Cut lemons and oranges into slices and add them to the pitcher.
Add the red Spanish wine, sugar, Spanish brandy, and Cointreau to the pitcher and mix well.
Allow the fruit to steep in the mixture for several hours before serving. If possible, let it sit overnight so that the flavors of the individual ingredients have had time to fully come together.
A few hours before serving the sangria, place the pitcher in your refrigerator to chill the beverage.
Remove from the refrigerator and add the club soda and ice immediately before serving.
Don't be afraid to experiment with other wines and fruits to create a signature sangria. White wines such as Rioja, Pinot Grigio, or a Riesling are great for making Sangria Blanca and would pair well with other fruits and berries outside of the citrus family.