Continuing experiments in sous vide: I asked myself whether a roast can be divided and cooked to two precise levels of doneness in one hot water bath? Yes you can. Here’s how …
Cook both pieces to the lower temperature, remove the rarer piece, raise the temperature for a couple of hours to the second level, then replace enough hot water with cold to drop back to the lower temperature and continue cooking both pieces for the ideal amount of time for tenderness.
Wrap the removed piece of roast in an insulating material (e.g. blanket, bubblewrap etc.) to ensure its temperature doesn’t drop to dangerous levels while out of the bath.
This tri-tip was carved into pieces along the grain, marinated in a dry coffee rub and blacked on the stovetop before being poached to ensure even the savory crust was juicy and tender — and so the taste could penetrate deeper into the roast. The rare section was cooked at 60˚C for 4 hours, removed and insulated while the medium section was cooked at 70˚C for just 2 hours — then after the water was cooled back down to 60˚C both were cooked for a further two hours. Eight hours in total for the medium roast and just 6 hours for the rare.