We’ve all done it, burned a cake, made tough-as-boulders cookies. What’s most frustrating? If you’re measuring by volume (instead of weight), it usually has something to do with cups. Flour will settles in different ways each time you scoop and dip; one “heaping” cup will contain way more protein than its “lightly dipped” counterpart. Before you preheat the oven, your batters chemistry have changed.
This is why pros trust ratio-based methods over exact recipes. When you know the proportions, there’s no need to guess about scaling any batch up or down, and that means baking becomes less about following directions strictly and more about a science you can control.
Why Baking Is Like Science
Baker’s percentages are a way of organizing ingredient so that every other ingredient in the recipe is expressed in relation to the total amount of flour (see infographic above). This removes the clutter of cup-sizes and puts emphasis on balancing each ingredient with others. A pound cake, for instance, traditionally consisted of equal weights of flour, egg, fat, and sugar; hence its name. The four-to-one ratio result in a rich, dense crumb that stays cohesive.
In contrast, a sponge cake have very little fat but lots of eggs to provide leavening; the resulting structure is light and airy. Understanding these structural characteristics can help you troubleshoot: if your cookies is coming out too flat, chances are there isn’t enough flour compared to amount of fat or sugar.
Beyond simply enriching, fat also has a subtle function: It wraps around gluten strands, keeping them from knitting together into hard networks. This is why bread flour get chewy and shortbread dissolves on your tongue. You can see the effect various types of fat have visualy here. Butter lends its own flavor profile and creates flaky layers (thanks to the water it contains which becomes steam when baked). Shortening give tenderness without adding any flavor like butter does. Vegetable oil will keep things moist but won’t add structure.
So for something like a pastry shell for a delicate filling, shortening would of been best since it allows the filling to take center stage. The decision to use one fat over another is purely a matter of taste vs. It depends on your texture preference in the final product you’re making.
The last part of mouthfeel (i.e., texture) also depends on hydration level as much as on any other ingredient. For example, low hydration doughs (like shortbread and crackers) has very little water compared to flour. Because of this, there isn’t enough moisture to allow gluten formation, resulting in a sandy/crisp outcome. With medium hydration (biscuits, sandwich bread), you get enough structure to maintain shape yet still retain tenderness. And high hydration doughs (think: ciabata, artisan sourdough) is sticky and hard to work with but produce irregular, open structures with great chew. The chart above explains all this well and demonstrates how the amount of water changes the desired outcome.
From crispness to elasticity. More water isn’t necessarily better; it’s more about controlling the effect of that water on the gluten. And then there is temperature control. The more heat, the faster the baking process sets, and that’s what makes for the dramatic oven spring of an artisan loaf or that coveted crisp exterior on a cookie. On the other hand, a lower temperature lets a dense batter such as a cheesecake cook slowly and set gently without cracking or curdling.
Get your ratio down and find its corresponding temperature. If you’re trying to bake a high-hydration, lean bread, you need intense first heat to make sure the dough expands rapidly before it starts to harden. But if you’re working with a low-hydration, high-fat shortbread, you want something gentle enough to keep it from burning until the inside reaches doneness.
Once you master this relationship, you’ll be able to improvise with confidence. When adapting those old family recipes, you’ll instinctively know whether to add some more butter or cut back on the sugar. You will also measure with precision, which results in consistant outcomes every single time.