Ries is noted for applying classical sculptural reduction to cold optical crystal rather than using traditional hot techniques such as blowing or molding.

He refined his skills during the height of American studio glass movement under the mentorship of its principal founder, Harvey Littleton.

Ries also established a private studio in Tunkhannock, Pennsylvania, which he has used to explore concepts in glass and occasionally other media including wood and paint.

Ries's primary medium is clear lead crystal, a glass with an unusually high refractive index, extreme light transmission in the visual range, and outstanding homogeneity.

Ries begins with large blocks of optical glass and reduces them to the desired form by cutting, carving, grinding, and polishing them.

One of Ries's most famous works, the 1,100 pounds (500 kilograms) Sunflower IV, took four months to anneal and required a further 1,800 estimated hours to carve.

Contemporary critics have noted Ries's unique ability to exploit glass's optical properties for artistic expression.

James Yood, professor of contemporary art theory and criticism at Northwestern University, called Ries's work “an art of such suggestiveness and finesse, of ceaseless transition and surprise that it constitutes one of the most intriguing exercises in the poetics of optics anywhere in contemporary art.”[11] Ries himself characterizes his work as a “vessel for light,” noting that “all that we know about the universe, the composition of the stars, and the distances within the universe is studied through light...It is the one medium that gathers, focuses, amplifies, transmits, filters, diffuses and reflects it.