Im a secret chef amd spanish food lover.
Legend has it that when a Valencian wants to successfully replicate the recipe of his paella, outside the Community, he carries a bottle of tap water from Valencia, since he tends to defend himself that the hardness of the water in Valencia favors the point and ease of rice. However, there is little truth in this statement.
It is true that trying to replicate the way of cooking a paella, without further adaptation, in any other location outside the Community, is to condemn it to failure. But the reason for this is not that you can only cook with the Valencia water, but that it will be necessary to adapt the cooking time to the conditions of the new location.
The Holy Trinity of the point of rice in a good paella, is a perfect combination between the amount of water, the amount of rice and the cooking time of each variety of rice taking into account that, at the end of cooking, the rice should be left completely dry What happens is that there are factors such as the height above sea level or the hardness of the water that significantly influence the cooking times. In fact, these factors, especially the height above sea level and, therefore, the pressure, influence the boiling temperature of the water. That is, the higher the height above sea level, the lower the atmospheric pressure, and therefore, the boiling point of the water will decrease accordingly, which will require a longer cooking time, and a proportion of water and rice adapted to that variation, to leave the grain to the point.
The paella masters tend to have the point of the rice, and therefore, the amount of broth and cooking time necessary, very measured in their land. However, in other locations, it will be necessary to resort to the method of error, or physics, to reach the same point of rice. Conclusion; It is not true that a good paella should be cooked with Valencia water. It will simply be necessary to adapt the cooking times and the ratio of water and rice, to the new conditions.
I do not know which is the best of all the paellas, if the Valencian or one that probe in santorini