Emma Zimmerman co-founded Hayden Flour Mills in Arizona, USA with her father Jeff Zimmerman in 2011. The family business is devoted to making the freshest and tastiest flours from some of the world's oldest varieties of wheat. Today, Hayden Flour Mills grows multiple different heritage and ancient grains. The grains are milled into heritage baking mixes, stoneground polenta, pasta flour, pizza flour and artisan bread flour. Hayden Flour Mills' products have a loyal following and are available in 500+ retail stores including Whole Foods Markets and Eataly. Their flours have also been featured in Martha Stewart Living, Eating Well, Saveur, Bon Appetit, and Marie Claire.

Emma was also named by Marie Claire as one of "Six Women Who Make Going Big in the Food World Look Like a Piece of Cake".