Sous Vide Corn on the Cob

October 16, 2015

Sous Vide Corn on the Cob

Corn cooked in a water bath comes out evenly tender from the first row of kernels to the last, with none of the gamble that boiling or grilling carries - no scorched patches, no ears that are mushy at one end and starchy at the other. The method is simple: husked ears go into a bag with butter and a little salt, then into water held at a steady temperature until the kernels give way to a bite.

That steady temperature matters more than it sounds like it should. Corn’s pectin, the substance that holds its cell walls firm, doesn’t start breaking down until the water passes about 183°F (84°C). Below that line, no amount of extra time will make the corn tender - it just sits there being crunchy. Above it, the kernels soften on schedule and the butter in the bag melts into a light baste that coats every ear by the time it comes out.

Corn is also stubbornly buoyant - the air trapped in the kernels makes a bagged ear float right to the surface, which leaves the top exposed to cooler air above the water line and cooks it unevenly. A simple weight clipped to the bag keeps everything submerged and solves the problem completely.

Serve the corn straight from the bag, drizzled with the butter that pooled around it - sweet, buttery, and tender enough to strip clean off the cob in one bite. Or run it over a hot grill for a minute or two afterward for char and grill marks. Either way it makes a natural side for burgers, ribs, or anything else off the grill, suiting a backyard cookout as easily as a weeknight dinner - corn on the cob, done properly, every time.

Ingredients

Serves 4

4 ears corn, husked and silk removed
28-56 g unsalted butter
salt, to taste
black pepper, optional
1 sprig cilantro, optional
1 dried chili, split, optional

Directions

Preheat a sous vide water bath to 183°F (84°C).

Lay the corn in a vacuum-seal bag in a single layer with the butter and a pinch of salt, adding the pepper, cilantro, or chili now if using. Vacuum seal, or use the water displacement method with a zip-top bag: lower the open bag slowly into the water so the pressure pushes the air out, then seal it just before the top edge goes under.

Submerge the bag in the bath. Corn floats, so clip a weight - a butter knife, a small pot, or a sous vide weight - to the bag to keep it fully underwater.

Cook for 30 minutes. Anywhere from 25 to 40 minutes works depending on how fresh and sweet the corn is, and the bag holds safely for up to 90 minutes if the timing needs to flex.

Lift the bag out of the bath and take out the corn, reserving the butter left behind in the bag.

Serve right away, drizzled with the reserved butter and a little extra salt. For a charred finish, run the corn over a hot grill instead, turning every 30 to 60 seconds until grill marks appear on all sides, about 1 to 3 minutes total.

Notes

For a charred finish, grill the corn straight after the water bath - turn it every 30-60 seconds over high heat until marks appear on all sides, 1-3 minutes total.
Pectin doesn’t break down below about 183°F (84°C), which is why that’s the floor for this method rather than a starting suggestion - going lower leaves the corn starchy no matter how long it cooks.
Frozen corn on the cob works at the same temperature; add about 30 minutes to the cook time.
A husked ear of sweet corn weighs roughly 150-200 g, useful if scaling the recipe by weight.