Published September 1, 2007.
Simply substituting pears for apples in this classic American dessert is a recipe for disaster.
Pears react quite differently from apples when baked in a crisp. They exude so much moisture that a traditional crisp topping will sink into the filling and won't get crunchy. Pear varieties, unlike many kinds of apples, are not interchangeable.
We wanted to create a classic crisp—one with tender fruit and a crunchy, sweet topping to provide textural contrast—using pears rather than the more traditional apples.
A little science is necessary to understand why pears react to baking so differently from apples. While pears and apples contain almost the same amount of moisture, they have cell walls of very different strengths. When heated, pear cell walls break down much faster, exuding a lot more juice and making baked pears mushy. We found that different pear types react differently from each other; the strongest were ripe yet firm Bartlett pears. To compensate for all the liquid, we added a slurry of cornstarch mixed with lemon juice. Even with the thickened juice, our standard fruit crisp topping washed down into the filling. We needed a sturdier topping. A streusel-type topping, made by incorporating melted butter into the flour, kept its crunchiness; the melted butter helped bind the flour to the other topping ingredients.list of recipes