Using, Freezing, and Canning Farmer's Market Blueberries

In July and August, the farmer's markets in Chicago offer blueberries for about $5 per pint. At that price, they're an indulgence for many people, including me.

But I can buy a 5-pound box of blueberries (6 pints) for $16 ($2.70/pint) or 10 pounds for $22 ($1.83/pint). Clearly, it's a lot less expensive to buy those locally grown Michigan blueberries in bulk. But if you're throwing out those excellent blueberries because you can't use them up in time, that's not economical.

So the challenge for me is to figure out how to use up, or preserve for later, that 5- or 10-bound box of berries before they spoil.

In the refrigerator, blueberries usually last about a week. Since my typical family of four can't eat 10 pounds of blueberries that fast, I find ways to enjoy them in quantity now and preserve the rest for later.

The first plan of attack is to tell the kids they can eat as many blueberries as they want. My daughter enjoys a bowlful of blueberries with a little sugar as a snack. I eat them for for breakfast with a little Greek yogurt and honey.

In addition to eating them fresh, I usually prepare a cooked-fruit dessert based on blueberries for us to enjoy, such as the blueberry cobbler in Mark Bittman's How to Cook Everything for iPhone app. The blueberry cobbler, served with whipped cream or ice cream, is an extremely popular dessert at my house. In fact, my daughter likes it so much she begged me to buy another big box of blueberries at the farmer's market this morning.

Essentially, the recipe calls for mixing 1 to 1 1/2 quarts blueberries with a small amount of sugar, which I can omit when cooking with blueberries at their peak-season best. The topping, which is similar to but much simpler than a pie crust, is made by mixing flour, baking powder, salt, and sugar in a food processor and pulsing. The recipe then calls for adding egg and vanilla (though almond extract is an interesting substitute). I bake the cobbler while we're eating dinner, and serve it warm after the dishes are done.

The easiest way to save blueberries for later is to freeze them. To do this, I wash them thoroughly and spread them on a cookie sheet lined with a clean dish towel to air dry. When the blueberries are dry, I seal them in 1-pint plastic zippered freezer bags, such as those made by Glad or Ziploc. I then store the bags in my chest freezer. It's helpful to freeze the blueberries in 1-cup or 2-cup portions, so that you won't need to measure them later. Removing as much air as possible from the bags is important, because this prevents freezer burn.

In December (or whenever), when I want to use the blueberries, I mix the frozen berries directly into the recipe I'm making. The only time I thaw the berries is when I want to eat them for breakfast with my favorite Greek yogurt. To thaw, I place the blueberries in a microwaveable bowl and thaw for 30 seconds to 1 minute in the microwave. I then top them with the yogurt. I enjoy the temperature contrast between the warm berries and the cold yogurt, and a few almonds on top add a nice crunch.

Frozen blueberries do have a slightly different, softer, texture than fresh berries. But the flavor is much better than out-of-season fresh fruit flown in from far-away places and very similar to that I enjoy in July.

If you don't have freezer space, canning is an option. If you're canning, it's important to closely follow standardized recipes and directions, such as those in the Ball Blue Book Guide to Preserving or from the USDA. Detailed directions are also available at pickyourown.org. When you're canning, do not improvise. Find and follow detailed directions from a reliable source, such as those listed above.

The basic process of canning blueberries begins with thoroughly cleaning the jars, bands, and lids in the dishwasher. As for other canning projects, the lids are preheated in hot, but not boiling water. While you're preparing the jars, fill and begin heating the large quantity of water you'll be using in your canner.

Wash the fruit and pick out any unripened, soft, or damaged blueberries. Pack the blueberries into your canning jars and cover them with a sugar syrup. Seal the jars and process them in a boiling water bath according to directions from Ball, the USDA, or another reliable source.