The taste of soy protein powder can vary depending on the brand and flavor, but in general it has a slightly nutty and earthy flavor. Some people describe it as having a slightly beany or slightly vanilla-like flavor. Some brands add sweeteners, artificial flavors, and other ingredients to their soy protein powder to improve the taste.
It's worth noting that the flavor and texture of soy protein powder can be affected by the manufacturing process, as well as the quality of the soybeans used. Additionally, the flavor and texture of soy protein powder can also be affected by how it is prepared, such as mixing it with water, milk, or other liquids.
It is important to try different brands and flavors to find the one that best suits your taste preferences.