Sous Vide Potatoes

January 23, 2012

Sous Vide Potatoes

Sous vide potatoes are small waxy potatoes, sealed in a bag with butter, olive oil, salt, and a sprig of herb, cooked in a hot water bath until fully tender, then finished with a hard sear in a hot skillet for a crisp, golden crust. It’s the sous vide answer to a good pan-fried or roasted potato: the same handful of ingredients, but every piece comes out of the bath cooked exactly as far as it should be, with no undercooked centers or blown-out edges. The result is rich and buttery inside, faintly perfumed by the herb, with a salty, crisp crust from the sear.

The bag does double duty as cooking vessel and seasoning step: butter and oil coat the potatoes, salt seasons them through, and the herb, or garlic, perfumes the liquid as everything cooks together. Cut size matters more than the exact seasoning - halve or cube the potatoes into even, bite-size pieces so they all reach the same doneness at once, and leave very small ones whole. Because potatoes float, the bag needs a clipped-on weight or a sous vide weight tray to stay fully submerged for the whole cook.

The water bath runs hot for a vegetable, into the high 180s or low 190s°F, because potatoes need real heat to break down their pectin and starch and turn tender, well above the temperatures used for meat, fish, or more delicate vegetables. Since the water never boils, the potatoes hold their shape through the whole cook, and there’s none of the waterlogged, blown-apart texture that comes from boiling loose in a pot of water.

There’s no traditional version of this dish to speak of - sous vide is a modern precision-cooking method, and applying it to potatoes is really a way of guaranteeing a good result before the pan or oven ever gets involved. It belongs to the same wave of home sous vide cooking that popularized bagged carrots, corn, and eggs: cook the vegetable perfectly in the bath first, then finish it however it would be finished on any other night.

Serve seared sous vide potatoes alongside steak, roast chicken, or a fried egg at breakfast, or skip the sear and serve them butter-poached straight from the bag as a softer side. They also make a good starting point for a warm potato salad - toss the just-cooked potatoes into a vinaigrette while they’re still warm instead of searing them.

Ingredients

Serves 4

680 g small waxy potatoes (Charlotte, new potatoes), halved if larger than bite-size
28 g unsalted butter
15 ml olive oil
12 g kosher salt
1 g black pepper, freshly ground
1 sprig fresh thyme (or rosemary, or 2-3 cloves garlic, smashed)
15 ml avocado oil (or other high-smoke-point oil), for searing
flaky salt, to finish

Directions

Preheat a sous vide water bath to 190°F (88°C).

Cut the potatoes into even, bite-size pieces - halves or 1 to 1.5-inch (2.5-4 cm) cubes - so they all cook at the same rate; very small new potatoes can go in whole.

Combine the potatoes, butter, olive oil, salt, pepper, and the herb, or garlic, in a vacuum-seal or zip-top bag. Seal with a vacuum sealer, or use the water-displacement method for a zip-top bag.

Submerge the bag in the water bath, weighting it down since potatoes float, and cook for 1 hour. Small or thinly cut pieces are done in about 45 minutes, while whole larger potatoes can take up to 1½ to 2 hours.

Remove the bag from the bath. If not searing right away, chill it in an ice bath and refrigerate for later.

Heat the avocado oil in a cast iron skillet over high heat. Add the potatoes cut-side down and sear for 1 to 3 minutes per side, until golden and crisp. For an oven or air fryer finish instead, roast at 450°F (230°C) or air-fry at 400°F (200°C) for 10 to 15 minutes.

Season with a pinch of flaky salt and serve hot.

Notes

Potatoes need a much hotter water bath than meat, fish, or delicate vegetables: 183°F (84°C) is the practical floor, since below it the pectin holding potato cells together never fully breaks down, no matter how long they cook. From there, texture scales with temperature - 183°F (84°C) holds a firm, salad-ready shape, 190°F (88°C) is the standard, fully tender default, and up to 194°F (90°C) pushes toward a soft, near-mashable texture.

Waxy, small potatoes like Charlotte or new potatoes hold their shape best through the bath and the sear. Starchy potatoes like russets suit the higher end of the range better, especially if the end goal is mash or purée rather than a shaped side.

Skip the sear to serve the potatoes butter-poached straight from the bag, or toss them warm into a vinaigrette for a warm potato salad - both are legitimate finishes, not compromises.

Pre-cooked, unseared potatoes keep well: refrigerate up to 5 days or freeze up to 3 months, then reheat briefly in a 190°F (88°C) bath before searing or serving.