I realize that the Bible does not speak to this issue.
Color is a matter of indifference.
Some Lutherans have tended to use white wines to lessen the visual imagery, while others have used red wines in order to heighten the sensory stimulation. At one point in Lutheran history, Lutherans tended to use white wine. So Lutherans have in some places used white wine to show that they were free in this matter and that the Word and promise of Christ alone make it the blood of Christ, not whether it's white or red. Whatever a congregation is used to receiving is probably what should be continued to be offered. Making a sudden change can be rather problematic.