I have heard one should use a lot of water when cooking pasta; how much water should I use?
I have found that enough so that upon evaporation, you don't run out is the correct amount. But then again, using too much takes longer to boil. I try to find an optimum based on these two factors.
My rule of thumb is 4 qt. of water per 1 lb. of pasta. This comes from a Cooks Illustrated article (I think from around '00) that suggested that this was the best way to keep pasta from sticking to itself.
I prefer to use more water than is likely necessary, simply because when you add the pasta to the water, the temperature will drop some. The less water you have, the lower it will drop/the faster it will take to bring it back to a boil. Edit: This very likely may be a disproven myth, please read comment below.
Unfortunately I eyeball it based off how much pasta I have, so I can't give you an exact ratio. But I would err on the side of too much. Edit: I just eyeballed and then measured a pot, it looks like I use about 5 quarts of water for a lb of pasta. I still recommend erring on the side of too much, but now only because you don't want to lose too much to evaporation and end up running low on water halfway through cooking. Just enough to cover the pasta a little bit seems to work fine at our house.
This question was answered to some extent in another Pasta cooking question by Roux. This answer, which is basically just a link to a series of experiments by an MIT grad / Chef, dispels a number of myths about cooking pasta. For instance:
Some really interesting stuff in the article that debunks quite a lot of kitchen lore about cooking pasta. I have tried this at home with great success.
So in answer to your specific question:
That is nonsense. The more water per pasta ratio will result in less recovery time, which is more desirable. It's simple. Boil a gallon of water and add an ounce of pasta. The water will not stop boiling. Boil it again and ad a pound of pasta. The water will take time to recover. For dried pasta, every manufacturer recommends rapidly boiling water. Aldente reqires high heat to cook the outside of the pasta, leaving the inside slightly undercooked. This is were the "snap" comes from.
Cooking pasta requires the water-to-pasta ratio shown in the table