The present invention relates to a hot water supplying device for coffee machines comprising a condensation chamber having at least one output duct for supplying the hot water, a first duct having a first flow rate and arranged for injecting water or steam at a first temperature into the chamber, a second duct having a second flow rate and arranged for injecting water at a second temperature into the chamber. According to the invention, the device further comprises first interception means (21) applied to the first duct (12) and arranged for supplying a first certain amount of water on the basis of the first flow rate by intercepting or not intercepting water injection by respective first time periods of interception or not interception in a certain time interval and second interception means (31) applied to the second duct (13) and arranged for supplying a second amount of water, calculated on the basis of the second flow rate, by intercepting or not intercepting the water injection by respective second time periods of interception or not interception in the certain time interval. The invention relates also to a method for supplying hot water with a device for a coffee machine, to a computer program product loadable in the memory of a computer for realising the method according to the invention and to a coffee machine that comprises the device.