Why does a Butter Bell need water?

Why does a Butter Bell need water? The answer remains in whether you keep your butter on the bench or in the fridge? The butter bell and it's butter keeping technique was developed before refrigeration as a way to keep butter fresh.  Back then (and what is becoming more and more common today with home cooks)  butter was made from fresh cream and salt. Without a fridge to keep the butter fresh, the water in the bottom of the butter bell as a 'seal' to keep bacteria out. 

Butter Bell or Butter Dish? Which is better

Butter Crock vs Butter Dish: Which Is Better? By The Eumundi Trading Co · Eumundi, Queensland A butter crock and a butter dish both sit on your kitchen bench and hold butter. That is where the similarities end. One is a centuries-old French design that keeps butter genuinely fresh at room temperature for up to 30 days. The other is a lid you put over butter and hope for the best. If you are trying to decide between the two, this guide will make the answer clear. What Is the Difference Between a Butter Crock and a Butter Dish? A butter dish is a simple two-piece set: a flat plate and a cover. The butter sits on the plate, the lid goes on top, and that is the extent of the preservation. There is no seal. Air circulates freely around the butter, which means oxidation — the process that makes butter go rancid — continues uninterrupted. A butter dish is better than leaving butter completely uncovered, but only marginally. A butter crock — also called a Butter Bell®, French butter keeper or bell crock — works on an entirely different principle. The butter is packed into a bell-shaped lid and inverted into a base that contains a small amount of water. The water creates an airtight seal around the butter, blocking oxygen completely. No oxygen means no oxidation, which means the butter stays fresh, soft and flavourful for up to 30 days at room temperature. The distinction matters more than it might seem. If you have ever noticed butter on the bench developing a slightly yellowed outer layer, a dull flavour or an off smell after a few days, that is oxidation at work. A butter dish does not prevent it. A butter crock does. Butter Crock vs Butter Dish: A Direct Comparison