Grosset Polish Hill Riesling is produced from the eight-hectare estate-owned Polish Hill Vineyard (ACO certified organic and biodynamic) in the Clare Valley. The gently sloping site, selected and planted by Grosset in 1996, is comprised of silt and shallow shales over a thin crust of clay and gravel. This overlays a bed of blue slate, estimated to be around 500-million-years old.
This ‘hard rock’ site was originally part of a larger estate but was considered to be of limited agricultural value and so was sold off. The vines here struggle to draw nutrients from the soil, so the bunches and berries are small, and the fruit flavours lingering. Indeed, this vineyard exemplifies how old-rock profiles can contribute to a wine’s character.
A major challenge of this site, which is perhaps the most extreme example in the subregion famous for variable geology, is the variability in vigour from one vine to the next. This demands hand-tending skill – varied to suit each vine – to achieve balanced vine growth and even fruit ripening.
Relatively close-planted, there are three clones of riesling (two German and one rare local clone). Its rocky profile is doubly challenging, resulting in more intense labour input and lower yields – an average of just two bottles of wine per vine.