Buckwheat does not necessarily need to be soaked before cooking. If you prefer a firmer texture, soaking might not be necessary. Cooking unsoaked buckwheat directly will give you a slightly chewier texture. Soaking can yield a softer, more tender texture, which may be preferable in some recipes. If you decide to soak, rinse the buckwheat first, then place it in a bowl and cover it with plenty of water. Allow it to soak for at least 30 minutes, or up to overnight. Then drain the buckwheat and rinse it again under cold water. This helps remove any remaining slimness. Cook the buckwheat as usual, but reduce the cooking time to about 10 minutes.