Pay 3 Get 4. This set contains 4 pieces Extreme Riesling. The diamond-shaped machine-made Riesling glass of the eye-catching glass collection Extreme is focused on New World Wines. The shape of the glass best supports floral white wines – aroma and taste are dominated by fermented grape juice and the flavor of yeast. The Extreme glasses derive their name from their extreme contours. All RIEDEL glasses are dishwasher safe.