A hydration system includes opposing flexible walls forming a bladder having a sealable compartment for containing a liquid. The system includes a drinking tube having a first end with a valve and a second end. A first port is configured to receive pressurizing gasses into the compartment. A baffle connects the opposing walls within the compartment. The baffle is configured to oppose expansion of the bladder as the pressurizing gasses are introduced into the compartment. A second port is configured to couple to the second end of the drinking tube to provide fluid communication between the compartment and the drinking tube. A third port allows the liquid to be supplied into the compartment. Activation of the valve unseals the compartment and allows the liquid to be expelled from the compartment via the second port and the drinking tube as a result of a pressurization of the compartment by the pressurizing gasses.