Sous Vide Corn on the Cob: Temperature and Time

Sous vide corn on the cob cooks at 183°F (83.9°C) for 30 to 45 minutes. The kernels come out tender with a bright, fresh crunch. The bag has to be weighed down, because corn floats.

Temperature and time for corn on the cob

The calculator has one setting for corn on the cob.

The minimum is 30 minutes and the best window is 30 to 45 minutes. The time is for whole ears. Thickness is not an input for corn in the calculator.

The calculator sets no maximum for corn. Where a maximum would go, it shows "No limit, gets softer", and its note is that the upper time is a texture guide, not a limit.

The texture does change with time. The calculator's note for corn is that it turns soft after about an hour at this temperature. Anova's vegetable guide describes corn left in the bath too long as a little mushy after about an hour, though still edible.

Why the bath is so hot

J. Kenji López-Alt's sous vide corn recipe explains that corn contains a lot of pectin, the carbohydrate that holds vegetables together. He writes that pectin does not break down until around 183°F (83.9°C), so corn will not turn tender in a cooler bath.

Douglas Baldwin's guide to sous vide cooking states that most vegetables need much higher temperatures than meat and must be cooked separately. Corn cannot share a bath with ribs or a steak. The same goes for shrimp, which cook at 125°F to 140°F (51.7°C to 60°C) for 15 to 30 minutes.

It can share one with other vegetables. Potatoes, carrots and asparagus all use the same 183°F (83.9°C) bath, so each bag can go in and come out on its own time. The vegetables chart covers the other vegetables in the calculator.

Butter in the bag

Two published recipes use the same amount of butter in the bag:

The two recipes differ slightly on the bath. López-Alt cooks the corn at 183°F (83.9°C) for 30 minutes, and America's Test Kitchen at 185°F (85°C) for 40 minutes. Both times fall inside the calculator's 30 to 45 minute window.

The butter melts in the bath and surrounds the ears for the whole cook. Anova's guide adds a reason to include fat when you use aromatics: it helps their fat-soluble flavors move into the vegetable.

López-Alt lists cilantro, scallions, garlic and dried chiles as options and says to add them sparingly. His guideline is a few sprigs of herbs or half a split dried chile.

Husk on or off

Both recipes allow the husk to stay on. López-Alt makes it optional, with both ends of the ear trimmed. America's Test Kitchen's butter-poached corn leaves the husk and silk on, and says this adds subtle grassy notes and makes the corn far easier to peel afterward.

For a grill finish the husk has to come off before the ears go over the heat. You can shuck before bagging or after the bath.

How to sous vide corn on the cob

1. Heat the bath. Set the circulator to 183°F (83.9°C).
2. Prepare the ears. Shuck them, or trim both ends and leave the husk on.
3. Bag in a single layer. Add the butter and salt. López-Alt divides 4 ears among 1 to 2 vacuum-seal bags or 2 to 3 zipper-lock bags.
4. Seal. Use a vacuum sealer, or seal a zipper-lock bag with the water displacement method. America's Test Kitchen double bags, and Anova's guide warns that zipper seals can break at high temperatures.
5. Weigh the bag down. Attach a weight before the bag goes in. The next section covers the options.
6. Cook for 30 to 45 minutes.
7. Serve or grill. Open the bag, remove the husks if you left them on, and discard any aromatics. Serve with more butter, or move the ears to a hot grill.

Keeping the bag from floating

America's Test Kitchen notes that corn tends to float in a water bath, which leads to uneven cooking. The kernels above the water line are not at the bath temperature.

Jason Logsdon's article on floating bags at Amazing Food Made Easy lists three causes: air left in the bag, food that is buoyant, and gas that vegetables give off as they cook. Baldwin adds a fourth at high temperatures. Some of the liquid in the bag turns to vapor, and the bag puffs up.

Ways to hold the bag under:

• Clip on a weight. López-Alt clips a heavy metal spoon or knife to the edge of each bag with a heavy-duty binder clip.
• Put a weight inside the bag. Logsdon lists butter knives and pie weights. Anova's guide also suggests a weight inside the bag or clipped to the outside.
• Use a rack. Baldwin holds bags under with a wire rack. Anova's guide mentions a pot lid rack.
• Set something on top. Logsdon lists a heavy ceramic plate or bowl, or a metal pot lid.

A bag can puff up partway through the cook. Look at it after the first few minutes and add weight if any part of an ear has risen above the surface.

Finishing on the grill

The corn is fully cooked when it leaves the bag, so the grill only has to char the surface.

Anova's vegetable guide gives this method for grilling vegetables after the bath:

1. Light the charcoal, or set half the burners of a gas grill to high. Cover and preheat, 5 minutes for charcoal or 10 minutes for gas.
2. Clean and oil the grates.
3. Grill over the hot side for 45 seconds to 1 minute per side.

Brush on butter after the grill. America's Test Kitchen brushes its ears with softened butter and seasons them after the bath.

Cooking corn from frozen

The calculator's corn times are for corn that is not frozen. Its instruction is to thaw the ears first, then cook for the normal 30 to 45 minutes.

The guide to cooking from frozen covers the foods that can go straight from the freezer into the bath.

Safety

The calculator lists no safety warnings for corn on the cob. It does not apply a pasteurization table to it, and it shows the pasteurization status as not applicable.

Submersion is the point that applies. Baldwin's guide says pouches must be completely submerged and not tightly arranged or overlapping, to prevent undercooking. Logsdon makes the same point about floating bags: food out of the water is not held at the proper temperature. The broader rules are in is sous vide safe.

Common problems

The corn is soft and mushy. It stayed in the bath too long. The calculator's note is that corn turns soft after about an hour at this temperature, so take it out within the 30 to 45 minute best window.

One side of the ear is firmer. That side floated above the water. Add weight and keep the ears in a single layer.

The bag leaked. A zipper seal opened in the heat. Double bag, or use a vacuum-seal bag.