When one thinks of grandmothers, one does not immediately equate them with technology. Much to my surprise and enjoyment, the last time I visited my grandmother, I found a quite remarkable piece of pottery that was quite impressive from an engineering standpoint. My grandmother called this a French Butter Dish, a Butter Bell, or a beurrier. This dish is designed to keep butter fresh without the use of a refrigerator.
The Problem: Butter, at room temperature, quickly goes rancid if exposed to air (the oxygen in the air actually). Usually, butter is stored in a refrigerator to prevent this process from happening, but all that is really needed is to keep the butter isolated from the air.
The Solution: A French butter dish uses water to seal off the butter from the air. The butter dish consists of two pieces: the bowl, and the cap. The bowl is a standard bowl, it is wider at its middle than at its top and looks like a small round vase. The top is a standard wooden top, with a bell shaped or cone shaped piece of pottery affixed underneath it. The top is turned upsidown and butter is placed into the bell or cone underneath the top, and the bowl is filled about a third full water. When the bell is inverted and placed into the bowl, the water rises above the bell and the butter is isolated from the air above the water.
/ \__________/ \
/ | /##########\ | \
| |# Butter #| |
| A |##########| A |
| i |##########| i |
| r |##########| r |
| | Air | |
| |~~~~~~~~~~| |
| Water |
Because butter is basically an oil, it won’t mix with water. If the butter doesn’t get too hot, it will stick to the inside of the bell, and you will always have fresh butter that’s ready to serve. Unlike refrigerated butter, it will never be too hard, and I much prefer room temperature butter to the rock hard stuff I usually keep in my fridge. As long as the Butter Dish is kept out of direct sunlight, the butter will stay fresh almost indefinitely. For all of these benefits, the butter dish is not perfect. The water needs to be changed every day or two. I place a little salt in the water to keep it from molding. I also drilled a few small holes in my Butter dish to allow air to escape if it gets trapped in the bell after removing butter. If you do not want to alter your dish, you will need to top off the butter frequently, if air is allowed to fill the well left by the missing butter, it will cause the butter to go rancid and defeat the purpose of the pot.
From what I have been able to gather on the internet, The Butter Dish is becoming less and less common. If you want to buy one, even in France, you have to refer to them as a beurrier otherwise, you will be shown a standard assortment of 1 stick butter trays for a refrigerator. The design appears to have originated in the French town of Vallauris. Talking with a few French friends who have never heard of such a dish leads me to believe that these dishes are more popular in America then they are in France right now.
These Butter dishes caught my interest because they are a low-tech solution to two problems, keeping butter fresh, and keeping it soft. Bon Appétit
Hapax: adds "It looks like you'll have better luck if you ask for a "beurrier à eau" -- a water-beurrier"
Maylith: adds "You will have better luck if you Google for "Butter Bell"."
Thanks to lj: for ASCII art.