Soak the buckwheat groats for at least 6 hours (I soaked them in a large mixing bowl covered with a dishcloth). Drain and rinse.
Add the buckwheat groats and the water (1 cup or 250 ml) to a food processor and blend until well combined. If you don’t have a food processor, feel free to use an immersion blender or a regular blender, but don’t over blend.
Place the batter in a large mixing bowl, cover it with a dishcloth, and let it ferment at room temperature for at least 12 hours.
Preheat the oven to 350ºF or 180ºC.
Add the salt and the seeds to the batter and stir with a spoon until well combined.
Pour the batter into a loaf pan lined with parchment paper.
Bake for 1 hour and 15 minutes or until golden brown.
If you use parchment paper, feel free to remove the bread from the loaf pan immediately, but let the bread cool down for at least 30 minutes before slicing.