The invention relates to an apparatus for storing a liquid, comprising at least two series-connected storage cells (3), with hot liquid being able to be supplied to, or removed from, a first storage cell (3) via a first central line (35) and with cold liquid being able to be supplied to, or removed from, a final storage cell of the series-connected storage cells (3) via a second central line (33), and with the temperature of the liquid in the series-connected storage cells (3) decreasing in each case from the first storage cell (3) to the final storage cell (3), and the individual storage cells (3) being connected to one another in each case via a connection (5; 7) from the lower region (11) of the warmer storage cell (3) to the upper region (15) of the colder storage cell (3), and with at least one storage cell (3) being closed by a cover (27) and therefore a gas space (25) being formed between the liquid in the storage cell (3) and the cover (27), wherein a gas line (29) branches off from at least one gas space (25) and enters into the liquid of a colder storage cell (3) or into the liquid in the connection (5; 7) of two adjacent storage cells (3), at least one of the adjacent storage cells (3) having a lower temperature than the temperature of the storage cell (3), from the gas space (25) of which the gas line (29) branches off.