Why are solid shortenings not the best choice for frying doughnuts?

Solid shortenings are not the best choice for frying doughnuts primarily because they can create an unpleasant texture in the finished product. When frying doughnuts, the ideal fat should provide a light and airy texture, which is more effectively achieved with liquid fats or oils that have high smoke points and can circulate evenly around the doughnut as it cooks.

Solid shortenings, due to their consistency, may not melt completely or evenly, leading to greasy or dense results rather than the desirable fluffy and crispy texture. This can also contribute to uneven cooking, where parts of the doughnut may become overcooked while others remain underdone.

In contrast, oils that are specifically designed for frying will heat evenly, contribute to a better mouthfeel, and prevent the doughnuts from absorbing too much grease, resulting in a superior final product.