Smaragd is a designation of ripeness for dry wines used exclusively by members of the Vinea Wachau. The wines must have minimum alcohol of 12.5%. The grapes are hand-harvested, typically in October and November, and are sent directly to press where they spontaneously ferment in stainless-steel tanks.

Zwerithaler is a sub-site of Buschenberg and sits to the east of Weißenkirchen. The name Zwerithaler, meaning "nestled between the valleys," is a near monopole of Weingut Prager. It has a complex soil of paragneiss with alternating layers of dark and calcareous rock.  Zwerithaler Kammergut is a 0.34-hectare parcel planted before WWI. The wine from these ungrafted, 100-year-old vines was bottled separately by Prager for the first time in 2015.