Swamp Juice

And here we have swamp juice, a disgusting concoction consisting of several repulsive ingredients: roots, bark, and soil, to name a few. The faeries of The Emerald Woodland consume it on the regular. When I inquired about this, they claimed it helped their digestion. I have not seen this brew outside of the woods, suggesting it is not very popular amongst others.

— Professor James Harmony, on swamp juice

Swamp juice is a concoction consisting of several ingredients. It is made by juicing a variety of root vegetables, which include beets, turnips, and parsnips, and combining the juice with pieces of medicinal wood, Misery Mire tea, and literal dirt. It is insanely popular amongst Earth elementals. For the rest of us... not so much.

Commonality

Swamp juice is sold at inns and inside vending machines in metropolitan areas and settlements with an abundance of Earth elementals, such as Cyclone City and Silverneedle Town. It is not commonly found outside of these places, as not many Altairians besides those of the Earth element actually like it.

Taste

Swamp juice tastes... unpleasant, to say the least. At least to those who aren't of the Earth element. The strong dirt flavor and bitterness see to that. However, many Earth elementals appreciate its unique flavor. They consume it on the regular.

Swamp juice is commonly marketed as probiotic, which it is. This hasn't done anything to raise its popularity.