperatures up to about 110°F (43.3°C). This fish is almost sushi-like.
From 110°F (43.3°C) to 120°F (48.9°C) the fish generally begins to have more pronounced texture changes, becoming slightly more flaky and firm, while still retaining a lot of moisture.
Above 120°F (48.9°C) the fish starts to become more and more flaky and starts to dry out. The top temperature I usually cook any fish at is 132°F (55.5°C), though some people like it up to 140°F (60°C).
Warning: Only temperatures above 130°F (54.4°C) will pasteurize the fish, and only when held for several hours, something that is usually not done with fish. I highly recommend only using fish you would feel comfortable eating raw, and not serving it to any immunodeficient people.
Different types of fish are best at different temperatures, so it's usually best to look at a recipe for a specific fish, or a similar type of fish, when you are trying to determine what temperature is right for the preparation you are after.
Almost all fish only needs to be heated through and not tenderized.
The length of time needed to heat it through depends on the thickness:
While those times generally work, many people don't cook their fish more than an hour because it can start to degrade in the waterbath. Using a shorter time on a thicker piece of fish means the middle will be cooler, but this generally isn't a bad thing.
You can follow the charts on the Sous Vide Fish Cooking Times page for the specific amount of time based on the thickness of your fish.
Depending on your preparation, you can decide to sear the fish or skip the searing step. For lower temperature cooks, the sear is often not needed. This is also true for "poached" preparations where you want to keep the flavor and texture delicate.
For some preparations, you will want to dry off the fish really well then quickly sear it. Fish can overcook quickly, so you shouldn't go more than 30 to 60 seconds per side.
I will also often just sear one side of the fish, resulting in a better crust and presentation, without risking over cooking it as much. This also helps prevent the fish from falling apart when you try to flip it multiple times.
Most fish is eaten right after you cook it, but some fish is best chilled afterwards. This is usually best done by leaving it in the sous vide pouch and dunking it in ice water. It can then be refrigerated until it is time to serve it. This will help the fish stay safe to eat and help prevent it from breaking apart.
Have you had some great experiences with sous vide fish that you'd like to share? Have any follow up questions you need answered? Let me know in the comments or on the Exploring Sous Vide Facebook group.
In this lesson we discussed how to sous vide fish.
Do you know anyone that is struggling with sous vide and would find this information helpful? Why not do them a favor and send them a link to this Exploring Sous Vide email course or get them a printed version of this course!
Thanks again and happy cooking!
Jason Logsdon, Amazing Food Made Easy