A butter crock is a kitchen tool designed to keep your butter soft and spreadable for up to a month without refrigeration. This French invention works by forming an airtight seal of water around the butter. The water prevents bacteria from reaching the butter so you can safely store it at room temperature. This makes the butter easier to spread and spares you the trouble of warming up a refrigerated stick every time you want to use softer butter.
Remove the lid of the butter crock from the base and turn it upside-down so that the top of the lid is resting on a flat surface. The bottom of the lid should in fact be deep and hollow, so the lid in this position should look something like a bowl or vase.
Put your butter on a flat surface and cut it into chunks. This will help it soften more quickly. Leave the chunks of butter at room temperature for about half an hour. Wait until they have softened without becoming runny.
Place the chunks of butter into the hollow part of the lid of the crock. Pack them in as tightly as possible by pushing on them with a wooden spoon. You may find it helpful to put in one layer of butter chunks, pack them in with the spoon, put another layer of butter, pack it in, and so on until the crock’s lid is full.
Pour clean, cold water into the butter crock until it is about a third full. The exact amount of water necessary varies from crock to crock, but it is better to have more water than too little.
Put the lid back into the crock. The opening to the section holding the butter should be facing upside-down, which will cause the surface of the butter to be submerged in the water. Keep your butter crock at room temperature for up to 30 days. Discard the butter after this amount of time, wash the crock, and fill it with new butter.