Line three baking sheets with waxed paper and set aside.
In a heavy saucepan over medium-high heat, bring the sugar, baking soda, salt, and buttermilk to a boil, stirring constantly. Boil five minutes or until a candy thermometer registers 210°. Add butter, syrup, and pecans and return mixture to a boil. Boil five minutes longer, stirring constantly or until a candy thermometer registers 232°.
Remove from the heat and beat with a wooden spoon for two minutes or until the mixture begins to thicken. Quickly drop tablespoons of the candy onto the prepared sheets. Allow pralines to stand at room temperature until firm. Store in an airtight container between layers of waxed paper.