You Should Never Microwave Red Pasta Sauce. Here's Why

Everyone can appreciate the convenience of nuking food when you're tired or short on time, but there are some foods that just don't belong in the microwave. Red pasta sauces absolutely fall into this category — with plenty of evidence. You've probably had red sauce explode in the microwave before and splatter everywhere, even if it was from something like a meatball sub or leftover pasta. No one wants to be bothered with cleaning up such a mess.

Essentially, tomato pasta sauce is too thick to heat up using the microwave. The heavy consistency makes it difficult for the sauce to create escape routes for steam that builds up beneath the surface. That's why it pops and splatters all over the place — the pressure increases until it overcomes the weight of the sauce and sends it flying (via Eat This, Not That!).

The exact reason why red tomato-based pasta sauce spews all over the place when heated quickly primarily has to do with the ingredients it is made of and their physical properties.

Some liquids like water can be heated in the microwave because the molecules are more even, which in turn allows them to move around more easily when heated. Tomato sauce, on the other hand, has a lot more substance to it. It includes water, but it also has additional ingredients like fructose, glucose, fiber, proteins, and ash. It might also have different oils, acids, and spices if it was bought from the store. All of these additional components create a gelatinous liquid that heat then has to move through when it is in the microwave (via HuffPost).

All of these components create a higher viscosity, or thickness, within the sauce. So, the water molecules, which have a low viscosity, separate from the other ingredients when the sauce is heated up more quickly. This is how the water gets trapped and causes pressure to build.

To avoid splattering, you will need to stir it consistently, which isn't the easiest thing to do in a microwave. That's why it is really better to heat it up over the stove — your sauce will be more evenly heated and there won't be a mess to clean off the microwave walls afterward.