Coffee beans can be chopped by using blades rotating at high speed (20,000 to 30,000 rpm), either in a blade grinder designed specifically for coffee and spices, or in a general use home blender. Devices of this sort are cheaper than burr grinders, but the grind is not uniform and will produce particles of widely varying sizes, while ideally all particles should have the same size, appropriate for the method of brewing. The ground coffee is also warmed by friction. But any heating effect is negligible if grinding only enough beans for a few cups of coffee by this method because the process is over in less than ten seconds. Blade grinders create Уcoffee dustФ that can clog up sieves in espresso machines and French presses, and are best suited for drip coffee makers. They are not recommended for grinding coffee for use with pump espresso machines.A blade grinder[1] (also propeller grinder[2]) is a machine that chops material while mixing it, by means of a high-speed spinning blade. Applications of blade grinders for preparing foods include numerous electric kitchen appliances such as blenders (including immersion blenders), food processors, some garbage disposals, and some coffee grinders. The terms "blade grinder" and "propeller grinder" are in popular use to distinguish the blade grinder type of coffee grinder from other types. Other consumer applications include rotary lawn mowers.A blender is a kitchen and laboratory appliance used to mix, puree, or emulsify food and other substances. A stationary blender consists of a blender jar with blade at the bottom, rotated by a motor in the base. The newer immersion blender configuration has a motor on top connected by a sh

ft to a blade at the bottom, which can be used with any container. The blending container can be made of glass, plastic, stainless steel, or porcelain, and often has graduated markings for approximate measuring purposes. In cases where the blades are removable, the container should have an o-ring or gasket between the body of the container and the base to seal the container and prevent the contents from leaking. The blending container is generally shaped in a way that encourages material to circulate through the blades, rather than simply spinning around. The container rests upon a base that contains a motor for turning the blade assembly and has controls on its surface. Most modern blenders offer a number of possible speeds. Low-powered blenders require the addition of some liquid to operate correctly. In these blenders, the liquid helps move the solids around the jar, bringing them in contact with the blades. The blades create a whirlpool effect which moves solids from top to bottom, ensuring even contact with the blade. This creates a homogenous mixture. High-powered blenders are capable of milling grains and crushing ice without such assistance. The hand-held immersion blender has no container of its own, but instead has a mixing head with rotating blades that can be immersed in a container. Immersion blenders are convenient for homogenizing volumes that are too large to fit in the bowl of a stationary blender or, as in the case of soups, are too hot to be safely poured into the bowl. Some of the functions of blenders have been taken over by food processors. In particular, thicker mixtures such as mayonnaise and hummus are conveniently made in food processors.