The classic coffee kettle can be one of many types of pots used to heat water that also have a means to make or hold coffee. Today the term is most likely to refer to campfire, stovetop or electrically heated pots that have a separate reservoir for the dry grounds. "Coffee kettle" may also be used colloquially to refer to any pot holding coffee, which often contradicts the true definition.
Coffee and water used to be boiled together unmixed in earlier days, thus earning any pot with this capacity the tentative title of kettle. Most people more specifically expect the coffee kettle to represent a way to heat water and hold the grounds in a separate container, to avoid getting grounds in the resultant drink. Some of the most common of these kettles today are percolators, which may be used over a heat source or can be plugged into a wall. As the water heats, it moves up into a top reservoir containing the grounds to mix with them and make coffee.
There are many coffee kettle types available. Inexpensive ones made of aluminum may be used on the stovetop or over campfires. Pricier variants with additional features or higher quality materials could be used on the stove or might be plugged into electrical sources.
The simplest kinds of coffee kettle typically make between four and eight cups of coffee, but some can be much larger and make 16 to 20 cups at a time or more. Most of these pots have a similar appearance with a spout and a handle. Very large commercial or industrial machines may lack the handle and might have a spigot at the bottom of the pot for easier pouring.
Primitive forms of drip coffeemakers may also be considered a coffee kettle, though the definition is a little inaccurate. These have a top plastic or metal basket for grounds over which boiling water is poured into a reservoir or kettle below. What differentiates this from other forms of kettles is that the water doesn’t get heated in the pot, and a kettle is almost always defined by its ability to warm or boil water. In their favor, may drip pots of this type can be used on the stove to reheat coffee.
Electric drip coffee makers, espresso machines, and French presses also rely on water that is heated outside of the pot or “kettle.” These don’t really fit the definition because the pots don’t boil water or make coffee. It’s confusing that this second definition exists and that any pot or holder for the coffee may also be called a coffee kettle, in opposition to its original meaning. Many better prefer the term "carafe" to describe pots that only hold pre-made coffee.
