Combine 1 cup wine, sugar, and sachet in a small saucepan; bring to a simmer. Cook 5 minutes. Remove from heat; cool. Discard sachet. Pour mixture into a pitcher; add remaining 3 cups wine. Chill thoroughly. Add juice, strawberries, orange slices, and club soda.
Served with seafood paella at a family gathering. It was deemed the best sangria ever and the recipe quickly disappeared. The mulled spiced base deepened the flavors. Adding the frozen strawberries just before serving really helped keep the wine chilled. To kick up the flavor I used lemon - lime sparkling water and added a splash of Triple Sec and Lemon Vodka. Can't wait for a chance to make this again.