Is It Safe to Freeze Yogurt?
If you have too much yogurt, you might be tempted to freeze it so that it lasts longer. After all, the dairy product is nutrient-rich and so versatile, so tossing away the extras would be shame. Frozen yogurt can be used in smoothies, as an ingredient in baking, and as a "froyo" style dessert. But is it safe to freeze your yogurt? Our experts say yes—so long as you do it correctly, that is. Simply tossing a container of yogurt into the freezer isn't optimal. There are safer, more effective ways to prolong the life of the dairy product.
Yogurt is milk that has been transformed thanks to heat and active yogurt cultures including Lactobacillus Acidophilus. If you freeze natural yogurt that has no added ingredients, when it defrosts the texture will not be creamy. According to Liam Callahan, co-owner and cheesemaker of Bellwether Farms, makers of award-winning sheep and cow milk yogurts, "Yogurt's delicate, smooth, and creamy texture is what has made it a favorite 'superfood' for almost 8,000 years. Unfortunately, freezing destroys this and results in graininess due to the forming and thawing of the ice crystals."
There are many different kinds of yogurts and they each have different ingredients and compositions, which will yield a different texture when frozen. Many commercially available yogurts have added cornstarch, pectin, gelatin, or food starch to prevent separating and to maintain a smooth and creamy texture. Those added ingredients can help mitigate the effects of freezing. Callahan reports that some yogurts will be slightly less damaged with freezing including those that have been artificially strained to have higher solids such as Greek yogurt, but that even those may show damage from the process.
How to Freeze Yogurt for Smoothies and Baking
The best way to freeze yogurt is dependent on how you plan to use it. If you are going to use it in baking or in a smoothie, the change in texture when it defrosts is not a problem. To make it easier to manage, you may want to freeze it in ice cube trays so you don't end up with a large, unwieldy block that takes a long time to defrost or blend in a blender.
Making a Frozen Yogurt Dessert
If you want to make froyo style frozen yogurt for dessert, you'll need to adjust both the ingredients and the freezing technique. Nicole Weston, author of Perfectly Creamy Frozen Yogurt ($9.90, amazon.com) explains, "One reason why 'frozen yogurt' is different from 'yogurt that has been frozen' is that it contains more added ingredients. Homemade frozen yogurts, including mine, add sweeteners that act as stabilizers to give the desserts a creamier texture when scooped, as well as to enhance the flavor of the finished frozen yogurt. Store-bought frozen yogurts typically add both sweeteners and extra stabilizers, both of which prevent the yogurt base from breaking and maintain their creamy texture after freezing." A couple of the ways Weston stabilizes yogurt for frozen desserts is by adding sugar and using a meringue mixture of beaten egg whites and sugar. She also notes that higher fat yogurt and strained yogurt yield better results.
Callahan recommends using sheep's milk yogurt for froyo. "Sheep's milk being naturally higher in protein and fat makes a wonderful frozen yogurt for any gelato lover," he says. "I use 16 oz. plain sheep yogurt, 8 oz. blackberry or strawberry preserves (tart fruit works best), and 4 oz. granulated sugar. You can eliminate the added sugar for a [tarter] version." The key to Callahan's recipe is the use of a canister "frozen bowl" style home ice cream maker. Other methods include a hand crank ice cream maker or a compressor ice cream maker. If you want to make frozen yogurt without an ice cream maker, Weston suggests freezing your yogurt mixture in a baking dish and stirring every 15 minutes or so to prevent the formation of ice crystals.