An insulated beverage container comprising: a sidewall, a base connected to the sidewall, and a top forming an upper portion of the container; a thermal barrier liner applied to an interior surface of said sidewall, said thermal barrier liner comprising: a closed cell substrate layer having a plurality of cells defining voids said substrate having a surface in contact and adhered to an interior surface of the sidewall and base, characterised in that said thermal barrier liner is gas permeable such that when said container is sealed and pressurized, gas within the container permeates through said thermal barrier liner and into said voids, and when said container is open thereby exposing the interior of the container to ambient pressure, the thermal barrier liner expands in response to a drop in relative pressure, where the permeability of the thermal barrier liner is such that gas is allowed to permeate through the cell walls over a period when under pressure to reach equilibrium, but the cell walls are not so permeable that immediate deflation takes place when ambient pressure is reduced and therefore, the thermal barrier liner will maintain a full thickness for at least a period of time. a sidewall, a base connected to the sidewall, and a top forming an upper portion of the container; a thermal barrier liner applied to an interior surface of said sidewall, said thermal barrier liner comprising: a closed cell substrate layer having a plurality of cells defining voids said substrate having a surface in contact and adhered to an interior surface of the sidewall and base, characterised in that said thermal barrier liner is gas permeable such that when said container is sealed and pressurized, gas within the container permeates through said thermal barrier liner and into said voids, and when said container is open thereby exposing the interior of the container to ambient pressure, the thermal barrier liner expands in response to a drop in relative pressure, where the permeability of the thermal barrier liner is such that gas is allowed to permeate through the cell walls over a period when under pressure to reach equilibrium, but the cell walls are not so permeable that immediate deflation takes place when ambient pressure is reduced and therefore, the thermal barrier liner will maintain a full thickness for at least a period of time. a closed cell substrate layer having a plurality of cells defining voids said substrate having a surface in contact and adhered to an interior surface of the sidewall and base, characterised in that said thermal barrier liner is gas permeable such that when said container is sealed and pressurized, gas within the container permeates through said thermal barrier liner and into said voids, and when said container is open thereby exposing the interior of the container to ambient pressure, the thermal barrier liner expands in response to a drop in relative pressure, where the permeability of the thermal barrier liner is such that gas is allowed to permeate through the cell walls over a period when under pressure to reach equilibrium, but the cell walls are not so permeable that immediate deflation takes place when ambient pressure is reduced and therefore, the thermal barrier liner will maintain a full thickness for at least a period of time.