Sous-vide Time by Temperature and Thickness

Sous-vide cooking time by thickness

With sous-vide, you seal food in a vacuum bag and drop it into a water bath held at the core temperature you want. What sets the time is heat conducting into the meat, not the bath temperature itself. Treat the cut as a thick slab and the one-dimensional heat equation gives an equalization time that scales roughly as t ≈ ρ·c·d²/α, where d is the thickness, ρ the density, c the specific heat and α the thermal diffusivity of the meat (~1.4×10⁻⁷ m²/s for beef).

In the kitchen, cooks just read off tabulated values like the ones Douglas Baldwin compiled (A Practical Guide to Sous Vide Cooking) or those in the Modernist Cuisine volumes. A beef tenderloin steak at 54°C runs about 30 minutes at 1 cm thick, around an hour at 2 cm and roughly 2 hours at 4 cm. Pasteurization follows its own kinetics, separate from all that. The D-value (time for a 10-fold drop in pathogens at a given temperature) and z-value (the temperature shift that changes D by a factor of 10) tell you how long the core has to stay hot to be microbiologically safe.

Applications

Fine-dining mise-en-place, professional banquet service (par-cook then sear à la minute), batch meal prep at home, recovery diets that call for very tender protein, and anything where you want even doneness from edge to edge. The textbook example is a thick ribeye that reads medium-rare all the way through.

FAQ

Why does thickness matter much more than weight? Heat moves in from the surface, and the last spot to catch up is the geometric center. Two steaks of equal mass but different thickness end up cooking in very different times.

Can I leave the meat in too long? Past about 4 hours at low temperatures the texture turns mushy as collagen and protein fibers keep breaking down. Tough cuts (chuck, brisket) are the exception and benefit from 24-48 h at 60-68°C.

Do I still need to sear afterwards? Yes. Sous-vide never hits the Maillard reaction, which needs >140°C. A fast sear in a screaming-hot pan or with a torch builds the crust without overcooking what is inside.