How does gravy boil?

Gravy doesn't actually "boil" in the traditional sense. While you might see bubbles forming on the surface, this isn't true boiling. Here's why:

* Gravy is a thickened liquid: The starch in gravy (from flour or cornstarch) creates a thick consistency. This prevents the gravy from reaching a full boil, where the water molecules are moving rapidly enough to create steam bubbles.

* Gravy is usually cooked at a lower temperature: To prevent scorching and ensure a smooth texture, gravy is typically simmered or gently heated, rather than brought to a full boil.

* Bubbles are due to trapped air: The bubbles you see are likely from trapped air that's released as the gravy heats up.

So, instead of boiling, gravy is typically "simmered" or "reduced":

* Simmering: Keeping the gravy at a gentle simmer (a low, steady bubble) allows the flavors to meld and the sauce to thicken slightly.

* Reducing: Heating the gravy for longer periods can evaporate some of the liquid, making it thicker and more concentrated.

In short: While you might see bubbles in your gravy, it's not truly boiling. It's usually simmered or reduced to achieve the desired consistency and flavor.