This is what Dr. Lewis wonderfully explains for us in his brief article on the miracle at the wedding in Cana.
However, Jesus really did change the water into wine, thus revealing his glory. At a molecular level, the water, basically hydrogen and oxygen, was changed into wine that contains sugars, yeast, and water, which contain carbon and nitrogen along with oxygen and hydrogen. Thus, by changing water into wine Jesus demonstrated his authority over even the atomic structure of atoms by commanding oxygen and hydrogen atoms to disassemble and reform into other atoms of different configurations.
The amount of energy it would take to perform this atomic deconstruction and reconstruction is staggering. This intermolecular energy being released is the source of the explosive energy from an atomic bomb. However, since Jesus caused the wine atoms to come back together, he would have to put this astronomical amount of energy into the atoms in order to have them reconstruct. To do so without any visible energy transformation of the liquid (John does not say anything about people noticing the transformation) indicates a mastery of natural law far beyond our current comprehension. And he accomplished it with no physical exertion.
With this single act Jesus proves that the basic forces in nature are at his command and control. Certainly one who controls the basic forces in nature controls all of nature, thus Jesus truly revealed his complete control of the physical universe through this act.
“And the Word became flesh and dwelt among us, and we have seen his glory, glory as of the Father, full of grace and truth” (John 1:14).