A shaker is a lidded cup, usually made of plastic, in which protein powder is mixed with water, milk or a plant-based drink by shaking. Many models contain a small sieve or a ball that helps to break up lumps when shaken. Some shakers also have compartments for further ingredients such as dietary supplements or a second portion of powder.
In practice, the liquid is poured in first and the powder added afterwards, which makes even mixing easier. How well a powder dissolves depends not only on the shaker but also on the nature of the powder itself. After use, a shaker should be cleaned promptly, as protein residues can easily pick up odours otherwise. Shakers are particularly good for on the go, as they allow quick preparation without extra kitchen equipment.
How to mix a protein shake so that it is as free of lumps as possible is described in the guide Mixing a protein shake properly, and more on how well powder dissolves is explained in the entry Mixability.
