I have frozen leftover homemade soup, such as chicken noodle and vegetable beef. When I reheat it, the veggies always seem mushy. Is there any way to freeze and reheat soup and avoid this, or do I just need to make the right amount to be eaten without freezing?
Soups freeze particularly well for the most part. I make both the kinds you mention for clients regularly; often half is refrigerated and half is frozen for later consumption, and there are no complaints.
Use fresh vegetables, not frozen. Because frozen vegetables are blanched to maintain their quality in the freezer, they’re already partially cooked and easily overcooked. Cool the soup quickly as described in the next paragraph when it’s done; don’t allow it to sit on the turned-off burner or even on the counter. Carry-over cooking will render many vegetables mushy quickly.
Certain vegetables overcook easily, whether they’re frozen or not. Asparagus, zucchini, and summer squash come to mind. What I do if they’re called for in a recipe is remove the amount of soup that’s to be frozen and chill it in an ice bath. Draw a sink full of cold water, add ice, and put in the container with the soup into it. Allow to cool, stirring from time to time to equalize the temperature, and then add that particular vegetable. It will cook through when the soup is reheated.
Sturdy greens like kale and collards freeze well in soup because of their cooking time. Spinach wilts almost as soon as it hits the hot liquid, so unless it’s puréed, this is better added when reheating the soup.
Potatoes don’t generally freeze well unless mixed with fat or dairy products. If you want to include them, use a low-starch potato and undercook. Or, as potatoes keep well at room temperature, add them when you reheat the soup. Figure the cooking time into your reheating calculations. You may want to parboil them in water or stock before adding to the soup. Timing will depend on the size of the cubes. Starches like pasta and rice get waterlogged if allowed to sit in liquid. Treat them like potatoes.
Freeze soup in containers which hold the amount of soup you think you’ll want. Don’t freeze in quart size containers if you’ll only want a pint at a time. It may save a little space in the freezer, but you’ll have to defrost the entire amount to get what you need. The quality of the soup not eaten may suffer. If you’re not sure, freeze in two pint size containers; that way you have to option to thaw one or both, depending on the need.
Lastly, remember that not all vegetables in soup need to be as crisp as you’d like on your plate. Especially with a soup like beef-vegetable or minestrone, you’ll get a mouthful of different kinds in each spoonful, so each one need not be perfectly cooked. I often make a flavor base of diced carrot, onion, and celery cooked in butter or olive oil to start a soup; and by the time the soup’s done, these will definitely be overcooked. It doesn’t matter. They add flavor and bulk without texture, and that’s fine. Texture comes from the same vegetables, cut larger and added later, and from the meat in the soup. It’s the overall mouth-feel that counts.