Old pasta but I feel compelled to answer anyway
Despite my flag I'm a second-generation Italian, and Italian at heart.
I follow a strict Mediterranean diet not by desire to be healthy but by culture, I speak Italian daily and despise commercial pizzas. It's just how I've been raised.
My own ancestors are born in Italy in poor families and had to flee the fascists because they were communists. For these reasons, they have been very careful to not waste anything, in particular cooking byproducts. This includes pasta water.
Like most poor families here in Southern Italy, or so I've been told, they would thus keep their pasta water and only add a little bit of water every time to dilute it (so no steaming nonsense). They would also give part of the pasta water to kids leaving home to get married so that they can continue cooking with the family's pasta water. My grandparents and parents have kept this tradition alive and I received about a liter of our pasta water to cook with when I went to the big city to study. I keep it refrigerated and so far the taste hasn't changed too much.