Exemplary embodiments of a high temperature aging cell provide a metal-to-metal fluid seal, and generally include a central tension post containing a flange having an inclined surface; and a seal ring concentrically arranged thereon, its outer circumference positioned at least partly intermediate the flange and the cell interior surface. In various embodiments, a thrust ring retains the seal ring; a thrust washer engages the thrust ring; a tension ring is attached to the tension post for biasing the thrust ring toward the flange; and an outer cap retains various components in relation to the aging cell. A pressure control device allows for pressure elevation.Exemplary embodiments of a sample aging method generally include aging a liquid sample by sealing the sample in the cell via biasing of the seal ring into sealing engagement with an interior surface of the cell. Subsequent sample treatment may involve elevating its temperature and / or pressure.