And I said "assume", not "know". :) Some Protestant churches use wine, not grape juice, which has historically had a "temperance" association. Welchade grape juice was, if I recall the story correctly, invented by a Dr. Welch who wanted a "temperance" communion drink.
Interesting
But wine or grape juice, what does it matter, both represent the shed blood of Christ unless your Catholic, then it really is the shed blood
The bottom line is..."do this in remembrance of me"
1 Cor.11:25