Metres from the banks of the River Lea, a flock of ducks is waddling. Scattered on the ground beneath their webbed feet is what they’re here for; malted barley kernels of various shades, from pale gold to deepest black. Behind them, rising tall, is the Rose and Crown Maltings, part of the small campus that makes up the headquarters and production facility of French & Jupps—the UK’s oldest existing producer of malted barley. Slim birds these are not. You may not have heard the name Frenc...