Blueberries 101

• Wild blueberries are native to North America, growing profusely in meadows and scrubby, rocky terrain that other plants find challenging. The small berries grow low to the ground in tight clusters, where they can be hand-harvested individually or with large, specialized rakes. Cultivated high-bush blueberries are grown like other garden plants, in orderly rows that are more easily harvested. The small wild blueberries have a more intense flavor, but both wild and high-bush berries are highly nutritious. They're widely touted as a super food within the health-foods industry because they're high in anti-oxidants, such as the anthocyanin that gives them their color.

Frozen Blueberries

• Freezing foods has an impact on their texture and appearance, because as the moisture in their cells freezes, it expands and ruptures the cell walls. That's why most frozen foods release moisture as they thaw. Wild blueberries freeze better than high-bush cultivated blueberries, because they contain less water. That means less expansion, so the skins are better able to contain the berry's flesh and juice without bursting. Either type of berry will release large quantities of juice when thawed.

Baking from Frozen

• If you thaw the berries before you use them, they'll still retain their flavor and nutrition. However, their juice will quickly spread throughout your batter once you mix them in. If your goal is to have a purple batter, that's great. However, if you'd rather have a white cake or muffin with distinct blueberries dotted through it, you'll need to add them while frozen. When the berries thaw in the heat of the oven, their color and flavor will be confined to their immediate area. Baking soda can give blueberries an odd greenish tint, so use baking powder instead, if possible.

A Few Tips

• Mix your batter completely before adding frozen blueberries, and then fold them in at the last minute. That minimizes the amount of juice you'll spread through the batter in vivid purple streaks. If your recipe is heavy in berries, the berries might cause part of the batter to freeze, so add them a few at a time as you stir. Tossing the frozen berries with a light dusting of flour can help them mix in more easily. In wet doughs, it can also help prevent them from sinking to the bottom of the cake or cupcakes.