How to know if water has evaporated from curry/stew? I am trying to get a curry to be thick and less watery.  At the moment I am removing solids, boiling water off and then adding solids back in later.  Unfortunately some green vegetables I put in are not practical to move and so as the water lessens they can sometimes burn without constant movement.

Is there a way to know if most water has evaporated and hence further cooking isn't neccesary?  As an example I realise when there is more water there is more boiling so when boiling has turned into small bubbles maybe that means it's enough and one doesnt need to cook further?  I can of course just take a spoon of liquid and test it seems oily rather than liquidy but just wondering if you have any other ideas?
Rather than making the whole dish then boiling off the water, you might have more success by changing the order of your steps. For example, you could:


Add all of the meat and resilient vegetables
Then reduce the sauce until you've achieved the desired consistency
Add the leafy greens right at the end 


As far as knowing when it's reached the right consistency, that can only really be achieved by stirring it and keeping an eye on it. You're also better reducing it at a simmer rather than a boil, as the higher heat can take it past the point you're looking for very quickly.