I've been reading Gray's Western Inner Workings and a couple of things he's written relate to blood and sacrifice.

"There has been so much talk of "sacrifice," yet what does the word actually mean? Strictly speaking, it comes from two Latin words: sacra--holy, and faerce--to make. The entire meaning; therefore is to make holy. Just that. All the implications of renunciation, blood-offerings, self-denial, and so forth, are accretions and attachments over the centuries of customs so described. Why not accept a perfectly good word in terms of its original value, and grant that when we talk about "self-sacrifice" what we mean at rock-bottom is "making ourselves holy." That is to say, devoting our energies towards changing our characters and self-structures into a more "Godworthy" state."

"In a sense we are micro-organisms in the "Divine Body of God," but what sort? [snip] Hence, the reason for doing certain exercises with circles of consciousness around ourselves. They are to ensure the correct circulation of our inner energies so that we become healthy and useful spiritual organisms in the Great Body of God. That was the secret message which Jesus was imparting to his chosen disciples with the Body-Blood sacrament. He was symbologically telling them that they should strive to become as Blood within the Body of the Living God which is created Cosmos. That is the Sangreal or "Holy Grail"--becoming the Blood of God, the legendary Ichor of Immortality."

I think that red wine would be considered an appropriate substitute, as would grape juice. :)