Stoichiometric water level is very low. In fact, the stoichiometric water to cement ratio is from 0.2 to 0.25. Using water content less than this level will not be sufficient for the hydration process to take place.
A lower ratio leads to higher strength and durability, but may make the mix difficult to work with and form. Workability can be resolved with the use of plasticizers or super-plasticizers.