Sous vide translates literally to “under vacuum” as it involves cooking food in plastic bags that are vacuum sealed and cooked in water baths at precise temperatures. The technique, however, is much more useful for the temperature control elements than the vacuum. The reverse sear method mimics the temperature control element of the technique, but is just done in an oven, so it’s very much not under a vacuum.
> The technique, however, is much more useful for the temperature control elements than the vacuum
The vacuum sealing (which doesn’t actually leave a vacuum, because its not done in a rigid container, so name aside, sous vide cooking is not, in any substantive sense, cooking under vacuum) is a technique in achieving temperature control, because it means the food is in direct contact with the bag which is in direct contact with the water bath, rather than there being air in the bag insulating the food from the water bath.
> The reverse sear method mimics the temperature control element of the technique, but is just done in an oven, so it’s very much not under a vacuum.
In an oven, the food is in direct contact with the thermal medium without a layer in between, but the thermal medium is air rather than water; air has a similar specific heat but much lower density than liquid water at constant pressure, so even if your heat control is as good as in a sous vide system (with most ovens, it is not) you still aren’t really getting the same effect. Reverse sear is a faster, hotter, less even method than sous vide, with the advantage (for steaks, and things where this is an advantage) of producing greater surface evaporation which provides a better sear.
