They start with 100% American barley (predominately two-row pale malted barley, the remainder is lightly roasted).
After distillation in eau de vie pot stills, the whiskey is aged in used bourbon casks and French oak wine casks, as well as filtered through maple charcoal.
They then finish the whiskey in casks that had held house-made umeshu (a Japanese style of plum liqueur made entirely from California-grown ume fruit).