8 Foods You Should Never Freeze

Bananas about to go bad? Hamburger rolls on sale? Have leftover soup? They can all go in the freezer. The range of things you can stash in there is amazingly versatile, and freezing can be an easy way to lengthen the shelf life of foods, prevent leftovers from going to waste and save time on prep work during busy weekdays. In fact, it's so easy, we can sometimes forget that not everything does well in sub-0 degree F temperatures.

"Anything can freeze, but the quality of certain foods will deteriorate," says Jonathan Deutsch, Ph.D., a professor at Drexel University and director of the Drexel Food Lab. What happens is this: Water expands when frozen, and at the cellular level, that results in burst cell walls and a resulting change in texture, which is why defrosted items can sometimes seem soggy.

Improperly wrapped foods are also subject to freezer burn, which means that they have been exposed to oxygen, which can alter their taste and appearance, and leech water from the food so it's dried out. Foods may also develop an off taste due to absorbing other odors from the freezer (a good reason to keep an open box of baking soda in there). But even properly wrapped, the following foods can be problematic to freeze and thaw:

Lettuce

"Once frozen, the burst cell walls will result in a lettuce leaf that has gone from crisp to mushy and translucent," says Deutsch. While you definitely wouldn't want to freeze romaine or iceberg lettuce, there are some exceptions to this rule. Greens like chard, spinach and kale can be frozen; you just have to know the right way to do it. We've outlined the technique here for whenever your green smoothie craving strikes.

Sauces or Gravies

If they've been thickened with a starch like cornstarch, Deutsch says, they may end up watery. Freezing weakens the bond between the starch and any moisture it absorbs, making your sauces and gravies much thinner.

Pudding

If you've made pudding at home and it's been thickened with a starch, you'll run into the same problem as you do with sauces and gravies, Deutsch says.

Cream-Based Soups

While soups and stocks freeze tremendously well, anything with dairy runs the risk of curdling or separating, according to the National Center for Home Food Preservation.

Non-Fatty Fish

Without fat to act as an insulator, fish can get waterlogged, says chef Frank Proto. Use up leftover fish to top your salad or whir it into a dip.

Cooked Pasta or Rice

These starches can freeze, but attempting it isn't ideal, says Proto. When they thaw and the cell walls break, they'll seem overcooked and flavorless. We have tons of tasty ways to use up rice or leftover pasta (Spaghetti Frittata, anyone?).

Cooked Egg Whites

While raw eggs or whites freeze beautifully, cooked ones can get rubbery due to the lack of fat (yolk) says Proto. Stick to recipes that call for the whole egg if you want to freeze them, like quiches or egg cups.

Mayonnaise or Mayo-Based Dressings

The emulsions in mayonnaise will break, or have the fat separate from the other ingredients, says Proto.