Our Gemara on Amud Beis discusses a principle of Oenology, which has halachic and metaphysical implications:

דאמר רבא: כל חמרא דלא דרי על חד תלת מיא – לאו חמרא הוא

Rava said: Any wine that does not contain three parts water to one part pure wine is not regarded as wine, as it is excessively strong.

In those days, the original wine mixture was so potent, that when they actually drank it, they had to water it down.

When we find something in the natural world, the mystics tend to attach a spiritual significance to it as well.  The more prominent or impressive the item is in this world, the more consequential it is in its spiritual manifestation in higher realms.  Sex, food, love and wine all occupy a special place in the mystical world because they are so powerful in this world, and so must represent the tip of the iceberg, and a deeper universal truth.  The Shalah (Toldos Odom:15) famously takes this principle to its ultimate conclusion. He states that every word in Hebrew, the holy tongue, is a metaphor or borrowed term from a spiritual reality. He says the Hebrew word for rain, geshem, is not actually rain. Rather it means the way in which God brings down sustenance and blessings from the upper world to all the lower worlds to allow for growth and development. In this world, rain is the physical manifestation of that, and thus Hebrew uses geshem as a metaphor to represent rain.

Therefore, the process of blending wine with water must also mean something. Dover Tzedek (Kuntres Ner HaMitzvos 2) says that Torah is compared by scripture and rabbinic literature to wine, water and milk (see Ta’anis 7a.)  These must be blended properly to achieve the final refined product of Torah study and action: A perfected soul and character.  (What I am about to say is adapted from the Dover Tzedek but not precisely his thoughts.)

Water represents God’s unvarnished, but also unmoderated, raw truth. Just as water is simple, unprocessed, abundant, clear, and vital to life, so is God’s basic truth in its most unprocessed manner.  

The milk part of Torah represents the sweetness, which is a feeling and sensation. As it states in Shir Hashirim (4:11): “Honey and milk under your tongue.” That is in the realm of the heart.  There are emotional arousals and stirrings that come from Torah which are attitudes, dispositions, moods and mental states which are not rooted in rational, linear thought.  And just as it stays under the tongue, so too these ideas, intuitions and perceptions are often better left unsaid, as they are in a mystical, impressionistic form and defy explicit verbalization or representation. 

Finally, we have the wine part of the Torah, which is the product of fermentation. This is the derived wisdom that comes from creating a balanced mixture of raw truth, impressionistic truth, and deductive analysis (water, milk and wine). Just as one can justifiably argue that wine is the most refined and cultivated food, a unique encounter between Man’s technology and Nature, leading to altered states, the same can be said regarding the Torah thoughts and states of mind that comes from a fully integrated assimilation of Torah.