Mature 46--Old Lake District Sourdough Starter. Why Choose Our Sourdough Starter?. Our 46--Old Lake District Sourdough Starter embodies tradition and passion, crafted with love in an organic bakery. Food Specifications: Organic,Certified Organic,Quality Assured Allergens: Gluten,Rye Flour Flavour: Rye Product: Organic Sourdough Starter.