Freezing is one of the easiest and most flexible preserving methods - when you’re ready to eat something, you simply thaw it and finish it – and then you can replace the space it took up in your freezer with a new item. It is also one of the most effective preserving methods, because it successfully stops spoilage, decay, and bacterial growth, extending shelf life of most foods to their greatest possible extent.
When you freeze food, all of the moisture in the food is also frozen. Without moisture, bacteria fails to grow, and without warmth, spoilage is brought to a halt, thus preserving food’s flavor, texture, and overall quality. However, the quality of frozen food can deteriorate in a number of ways. If frozen too long, its flavor and texture when thawed will suffer. If food is thawed or partially thawed and then refrozen, its flavor and quality will suffer. In general, food should be kept frozen until ready to used, safely thawed, and then used as soon as possible. Also remember that frozen foods will have the best flavor and texture if frozen at their freshest – so freeze foods within four days of purchasing.
Most vegetables and fruit freeze well, and freezing preserves their natural colors, flavors, and nutritional value. There are several ways to freeze produce, depending on how you plan on using the food once it is thawed.
- Individually Quick Frozen (IQF) food is the process by which produce and other food is quickly frozen to keep each piece separate in the packaging. This is ideal for all kinds of produce, both frozen whole (peas, strawberries, green beans) and in pieces (peaches, bell peppers, apples). You can recreate this technique at home (see below).
- You can also freeze cooked produce - this is ideal for some foods that don’t freeze well raw, like tomatoes. It’s also excellent as a method of storing prepared foods – you can freeze jam, fruits in syrup, sauces, and soup bases made from different types of produce.
While freezing is an easy and versatile freezing preserving technique, it does not work for everything. The following are some items that do not freeze well:
- Celery
- Melon
- Cucumber
- Scallions
- Radishes
- Lettuce
- Raw tomatoes (tomatoes may be frozen raw if they are to be used in cooked preparations later, like chili or tomato sauce).
Individually Quick Frozen (IQF) foods are foods frozen in a single layer so that they remain separate. This technique is easy to re-create in small batches in your own freezer. Keep baking sheets in the freezer until ready to freeze the food. Place the food onto the baking sheet, keeping pieces separate and in a single layer. Freeze food until it’s solid – at least one hour. Once the food is fully frozen, transfer it to the proper storage container and label it. This technique works with a variety of foods. You can use foods that are kept whole (such as strawberries or peas), foods that are fabricated in some way (halved peaches or diced carrots), or even foods that have been blanched or par-cooked (potatoes or greens, like kale or Swiss chard).
IQF fruit and vegetables will keep frozen for up to 8 months. Once thawed, they should be used within 1-2 days.