The Danish term “tandsmør” translates to “tooth butter,” and refers to butter spread so thick on a piece of bread that every bite leaves tooth marks. Never before have I felt so deeply connected to another culture. I bake a lot of bread, and every morning I aim to achieve perfect tandsmør the only way I know how: with spreadable butter directly from a butter bell.
What's a Butter Bell?
While there's evidence that stoneware crocks have been used to store dairy for centuries, the exact origins of the butter bell remain murky; a variety of websites vaguely date its beginnings to sometime between the 16th- and 19th-century in France. But regardless of when it was first created, how it works is a little clearer: softened butter is packed into the bell-shaped lid, which is then inserted in the cylindrical crock that a small amount of water placed in the bottom. The bell shape then creates an airtight seal against the water.
Is a Butter Bell Safe to Use?
Because the fat content in butter is so high, it won’t absorb the water that it comes in contact with. This also means that the butter isn’t exposed to air, supposedly preventing butter spoilage. There is one wrinkle in this theory, however.
The USDA doesn’t even mention food safety concerns regarding room temperature butter, only that butter will go rancid…eventually. But rancidity is defined by a sour flavor that occurs when fats begin to oxidize, and doesn’t actually correlate to food-borne pathogen growth. I was shocked to see this 2014 paper establish that butter stored at 77ºF to 95ºF had an estimated shelf life of 109 days before it would spoil, even though butter stored at that temperature would likely be considered rancid after only six days.
The other tricky thing about a butter bell is the addition of moisture. Bacteria and mold require moisture to grow, and butter on its own has a low enough moisture content to prevent pathogen growth. With the butter now sitting in direct contact with water, there’s actually a chance that a butter bell can accelerate pathogen growth. With that in mind, it’s important to swap out the water every few days, and to use the butter within about 10 days, otherwise you might be disappointed with the results. To test these limits, I left butter in the butter bell and out on the counter to see which would spoil faster. After eleven days, I found wispy strands of mold floating around the water in the bottom part of the crock. The butter itself hadn’t turned, but I still threw it out to be safe. The butter left alone on the counter was fine, showing that the introduced moisture in a butter bell creates more potential for spoilage if the water isn’t changed regularly.
Finally, there’s the question of the air pocket underneath the bell. The more butter you use, the deeper into the bell you go, and the bigger the air pocket between the surface of the butter and water becomes. That air is then trapped against the surface of the butter, risking oxidation faster than a simple covered butter dish.
What’s the Best Way to Use a Butter Bell?
Though it has a potentially spotty record on butter preservation, where the better bell truly shines is in keeping your butter at a perfectly spreadable temperature. Ceramic retains temperatures well, and the addition of water turns a butter bell into a heat sink. Serious Eats considers 60ºF to 65ºF to be the ideal temperature for softened butter. So, in the winter, when my kitchen is 66ºF to 68ºF, the butter bell keeps my butter spreadable and soft at room temperature. In the summer, when my kitchen can top out at 80ºF, the water can actually keep the butter temperature cooler, even if the temperature slightly exceeds the ideal range.
In the summer, I recommend changing the water in a butter bell every day. The average temperature of a cold water tap is between 45ºF to 55ºF, and a daily water change will prevent the butter from going rancid faster while keeping the butter from becoming too melty. In the winter, the water can be changed every three to four days instead, since room temperature will keep butter in the perfectly spreadable range on its own.
As far as filling the bell, first soften the butter by leaving it on the counter for at least 15 minutes, then use a knife or spoon to lightly spread it around a bowl or a plate, making it more pliable. Pack the butter into the bell tightly and, using the same knife or spoon, spread the butter out to the edges of the bell in a smearing motion to eliminate all air pockets. Once you add cold water, the butter will firm up, and if there are any air gaps between the butter and the ceramic, it might fall into the water. If that does happen, don’t sweat it. Pat the butter dry with a paper towel, and re-smear it into the bell, just a little firmer the next time.
Is a Butter Bell Worth It?
While it might have a very specific task and limited preservation abilities, I eat so much bread and butter that I can’t imagine not having a butter bell. While bakers are better served by planning ahead, a butter bell is ideal for snackers in all seasons, albeit ones who are diligent about changing the water.
A Couple of Butter Bells Worth Considering
A Classic Butter Bell: L. Tremain Original Butter Bell Crock
This butter bell has a simple ceramic design with a wide, flat handle so it can rest upside down on the counter, giving you easy access to the butter inside. It comes in a variety of colors to match your kitchen.
Another Stylish Option: Sawyer Ceramics French Butter Keeper
Because a butter bell is designed to stay out on your counter, you want it to look nice. As wheel-thrown stoneware, this model has a more rustic, modern look than a standard butter bell while still offering the same functionality.
What is the best butter bell?
While we haven't formally tested butter bells, the L. Tremain Original Butter Bell Crock and Sawyer Ceramics French Ceramic Butter Keeper are two Serious Eats staff favorites that work well and look good on any kitchen counter.
How long does butter last in a butter bell?
Any butter kept a butter bell should be used within 10 days. The water in the crock introduces moisture, which can cause mold growth to happen faster than if butter is left out on the counter. If the water is changed daily, however, the butter might last much longer than 10 days.
How often should I change the water in a butter bell?
Manufacturers suggest changing the water every three to four days. However, in the summer changing the water every day can help keep butter cooler and spreadable without melting, and preserve the butter for a longer period of time.