" The gluten content of the final wheat dough can be manipulated by the cook in a number of ways depending on the ultimate goal, whether it be sturdy bread or flaky pastry. (...) The first trick is to use exactly the right amount of water, for it is water that activates the gluten in flour. Fat is the second trick, and it helps the texture of pastry in a number of ways. Fat coats little packets of flour, waterproofing them and limiting the amount of water that gets in (less water, so less gluten), and it keeps the gluten strands 'short'. Little smears and gobbets of fat also separate the mini layers of dough, so that they form individual flakes or crumbs, not a solid mass. "

― Janet Clarkson, , Pie: A Global History