Risotto occasionally never cooks through?

I've also found that the kind of rice has a big impact on cooking time- the carnaroli rice that I can get at our Italian specialty store takes about twice as long as the arborio rice.

Technically, the ratio is meant to be 3:1, but I always wind up closer to 5:1. Make sure that the broth you add is very warm (you can slow/halt the rice cooking process by adding cold broth). I stand and stir mine with a wooden spoon almost the whole time, usually it winds up being at least 1/2 hour or 45 minutes. I find that stirring releases the outer starch coating of the rice and creates the most creamy texture. Also, be sure to let the risotto rest off heat for 5-10 minutes at the end, that seems to help bring flavors and texture together.

I always make sure that when I ladle the broth, there is a 1/2 inch of liquid above the rice. Make sure you don't over mix, and let the broth be absorbed at medium heat. It may take 4 or 5 reductions to make it right.

I use Sushi Short grain rice whenever I make risotto. Sometimes it can take awhile to cook, but as long as I use medium high heat and constantly stir and a gentle beat, it works alright. Maybe make sure your heat is at temperature.

Sometimes if the rice is "older" it doesn't lose that crunch. If you've had your arborio rice in the pantry for a while, you might need to replace it.

There really isn't a set amount of stock to rice. I learned from a native Italian, and she had/has me always bring a big pot of stock to the simmer. Whatever is left over can be put away, frozen, whatever you want. You just have to go until the rice won't absorb any more liquid.