Hippopotamus - The River Horse

Along the shores of the Caveer Sea lie the Acipenseridae - a group of humans who live entirely on the sea shore. For miles the sea remains but a few feet deep and here are many cultivated farms.
They have domesticated the might hippopotamus which they use to plow their farms
Hippopotami reproduce once a year and every generation yields one white hippo - called the Snowball. The Snowball is used to brew an underwater beer called Boxer's Brew - named after a great ancient leader of the Acipenseridae who lead of flock of hippos across a great desert and settled his people in this area. This miracle introduced hippos to this area though they still remain uncommon is the surrounding lands.
Each Snowball becomes the companion of one of the chosen youth who begin their jouney into joining the Council of Sea, taking on political or diplomatic tasks. Each relationship developed is different and can lead to being a Wizard's familiar, Warlock thingy?????, Druid or Ranger animal companion.
To fruits used in the ritual must be rotted, which produces a natural sweetness. They then get chew and turned to mash before being bottled and buried under the water, protecting the fermentation cycles from sun's cleansing ray and from being interfere with other yeast strains carried in the air. Thus producing a pure and consistent product for thousands of year. Be assured, what you drink today is the same as the ancients drank. Bringing you in connection with the past and reinvigorating the culture.
Due to the amount of work needed to create Boxer's Brew there is little to export and is mainly used during rituals and ceremonies - especially those celebrating the two main harvests each year.
The beer is chewed on and mashed by the hippos strong teeth before being buried and fermented with natural forming yeast.
https://www.bbc.com/future/article/20210622-how-shipwrecked-yeasts-could-change-the-taste-of-your-beer