Sous Vide Potatoes: Temperature and Time

Sous vide potatoes cook at 183°F (83.9°C). Pieces up to 1 in (2.5 cm) thick take 30 minutes to 1 hour. Pieces of 1 to 2 in (2.5 to 5.1 cm), or small whole potatoes, take 1 to 2 hours at the same temperature. They come out of the bag tender all the way through, ready to roast, smash or mash.

Temperature and time for potatoes

The calculator has two potato settings. Both use the same bath temperature, and the size of the pieces decides the time.

Thickness is not an input for potatoes in the calculator. Choose the setting by what goes in the bag:

• Pieces up to 1 in (2.5 cm): minimum 30 minutes, best window 30 minutes to 1 hour. The texture is tender all the way through and still holding its shape.
• Pieces of 1 to 2 in (2.5 to 5.1 cm), or small whole potatoes: minimum 1 hour, best window 1 to 2 hours. The texture is tender all the way through.

Neither setting has a maximum. Where a maximum would go, the calculator shows "No limit, gets softer". Its note is that the upper time is a texture guide, not a limit, and that longer cooking only makes the food softer.

Carrots use the same bath temperature, as does corn on the cob, which takes 30 to 45 minutes, and the vegetables chart covers the other vegetables in the calculator.

Why the bath is so much hotter than for meat

Douglas Baldwin's guide to sous vide cooking explains that meat temperatures are too low to soften the starches and cell walls in vegetables. He states that most vegetables need much higher temperatures than meat and have to be cooked separately.

Anova's vegetable guide names the substance involved. It describes pectin as a glue that holds plant cells together, and says it does not break down until 183°F (83.9°C).

This means potatoes cannot share a bath with a steak. Cook the potatoes in their own bath, or cook them first and finish them in the oven or a skillet while the meat is in the water. The same applies to corned beef, which is often served with potatoes: its settings run from 135°F (57.2°C) to 176°F (80°C), all below the potato bath.

Cut size

The calculator's note on the setting for pieces up to 1 in is to cut the potatoes into even pieces so they cook at the same rate. A bag with mixed sizes gives you soft small pieces and firm large ones at the same moment.

Jason Logsdon's vegetable guide at Amazing Food Made Easy cuts vegetables into cubes of 1/2 to 1 in (1.3 to 2.5 cm) and places them in the bag in a single layer. Anova's guide suggests cooking vegetables in the shape you plan to serve and fitting them in a tight single layer.

A piece thicker than 1 in, or a small whole potato, needs the longer setting because heat has to travel from the surface to the center. Cutting the potato shortens that distance, which is why pieces up to 1 in use the 30 minute to 1 hour setting. Neither setting describes a large whole potato, so cut it into pieces of 2 in (5.1 cm) or less.

Waxy or starchy potatoes

The type of potato changes the cooked texture. America's Test Kitchen's article on potato starch sorts common potatoes into three groups:

The article gives the mechanism. High-starch potatoes absorb more water as they cook, and their cells swell and push apart. In low-starch potatoes, pectin released from the cell walls forms a gel that holds the cells together.

Use that to match the potato to the dish. The article recommends red potatoes for boiling and salads, where pieces have to stay intact, and russets for mashing. America's Test Kitchen's own sous vide recipes use small red potatoes for smashing and Yukon Golds for a puree.

How to sous vide potatoes

1. Heat the bath. Set the circulator to 183°F (83.9°C).
2. Prepare the potatoes. Scrub them. Leave small potatoes whole or halve them, and cut larger ones into even pieces no more than 2 in (5.1 cm) thick.
3. Season and bag. Arrange the pieces in a single layer. Anova's guide adds salt and a fat such as butter or oil to the bag, with aromatics as an option.
4. Seal. Anova's guide warns that zipper-lock seals can break at high temperatures and recommends vacuum-seal bags. If you seal a zipper-lock bag with the water displacement method, double bag it, which is what America's Test Kitchen does in its smashed potato recipe.
5. Submerge and weigh down. Lower the bag in and hold it under water with a rack or a weight.
6. Cook. 30 minutes to 1 hour for pieces up to 1 in, 1 to 2 hours for pieces of 1 to 2 in or small whole potatoes.
7. Check and finish. Open the bag and pierce a piece with the tip of a knife. It should be tender all the way through. Then roast, smash or mash.

Finishing: roasting, smashing and mashing

Browning in a skillet or under the broiler. Anova's guide heats oil or butter in a cast iron or stainless steel skillet over medium-high heat and stirs the vegetables until browned, 3 to 5 minutes. Its broiler method takes 2 to 5 minutes on the top rack.

Smashing. America's Test Kitchen's crispy smashed potatoes use small red potatoes 1 to 2 in (2.5 to 5.1 cm) across. After the bath they are drained, tossed in oil, pressed between two baking sheets until 1/3 to 1/2 in thick, and roasted at 450°F (232°C) for 40 to 50 minutes with one flip.

Mashing. America's Test Kitchen's French-style mashed potatoes slice Yukon Golds 1/4 in (0.6 cm) thick and seal them in the bag with butter, milk and salt. The recipe says cooking the potatoes in the milk and butter concentrates the potato flavor and cooks them evenly. They then go through a food mill or ricer.

Cooking potatoes from frozen

The calculator's potato times are for potatoes that are not frozen. Its instruction is to thaw them first, then use the normal time for their size.

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

Safety

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

The point that does apply is submersion. Baldwin's guide says pouches must be completely submerged and not tightly arranged or overlapping, to prevent undercooking. A potato piece sitting above the water line stays below the bath temperature and stays firm. The broader rules are in is sous vide safe.

Common problems

The bag floats. Baldwin notes that at high bath temperatures some of the liquid in the bag turns to vapor, so the bag puffs and may rise. He holds bags under with a wire rack. Anova's guide suggests a weight inside the bag or clipped to the outside, or a pot lid rack. Logsdon suggests a plate or a lid on top.

The seal opens. Anova's guide says zipper-lock seals can break at high temperatures. Use a vacuum-seal bag, or double bag a zipper-lock bag.

Some pieces are still firm. The pieces were uneven, stacked, or too large for the setting. Cut to one size, keep a single layer, and use the 1 to 2 hour setting for pieces thicker than 1 in and for small whole potatoes. If the pieces are still firm at the end of the window, leave them in longer.