If cocktail shaker is available, add ice, frozen Riesling, lychee liqueur, vodka, mango coconut water, agave syrup and lemon juice and shake until shaker is ice cold. If no shaker, mix in a glass and stir.
Add contents of cocktail shaker to a large glass with ice.
Top with soda water to taste.
Stir and serve.
Scientist's Notes
Put the Riesling in the freezer the night before - it doesn't freeze solid, but I wouldn't recommend putting in a full bottle.Add additional coconut water with mango if there is room in the glass - this stuff is delicious and really smooths out and balances the sour from the lemon and riesling.Add frozen mango chunks if available (instead of ice).