Weinschorle is one of my favourite summertime drinks yet few people in The Netherlands are familiar with Weinschorle, and many react with horror: adding water to wine? Sacrilège!

They don't get it. Man muss nur wissen, wie man seine Weinschorle trinkt. 

The wine
The first rule is to use a good quality wine. When mixed with water, a bad wine will still taste bad. The strongest aromas will prevail. A Riesling is the classic wine for a Weinschorle, but not the only suitable wine.

The water
The next factor is the right water for the right wine. Never use mineral water with too much taste because the minerals will overpower the wine. A Riesling has much acidity by itself, therefor carbonated water with too much carbon dioxide will accentuate the acidity. For a Riesling it is therefore best to use a medium carbonated water. Grauburgunder, Chardonnay or Silvaner can take water with higher carbon dioxide content. 

You have to experiment. I like to mix Riesling with Gerolsteiner Medium, if I can find it in The Netherlands. You can even make a Weinschorle with still water.

The ratio
This part might be controversial. In most parts of Germany the ratio wine to water is fifty-fifty. Now this is fine for a very hot summer day and I am not arguing against it. In the Pfalz, where they take their Weinschorle very, very serious, the ratio is different and somewhere between one quarter and one-third water to three quarters and two-thirds wine. Since the classic Weinschorle glass in the Pfalz is the 0,5 liter Dubbeglas I was puzzled. The alcohol content for one Pfalzer Weinschorle can be as much as two 0,2 liter wine glasses. But apparently the Dubbeglas was passed around and everybody would take one sip.

Red wine or rosé
You can also make a Weinschorle with red wine. The carbon dioxide in the water not only enhances the acidity but also the tannins. Use a red wine low in tannins like a Spätburgunder, Dornfelder, Merlot or Trollinger. A rosé or Rotling is the perfect wine for a Weinschorle. 

Source: Weinschorle hat ihren schlechten Ruf völlig zu Unrecht