Mongo: NEVER use beaujolais for making tinto de verano. I don't care what time it is in the Twin Cities....

For my tastes, use a hearty red wine. Of course if you want to be more authentic, a tempranillo. I have found Charles Shaw (Two Buck Chuck from Trader Joes) to be very good.
The taste of the wine makes a big difference. It doesn't have to be expensive wine, but how the wine tastes absent the La Casera or whatever is what you get...

Thanks for the tip on Sierra Mist.

I have Spanish friends coming to visit in August, and have asked them to bring La Casera.
That should last about a day...

A buen provecho..