Preparing food ahead of time and reheating it later is a fundamental skill for professional cooks, and it's pretty useful for home cooks as well. When mealtime rolls around, you can be poised and confident knowing that the bulk of your work is done and there shouldn't be any unhappy surprises. For example, you might prepare your roast the previous day, then refrigerate it until needed. The key to doing this successfully is close attention to food safety. Cooling and reheating meat safely requires proper monitoring of time and temperature.
Cooking and Cooling
Select your roast with cooling and reheating in mind. The shape is more important than weight. Roasts cut in a relatively flat or cylindrical shape will cook, cool and reheat more readily than round or square cuts.
Season and prepare the roast using your favorite recipe. Remove it from the oven when it reaches a degree of doneness just lower than your usual preference. For example, if you like your beef medium, you should take it out while it's medium-rare. Pour off and refrigerate the drippings.
Transfer the roast to a large plate or serving platter and place it in a well-ventilated spot. Insert an instant-read thermometer into the thickest part of the roast. It should cool to 70 degrees Fahrenheit within two hours to remain within food safety guidelines. If the roast weighs 4 pounds or more, it's best to cut it into smaller pieces of approximately 2 pounds.
Wrap the cooled pieces of roast in airtight packaging, such as plastic film wrap, and place them in your refrigerator. Distribute the pieces of roast into the back corners of your fridge, where the air is coldest and the opening and closing of the door will have the least effect.
Refrigerate the roast overnight, or until needed.
Reheating the Roast
Preheat your oven to 350 degrees Fahrenheit. Remove the roast or pieces of roast from your refrigerator and and unwrap them.
Set out one square of heavy-duty foil on your countertop for each piece of roast, and line it with a piece of parchment paper. Place a piece of roast on each. Remove the solidified fat from your reserved drippings, and top each piece of roast with 2 to 3 tablespoons of drippings. Lift the edges of the foil, and roll and crimp them to make a tight parcel.
Put the parcels of foil-wrapped roast on a baking sheet and transfer them to the preheated oven. Reheat for 20 to 25 minutes, until an instant-read thermometer inserted into the middle shows that the roast has fully reheated.
Rest the pieces of roast in their wrappings for five to 10 minutes, then unwrap and carve them.