Measuring spoons are still useful for very small quantities because kitchen scales often lack the precision to accurately weigh amounts less than a gram. While you *could* try to measure 1/4 teaspoon of baking powder on a scale, it's generally not recommended due to accuracy limitations.
Kitchen scales, even digital ones, typically have a minimum weight they can reliably measure. This is often around 1 gram or even higher. A 1/4 teaspoon of baking powder weighs approximately 1 gram. Therefore, while *technically* you might be able to get a reading, the accuracy is questionable. The scale might fluctuate, or the reading might be off by a significant percentage, especially if the scale isn't high-precision.Furthermore, the distribution of the baking powder on the scale can affect the reading. A small pile in the center might register differently than the same amount spread thinly across the platform. Measuring spoons, while not perfect, offer a more consistent and practical way to measure these tiny amounts. They are designed for these small volumes and provide a more reliable result than a scale struggling at its lower limit. For larger quantities, a scale is generally more accurate and preferred, but for those tiny pinches and dashes, measuring spoons remain a valuable tool.
When using measuring spoons, avoid scooping directly from the container, which can compact the ingredient and lead to inaccurate measurements. Instead, lightly spoon the ingredient into the measuring spoon and level it off with a straight edge, like the back of a knife.