Bean sprouts -- not to be confused with alfalfa sprouts which are commonly used in salads or sandwiches -- come from mung beans and are used in a number of Asian dishes. The bean sprouts can be used to make spring rolls, egg drop or hot and sour soup and stir-fries. By freezing the sprouts, you can keep them on hand throughout the year.
Bean sprouts lose some of their crispy texture when frozen because they have a naturally high water content. Blanching the sprouts first will help preserve some of that crunch.
Blanching stops vegetables from ripening further, preserving the texture and flavor while they're frozen. Bean sprouts only need a quick blanch in boiling water then an ice water bath. Immerse the bean sprouts in a pot of boiling water for 3 minutes, then remove them and immediately place in the ice bath for 3 minutes. Remove from the ice bath once the 3 minutes are up and take the necessary steps to freeze the bean sprouts.
Once blanched, drain the bean sprouts and place them in a freezer safe bag or container. Portioning out the sprouts into smaller bags can help ensure you only remove as much as you need. Refreezing damages the taste and texture of food, so once you've thawed the sprouts, its best to fully use them, so freeze individual portions. The sprouts will be usable for up to one year.
If you prefer not to blanch your bean sprouts, you can still follow the same steps to freeze them.
Frozen bean sprouts can easily be tossed directly into the pot from frozen for many recipes and you don't have to defrost them first. This works particularly well in soups or stir-fries. If you are using the frozen bean sprouts in dishes like spring rolls or salads that won't cook off the water, thaw them partially first. Put the container of frozen bean sprouts in the refrigerator about 2 hours before you need them to ensure they're partly thawed and drain the sprouts before using them.