A machine for preparing coffee beverages comprises an infusion unit comprising an infusion chamber suitable to contain a quantity of coffee powder to be subjected to infusion, a grinding unit to grind coffee beans and obtain coffee powder, a water tank connected to the grinding unit, means for feeding and heating the water, and a dispensing unit fluidically connected to the infusion unit and configured to dispense the beverage prepared into a receptacle. The invention also concerns a method to regulate a machine for preparing coffee beverages.