Why do Twirls taste different to dairy milk?

Why do Twirls taste different to dairy milk? Although the recipe and ingredients for our chocolates are always controlled to tight recipe standards, on occasions ingredients are sourced from different areas, and milk particularly can taste differently when bought from different areas of the country.

Although the recipe and ingredients for our chocolates are always controlled to tight recipe standards, on occasions ingredients are sourced from different areas, and milk particularly can taste differently when bought from different areas of the country.