Mix the flour and buttermilk together. Cover and soak12-24 hours, or overnight. (If using sprouted flour, the soaking process can be skipped).
Preheat the oven to 450°F.
Cut butter into chunks, then work it into the flour/buttermilk mixture along with the baking soda, baking powder, and salt. Do not over-mix. If the mixture is too dry, add a bit more buttermilk.
Turn the dough onto a lightly floured surface. Gently pat the dough out to ½-inch thickness. (Patting instead of rolling will yield lighter biscuits).
Use a round cutter to cut out the biscuits. Place biscuits on a cookie sheet. If you want biscuits with soft edges (and a higher rise), place the rounds touching each other. If you want biscuits with crusty sides, place the rounds about 1 inch apart.