"This brings us to a statement over which multitudes have stumbled: concerning the blood flowing out of the winepress, even unto the horse bridles, for a distance of a thousand and six hundred furlongs. This is a scary scene for those who think this is literal or that there is a literal battle of Armageddon with hundreds of thousands of soldiers, horses, and rivers of blood flowing. Men who persist in teaching that this is a literal scene should stop to consider all the facts involved in what the prophet saw. We have a description of the harvest and vintage of the earth. No man can maintain other than that these are a figurative harvest and vintage of the earth, to be followed by the great spiritual feast of Tabernacles. Even the so-called “literalists” are not literal in this respect, for they don’t view it as a natural harvest or vintage of grain and grapes! We also find the reapers with sickles, gathering the clusters of the vine, whose grapes are fully ripe. No man can maintain that these are literal sickles, literal vines, and literal grapes! The grapes were cast into the winepress of the passion of God. However one interprets the scene, that winepress is not a literal winepress. No sane man can dispute these statements. Neither is the treading a literal treading. And yet in view of all these facts unspiritual men maintain that the balance of the prophecy has to be fulfilled literally, they doggedly persist in alleging, against all reason, that the predictions concerning blood, and horses, and bridles, and the sixteen hundred furlongs, must be fulfilled literally! In their folly they refuse to believe that this scripture is fulfilled unless it can be shown that such an impossible event has actually been seen by man!"
Much more on blood and wine in the link:
"Those who look for the literal fulfillment of this portion of the prophetic vision are most certainly in error. That a river or lake of actual blood, two hundred miles in extent, deep as the bridle of a horse, all coming from a literal winepress in which grapes are being trodden by human feet is incompatible with either natural law or spiritual sense, and not in accord with the purpose and teaching of this part of the vision. The record tells us in the first verse of the first chapter that the things that were to come to pass were “signified,” or communicated in sign language or symbols."
"Now in vision John sees the process of fruitage begin. Clusters of grapes from the vine are gathered. In the eastern countries even today, and more so in ancient times, where grapes are grown, the rich clusters are thrown into a huge winepress outside the city walls. There the juice is released by the men who trample the grapes in bare feet to the rhythm of the vintage songs (see Psalm 81) sung by the women. Each winepress has a spout, and the grape juice, or life of the fruitage, flows out into jars, as a stream of water might flow. In verse twenty we read that as a result of the harvest and its exceeding bountifulness, the mighty stream of the life of the fruitage is as blood. In other words, the life is released from the clusters in the same way the grain is separated from the chaff — the juice by treading, and the grain by threshing. It all bespeaks the heavy and powerful dealing of God in the lives of His people in the time of harvest!"
"The great purpose of the harvest now under consideration is so that the husbandman may gather that final harvest of the age, for the harvest is the end of the age, not specifically to plant more seed and extend his fields, but for the purpose of gathering the wheat into the garner, and creating a new kind of bread for the new order to come forth. Thus the bread is a word and a people created to satisfy the hunger of the groaning creation! In like manner, the grapes are for the purpose of yielding wine, and wine is the life-blood of the grape. As the grain is made into bread, that is, a word and a people, so the husbandman oversees the treading of the grapes that there might be also a new and abundant out-flow of the spirit of life unto creation. The winepress is not evil but good. The Son of man did not come to destroy grapes, but to obtain grape juice. He did not come to squash men and destroy them in a winepress so that their blood will be squeezed out of them in some horrible judgment and execution. He came instead to bring forth a life-flow from them so that the new wine of the kingdom can be poured out as a drink offering and a transforming, life-giving power to all men everywhere!"