At the heart of Heineken’s success lie pure, natural ingredients: malted barley, water, hops and a small but significant extra called A-Yeast. Heineken’s unique A-Yeast is responsible for the rich balanced taste and subtle fruity notes that have distinguished every single Heineken since the 19th century. Over the years their master brewers continued to perfect their craft, learning that fermenting the beer in horizontal tanks instead of the industry-standard vertical creates the perfect pressure for A-Yeast. That’s what gives each Heineken its characteristic balanced, rich taste.