I would like to concentrate flavour by reducing the water content but I do not wish to alter the temperature of the liquid.  Is there a way to reduce the water content without boiling?  Apart from waiting days for evaporation? 
You could put the container of food into a bigger closed container also containing a strong desiccant like zeolithe or silica gel - these will probably needed to be dried in a hot oven before use, but that has nothing to do with heating or not heating the food. Make sure the desiccant is kept from contacting the food directly. The desiccant will constantly strive to dry the air in the container, whilst the food will try to do the opposite and thus lose moisture... 