Sous Vide Flank Steak Recipe, Temp & Time

Flank steak is relatively low in price tag, but it’s actually packed with a rich, beefy flavor. I especially love cooking this tough, lean cut sous vide, which breaks down the proteins and makes the meat incredibly tender. After that, a quick sear at high heat caramelizes the exterior, resulting in a beautiful chunk of roast that’s tender and juicy on the inside, crispy on the outside, and flavorful throughout. This simple and easy-to-follow sous vide flank steak recipe is sure to impress your guests, so give it a shot! 

Ingredients:

• 1.5 lbs flank steak
• 4 tablespoons olive oil, divided
• Kosher salt and black pepper to taste
• 3 cloves garlic, minced
• 2 tablespoons soy sauce
• 1 teaspoon smoked paprika
• 1/2 tablespoon finely chopped fresh oregano
• 1 teaspoon dried rosemary
• 1 teaspoon dried thyme

Equipment:

• INKBIRD Sous Vide Cooker
• Vacuum Sealer
• Vacuum Seal Bag
• Fork
• Sous Vide Container
• Saucepan
• Cast-Iron Skillet

Should You Marinate Flank Steak?

Although many recipes say that sous vide doesn’t require marinating because the cooking process itself is long, allowing seasonings to penetrate the meat, my experience suggests otherwise. I’ve found that the flank steak always tastes better when marinated beforehand. However, if you’re short on time, cooking it directly is perfectly fine.

If you decide to marinate like I do, first you need to use a fork to poke some holes in both sides of the steak, which allows the seasonings to penetrate better. Avoid scoring it, as juices will run out during searing.

Then, combine olive oil, salt, black pepper, minced garlic, soy sauce, smoked paprika, fresh oregano, dried rosemary, and dried thyme, and coat the flank steak with this mixture. If you want the meat to be more tender, add a teaspoon or two of vinegar. Let it marinate uncovered in the refrigerator for about 2 hours.

Sous Vide Flank Steak Time and Temp Chart

Sous vide is all about temperature and time, which determine the doneness and the texture of the flank steak. My preferred temperature is 129°F (54°C), with a cooking time of 2-4 hours. However, you can choose from the chart below according to your preferences.

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How to Sous Vide Flank Steak?

Now that you have the sous vide flank steak temperature and time, it’s time to get started! The steps are similar to cooking any other food sous vide. Here’s how:

Step 1: Marinate the Steak. Marinate your steak using the ingredients and steps mentioned above.

Step 2: Preheat and Bag. Fill your container with water to about two-thirds full, then plug in your sous vide cooker. Set the temperature to 129°F (54°C) and the time to 2.5 hours, or adjust according to your preferred settings from the chart above. At the same time, take the marinated steak out of the refrigerator and place it in a vacuum bag. If there is any leftover marinade, pour it into the bag as well. Seal the bag using a vacuum sealer or the water displacement method.

Step 3: Sous Vide Flank Steak. Submerge the sealed bag with the flank steak into the preheated water bath. Let it cook for 2.5 hours, or anywhere from 2-4 hours.

Step 4: Make the Sauce. After the sous vide cooking it up, take the bag out of the water bath and remove the steak, then pat it completely dry with paper towels. Set the steak aside to cool a bit. In the meantime, pour the reserved sauce into a saucepan and bring it to a boil over medium-low heat until it thickens.

Step 5: Sear and Slice. Preheat your cast-iron skillet over medium-high heat for 3-5 minutes until it’s really hot, then add 2 tablespoons of olive oil. Once the oil starts to smoke, gently place the flank steak into the pan. Sear until golden brown, about 60-90 seconds per side. The sous vide flank steak doesn’t need to rest. Just transfer it to a clean cutting board, slice it thinly against the grain, and serve with the sauce immediately.

You may also like: Sous Vide Ribeye Steak, Sous Vide Filet Mignon, and Sous Vide Tri-Tip

What to Serve with Sous Vide Flank Steak?

To be honest, this sous vide flank steak is already a treat on its own, but if you’d like more pairing ideas or recipe variations, I’ve got a few suggestions for you for further reference.

• Sous Vide Potatoes: This is my favorite side dish because it can be cooked alongside the flank steak. And you can make it into creamy mashed potatoes or pan-seared into crispy potato chunks afterwards.
• Tacos: Place thinly sliced flank steak into warm corn tortillas, then top with salsa, guacamole, onions, cilantro, and a squeeze of lime juice.
• Fajitas: Further slice the steak into strips and stir-fry it with bell peppers and onions for a delicious Mexican feast.
• Sandwiches: The leftover slices can be used in sandwiches the next day with other toppings you like, such as onion relish, pickles, tomatoes, and lettuce.

FAQs

Why sous vide flank steak?

With sous vide, flank steak has a narrow window between perfect and overcooked. The sous vide cooker guarantees your entire steak reaches the exact internal temperature you want evenly. It also tenderizes the meat gently over time, yielding a juicier and more tender steak compared to traditional high-heat methods.

Can I sous vide frozen flank steak?

Absolutely. Simply add an additional 0.5-1 hour to the original cooking time to ensure it thaws completely.  

Is it safe to cook at temperatures below 145°F (63°C)?

Yes, it is totally safe to sous vide flank steak at 129°F (54°C), though the USDA recommends that beef should be cooked to 145°F (63°C). The key difference with sous vide is that the extended cooking time effectively pasteurizes the meat and kills all harmful bacteria.