What are the pitfalls of freezing and reheating casseroles with raw and cooked ingredients for later use?

Question

Cooking for a ranch here. We'll be slammed soon. One self-trained cook, well-appointed kitchen, multiple chest freezers, 30-40 hungry guests for two weeks straight. What are the pitfalls of preparing and freezing casseroles containing cooked and raw ingredients for later use? I'm talking lasagna, fire station casserole, green bean casserole, quiches, etc. Lasagna for instance: cooked meat sauce, everything else is raw. Thank you.

Answer 1

From a food safety standpoint, you're going to be how long the middle of the casserole is in the 'food danger zone' both cooling and reheating.

Because of this, you don't want to make too deep of casseroles (thinner casseroles freeze and reheat faster), and in cases with a sufficiently thick top (tater tot casserole, shephard's pie), you may even want to freeze them without it, so you can warm them separately and then combine.

I would also recommend allowing the ingredients to cool some before assembly. As you're not relying on the hot ingredients to spread their warmth to the other ingredients, you want to let them cool to just above 140°F (maybe 150°F for working time), then assemble everything and get it into the fridge to chill (or even straight to the freezer, see note about containers below)

If your ingredients can be assembled cold, then you may want to chill them first instead. This doesn't work with all sauces, as some will thicken up and make them difficult to spread. (eg, refried beans in an enchilada casserole)

You should also consider what containers you're using. Many ceramic dishes can't handle the thermal shock of going straight from hot to the freezer, or from frozen to a hot oven. Metal or even disposable foil pans (with support underneath) may be a better option. If you absolutely have to reheat directly from frozen in a ceramic pan, put a sheet pan on the shelf below and put the casserole in a cold oven and then start preheating it. Putting the dish directly on the sheet pan can act as a heat sink and cause extra thermal stresses.

I would personally try to move the casseroles to the fridge a day or two before you plan on baking it. This allows it to thaw some, reducing the chance of breaking your casserole dish, and to heat through more quickly.

You'll want to heat the casserole until it reaches the necessary safe temperature for the riskiest ingredient (usually a meat, poultry, pork, chicken, etc). My family usually heats things slowly (about 350°F, covered), until it's sufficiently heated, then brown it under the broiler (top heat only at higher temperature). I suspect this may not be as safe as heating at a higher temperature (maybe 400-425°F, and starting uncovered if you're using foil)

To deal with the possibility of the casserole being dry from overcooking, I would have some sort of extra sauce available for people to add. Tomato sauce, bechamel (white sauce), gravy, salsa, etc.

I would also recommend looking for recipes specifically intended for freezing and reheating, and see if they have specific tips or just how they vary from your normal recipe. Some keywords to use include "freezer cooking", "make-ahead cooking" or "make now, serve later" or "once a month cooking". There are cookbooks that use these terms, but before you order online, be aware that some of these may just be intended for a day or two in the fridge and not necessarily freezing.

As one example, I've never done it, but if I was going to make a quiche to freeze, I would make it without the custard... then heat it in the oven while mixing the eggs and milk, then pour that over the thawed ingredients and finish cooking it.