Why do you salt pasta water?

Salt is added to pasta water primarily to season the pasta directly as it cooks. Aside from flavor considerations, though, adding salt to pasta water also slightly raises its boiling point in a process known as boiling point elevation. Although this change is minimal, it can help pasta cook more evenly, which is particularly useful when preparing larger batches.

Cooking pasta in salted water also has the added benefit of helping the pasta maintain its structure and firmness, or al dente texture, which prevents it from becoming too soft.