Concrete grout is a form of cement without a coarse aggregate (like sand) that is commonly used for construction or home improvement projects such as wall tiling. The most common form of grout, it's easy to purchase and use. Mixing concrete grout is relatively simple in theory--just add water--but it can be hard to get the mix just right.
Pour a small amount of water (a cup or two) into a mixing bowl. For the sake of good consistency, it's easier to add grout powder to water, so start with this.
Add small amounts of powder at a time to the water while stirring thoroughly with a mixing stick (do not use a kitchen utensil or something you will mind disposing of). Be sure to mix vigorously enough to keep the mixture free of any lumps.
Continue adding grout powder until the mixture has a pasty, but not doughy consistency. Avoid leaving the mixture too watery, as this will make it difficult to apply and cause it to shrink too much while drying. Likewise, a mixture that is too thick will also be difficult to apply evenly.
Allow mixture to set for 5 to 10 minutes before applying.