Rich casseroles and casserole-like noodle dishes are classic forms of comfort food. They're also convenient to prepare in bulk, so you can package up the leftovers to provide several meals for later. Beef stroganoff is exactly that sort of meal, but it's not as straightforward to reheat as a lot of similar dishes. Its distinctive sauce is made with sour cream, which can curdle and become unappetizing if it's not re-warmed carefully.
First, Cool it Safely
No matter how you plan to store your stroganoff, the first step is to cool it safely. Bacteria can quickly colonize the beef and the rich sauce as it cools and reaches the upper end of the food safety "danger zone," at 140 degrees Fahrenheit. Two hours in the danger zone makes food unsafe, so your goal is to quickly lower the stroganoff's temperature to below 40 F.
- Transfer the meat and sauce to flat, shallow containers. The large surface area helps heat dissipate quickly.
- Make room for the containers in your fridge, distributing them around the shelves so they don't create a large warm spot in any one place.
- Leave the lids off your containers for the first hour, so warm air isn't trapped inside.
Storing Your Leftovers
The coldest area in your fridge is usually near the back corners of the bottom shelf, where cold air naturally settles. That's the best place to store your leftover stroganoff. It must be used within 3 to 4 days, so only refrigerate as many portions as you're able to eat during that time frame. The remainder should be packed in airtight bags or containers and frozen for later use. Leftovers in the freezer remain food safe indefinitely, but are at their best within the first few months. It's also good idea to date and label the packages when you freeze them, so you can tell at a glance by when you need to use them.
Thawing and Reheating
There are three ways to safely thaw frozen stroganoff: The best is to leave it in your refrigerator overnight, which allows the beef and sauce to thaw gently without ever reaching the food safety danger zone. You can even safely refreeze the stroganoff, if you decide not to cook it the next day. If you hadn't planned your meal that far ahead, the next-best option is to place the leftovers -- in a watertight bag or container -- into a large bowl full of cold water. Change the water every 20 to 30 minutes, until the stroganoff is largely thawed, and then reheat it. In a pinch, you can thaw it in the microwave as well, but once it's defrosted, you should continue to reheat it all the way to serving temperature. For leftovers, that means heating the entire dish to a minimum temperature of 165 F.
Rewarming stroganoff can be an iffy proposition because the sour cream that gives the sauce its distinctive flavor will tend to curdle or "break" if it gets too hot. There are a few ways to work around that problem. One is to drain the sauce away and reheat it separately, heating it gently and stirring frequently until it reaches the correct temperature. If you know in advance that you'll be reheating leftovers, you can thicken the sauce with a small quantity of flour or cornstarch. This stabilizes the cream and keeps it from breaking. Even better, separate a portion of sauce before you add the sour cream. When you heat your leftovers, you can fearlessly heat that sauce and then add sour cream just before serving, the same way you do when it's freshly made.