1) Single grape variety Riesling (100 %) 2) 100 % of the grapes must come from Germany (written confirmation from producer to be presented upon purchase) 3) Min. 12 g/l, max. 25 g/l sugar 4) Charmat or traditional method (does not need to appear on label) 5) Only one offer per producer. If more than one offer is submitted by the same producer, only the lowest priced offer will be assessed for purchase, regardless of wholesaler 6) "Guarantee of supply" must accompany the offer