What's True Culinary experts say preheating ovens to temperatures outlined in recipes will help guarantee the dishes turn out like their creators envisioned. What's False Skipping the preheating step may not necessarily ruin some dishes — depending on what they are, the techniques used for assembling them, and oven types. Origin In November and December 2020, posts on social media surfaced regarding the necessity of preheating ovens. Online food bloggers for years swore the step necessary to ensure culinary success, while less patient people reported forgoing the step without much lost. Below, we addressed the underlying claim of the latter posts: waiting for ovens to fully warm up to a specific temperature — or preheat — is not a necessary step, even for recipes that explicitly include the requirement.