Sous Vide Green Beans

January 7, 2012

Sous Vide Green Beans

Sous vide green beans are trimmed beans sealed in a bag with butter and salt, cooked in a hot water bath until crisp-tender, then finished with a quick sear or toss in a hot pan. It’s the same butter-tossed green bean side found on countless dinner tables, just cooked with more precision than boiling or steaming allows.

The bag holds everything the beans need: butter for fat, salt for seasoning, and a little garlic if you want it, all sealed in so the beans cook directly in that liquid instead of being tossed with it afterward. The same method takes well to other flavor directions once you’ve got the basic technique down - citrus zest and toasted nuts, chili-garlic for a Szechuan-style version, or garlic, anchovy, and Parmesan for something more savory.

The water bath runs far hotter than it would for meat or fish, into the mid-180s°F, because green beans need that heat to break down pectin in their cell walls and turn tender rather than staying raw-crunchy indefinitely. Since the water never approaches a boil, the beans keep a brighter color and a firmer bite than boiled or steamed beans, with a wide margin for error on timing.

The finishing step is what separates this from plain blanched beans in a bag: emptying the bag into a hot skillet and searing the beans for a minute or two concentrates the buttery liquid into a light glaze and adds a bit of browning. Skipping the sear and just tossing the warm beans with a garnish works too, for a lighter, more hands-off finish.

Serve them alongside roast chicken, a weeknight steak, or as part of a holiday spread. They’re an easy, mostly hands-off side, and the bag can be cooked ahead and finished in the skillet right before serving.

Ingredients

Serves 4

450 g green beans, trimmed
28 g unsalted butter
3 g kosher salt, plus more to taste
black pepper, freshly ground, to taste
1 small garlic clove, minced (optional)
lemon zest (or chopped fresh herbs, or toasted nuts), for garnish (optional)

Directions

Preheat a sous vide water bath to 185°F (85°C).

Trim the green beans, then combine them with the butter, salt, a few grinds of black pepper, and the garlic, if using, in a vacuum bag or a zip-top bag. Spread the beans into a single, even layer no more than about 1 inch (2.5 cm) thick so every piece cooks at the same rate.

Seal the bag, either with a vacuum sealer or using the water displacement method for a zip-top bag.

Submerge the bag in the water bath and cook for 45 minutes for a classic crisp-tender bean, 30 minutes for a firmer, snappier bite if the beans are very fresh, or up to 1 hour for a softer result.

Empty the whole bag, beans and buttery liquid together, into a hot skillet set over medium-high to high heat. Toss or sear for 1 to 2 minutes, just until the beans are lightly browned in spots and any excess liquid has reduced.

Season to taste with salt and pepper, add the garnish if using, and serve right away.

Notes

Green beans need a much hotter water bath than meat or fish, 183–186°F (84–86°C) versus roughly 130–160°F (54–71°C) for most proteins, because that heat is what breaks down pectin in the bean’s cell walls. Below it, beans stay crunchy no matter how long they sit in the bath.

Because the water never approaches a boil, sous vide green beans keep a brighter color and firmer bite than boiled or steamed beans, with a wide margin for error on time - an extra 15 to 20 minutes in the bath won’t ruin them the way it would on the stovetop.

The sear is optional. Tossing the just-cooked beans with a garnish straight from the bag, no pan needed, is a lighter finish that several recipes use instead.

For a fully soft, stewed texture instead of crisp-tender - beans braised in a tomato-onion sauce, for example - push the water bath to 194°F (90°C) and the time to 2 to 3 hours. It’s a legitimately different, softer style of dish, not a mistake.

The bag can go straight into an ice bath and then the refrigerator after cooking, still sealed, for finishing later.