Why does water evaporate from curry better when you off the gas then heat again

There's no particular reason you couldn't prepare a stock with something other than water, but it's the equivalent of buying a ream of heavy pink paper, rather than plain white photocopy paper. If that's the effect you really want, great. The thing is, stock is meant to be as boring as plain white photocopy paper -- it is a foundation for other things, versatile and effective, subtly enhancing without overwhelming the dish. For your beer idea, for example, I would cook down a couple bottles and add some stock to it. That way, the rest of my batch of stock would be useful for other recipes that don't use beer.

Note that stock may be boring but shouldn't be flavorless; stock still should taste good. If your stock was flavorless, try upping the amount of meat, veggies, and herbs compared to bones. Also, bear in mind that stock should not contain salt (you will likely reduce the stock at some point). The lack of salt, however, will deaden the flavor. When you are ready to use the stock, be sure to add a pinch of salt.

If Tomatoes aren't cooking quickly. What i do is heat enough oil to high temp and add finely chopped tomatoes and let them cook in oil. Do not add water. Tomatoes have natural water in it. keep stirring till they break down and dissolve. Let all of its water nearly evaporate. Once oil starts separating from tomatoes that means its done.