How do we come to the conclusion about what type of "wine" this was? First, we must look at the immediate context. Notice what the governor of the feast said concerning the quality of the wine in John 2:10 "Every man at the beginning doth set forth good wine; and when men have well drunk, then that which is worse: but thou hast kept the good wine until now."Actually, it indicates exactly the opposite, that Jesus created 160 gallons of excellent, alcoholic wine, and he didn't bother to ask the Church of Christ for their permission.
This man, after having "well drunk" of the previous wine was still able to discern the difference between the wine that had formerly been served and the wine that Jesus created. If the wine were alcoholic, then he would not be able to discern the difference at all.
The first thing that alcohol impairs in the mind is the sense of judgment and after having "well drunk" of alcohol this man should not be able to discern the appearance of the person in front of him, much less the quality of two different types of drink. Yet, he can discern between the two. This indicates that the wine was of the non-alcoholic sort.
The backstory for the biblically impaired is this: Jesus is invited to a wedding* at Cana, a small town in Galilee, and the wine runs out. His mother complains to him about the fact, and Jesus at her urging performs his first miracle. He instructs the servants to bring a whole bunch of jugs of water, then tells them to dip a cup in one of them and take it to the governor**, who makes the declaration to the bridegroom that the best was truly saved for last. Then Christians say it was really grape juice.
But we're getting ahead of ourselves here. Let's break down the governor's statement*** (italicized above) and see if we can find the truth. You have the CoC's interpretation, here's mine:
"Every man" — This shows his statement to be one of general practice, not of the current party. He is informing the bridegroom of "how things are normally done," after which he will note that in this particular case, that protocol has been violated.
"at the beginning doth set forth good wine; and when the men have well drunk, that which is worse" — This proves that the wine we are dealing with in general practice is alcoholic. Alcohol, as the CoC notes, dulls the senses, including taste, and the reason the bad wine is served last is so it doesn't taste quite so bad. Grape juice would not dull anything, so to insist that this is naught but grape juice removes the very meaning from the governor’s statement****.
"But thou hast kept the good wine until now" — This is where the general practice becomes particular, thou hast. After saying that the general practice is to serve the good wine first, he informs the bridegroom that the order has been upset in this case; he has saved the best for last. There's no theological application; it's just a recognition of the high quality of the wine.
Now the governor had just been given a cup to drink, and he did not know its origin. There is no reason for him to believe that it is any different than the alcoholic wine previously served. And just as we know the difference - and draw a distinction - between wine and grape juice, so did he. But he did not say "thou hast kept the grape juice," but "the good wine," wine that is the same as the wine that had previously run out. Therefore we can conclude that the wine Jesus created was the same as normally served, i.e. alcoholic wine.
One significant problem with the CoC's interpretation is that they assume that the governor himself has been drinking - that when he says "the men have well drunk" as a general principle he is referring to himself in this specific instance - but that is in all likelihood not the case. Of all the people at the wedding, the governor was the least likely to have drunk anything because unlike the others he's not celebrating: he's working.
But the major problem is that they just can't bring themselves to believe Jesus created 160 gallons of real wine, even though the Bible tells us so.
* His own, according to "Holy Blood Holy Grail." That was a pretty funny book.
** Not an elected official but a hired hand whose job it was to organize the party. We might consider him the head caterer, wine steward, or master of ceremonies today.
*** I'll even keep it in the KJV English, just to be fair.
**** Not to mention (even as I do) the gastro-intestinal effects on a crowd, however large (the Jews had big weddings and they lasted for a long time) of 160 gallons of pure grape juice. Just drinking one glass of that gives me the trots.