How to Freeze Blueberries

If you've ever dumped a bunch of fruit, especially wet or cut fruit, into a zip-top bag and tossed it in the freezer, you know the heartbreak of pulling it out later to find a giant, singular block of ice. You practically need an ice pick to break any pieces of fruit off. This is because the liquid from the fruit freezes into ice and fuses the fruit together.

But when you buy fruit in bags at the store, it's not in one huge ice chunk, and the pieces are all loose. This is because, at industrial frozen fruit processing plants, blueberries and other fruit are frozen using a system called IQF. This stands for "individually quickly frozen" and is the standard for freezing fruit and vegetables. Thankfully, you can mimic this process easily at home. 

How to Freeze Blueberries

The basic process of IQF consists of fruit being spread out in one layer so that no two individual pieces are touching and frozen, then packed into bags once it's already rock hard. You can easily IQF blueberries and other fruit at home by employing the same method. 

You can wash your berries first, but make sure they're absolutely 100% dry before starting the freezing process. If they're wet, the water on the outside will form ice and can ultimately freeze the berries together, even if they're spread out, and waterlog your berries. 

Spread your fresh, dry blueberries in a single layer on a sheet tray lined with a silicone baking mat or parchment paper, and put the whole sheet tray in the freezer. Once the blueberries are completely frozen (freeze for at least three hours, but overnight is best) package them into freezer-friendly containers or zip-top bags. Label and date the containers and store them in the freezer.

How Long Do Blueberries Last in the Freezer?

Blueberries are known for being a delicate fruit, and we all know that once one goes bad, the entire container isn't far behind. Freezing them can greatly increase their longevity and buy you lots of time before they spoil. However, they're still perishable and don't have an infinite shelf life in the freezer. If frozen correctly and sealed properly, clean blueberries should last in the freezer for up to a year, but they're best before the six-month mark. 

Before you freeze your berries, always pick through them and make sure none of them are moldy or rotten, because if you freeze just one that's bad, it can contaminate the whole bunch, and the batch will need to be thrown away regardless of how long they've been frozen.

How to Thaw Blueberries

Blueberries tend to lose a lot of their structure after they've been frozen. Ice crystals form inside the berry, which are sharp and cause the berry to expand. When they defrost, the berries tend to deflate a bit and release a lot of their juice. Because of this, frozen blueberries are best suited to uses like muffins and pancakes where you want that classic blueberry flavor but aren't as concerned with the plump snap of fresh berries. 

To defrost the blueberries before use, the best way is to pour out the amount you need into a bowl or container, cover, and thaw slowly in the fridge overnight. You can drain off the juice if you don't want it, but some recipes will benefit from replacing a bit of the liquid called for with that delicious blueberry juice. If you need them quickly, keep them tightly sealed in the package they're frozen in and place them in a bowl in the sink. Run a steady but thin stream of cold water from the faucet over the bag or container, and depending on the size of the bag, they should be ready to use in less than an hour.