Abstract: A method of making a double-walled vacuum container includes the steps of forming a double-walled container from gas-impermeable, radiation transmissive material with spaced-apart inner and outer walls that enclose an interior volume with a lacuna between the inner and outer walls; coating surfaces of the container walls that face the lacuna with a reflective coating; positioning the container in proximity to a source of coherent radiant energy; and removing selected portions of the reflective coating by impinging coherent radiant energy on portions of the reflective coating selected for removal.

Abstract: A storage flask for maintaining a brewed beverage in a selected elevated temperature state includes a pair of spaced substantially gas-impermable inner and outer walls with interior facing wall surfaces in spaced relationship to one another that enclose an interior lacuna therebetween with subatmospheric pressure conditions in the lacuna. The inner wall defines an inner containment volume for storing the brewed beverage. A first portion of the spaced inner and outer walls is infrared radiation-absorbing in character and forms a heat input portal so that heat incident on the outer wall is radiatively transmitted by the portal to the containment volume for maintaining the brewed beverage in the containment volume at a temperature greater than ambient; and a second portion of the inner and outer walls is infrared radiation reflective in character and bounds the first portion.