Sous vide ("under vacuum") means sealing food in a bag and cooking it in a water bath held at an exact temperature, often for a long time. A steak cooked at 131°F comes out the same pink from edge to edge.
Key idea
Safety comes from time at temperature. Either cook to the safe minimum internal temperature for that food, or follow a published time-and-temperature table. For example, the FDA Food Code's table for whole roasts of beef allows 130°F held for 112 minutes, 135°F for 36 minutes, 140°F for 12 minutes or 145°F for 4 minutes, counted after the center reaches that temperature.
| Roast temperature | Hold at least |
|---|---|
| 130°F | 112 minutes |
| 133°F | 56 minutes |
| 135°F | 36 minutes |
| 138°F | 18 minutes |
| 140°F | 12 minutes |
| 142°F | 8 minutes |
| 145°F | 4 minutes |
- Sear the outside after cooking for color; the bath can't brown food.
- If food is not served right away, chill it quickly by the two-stage cooling rule (ice water works well) and keep it cold.
- Use bags made for cooking.
- In restaurants, vacuum-sealing and sous vide are "reduced-oxygen packaging", and the Food Code requires a HACCP plan for them.
Why it works
Germs die faster the hotter they get. At 145°F a few minutes is enough; at 130°F it takes nearly two hours. Low temperatures are safe only when the time is long enough, and the time is measured at the center of the food.
Worked example: How long?
A beef roast's center has reached 135°F in a water bath. By the Food Code's table, how long must it hold there?
- Read the table: 135°F needs 36 minutes.
Answer: 36 minutes.
Common mistake
Starting the clock when food goes in the bath. The table's time starts when the center reaches the bath temperature, which can take an hour or more for thick pieces.
Practice at home
- If you have a circulator, cook one steak in a 145°F bath until its center reaches 145°F and cook another in a pan to the same reading. Slice both and compare how far the gray band goes.