In my experience, the Rieslings of Weingut Bründlmayer, particularly the ones from the Heiligenstein vineyard, need time to develop in the bottle and ideally should not be opened unless they are at least six years old.
The vineyards are farmed organically and all grapes are hand-harvested. Bründlmayers harvest diaries (dating back to the 2003 vintage) is a highly recommended read.