Photo: Sarah Riechers-Krippner
Pastry flour and cake flour don't contain much gluten because the leavening of cookies, pastries and cakes is built on a combination eggs, shortening, sugar, baking powder and incorporated air. In fact, too much gluten can ruin a cake or cookie by making it chewy and rubbery when it needs to be fall-apart tender. For that reason, pastry flour and cake flour are milled from soft red wheat, giving them a protein content of less than 10%. Cake flours have the lowest protein content, while pastry flours contain a bit more gluten to produce the slightly chewy texture we expect from well-constructed pastries.