Gluten is the backbone of most baked goods, at least in my kitchen. It’s a protein that holds together breads, muffins, cookies, and more, and is derived primarily from wheat flour. In the presence of water, proteins called glutenin and gliadin link up to make long gluten strands, which then create a network with each other that can hold the air in a loaf of bread, the shape of cookies, and is what gives bagels their chewy texture. It’s what forms the unique strong-yet-elastic properties of dough that are difficult to recreate with other types of flour.
The amount of gluten you should aim for varies based on the type of item you’re making. The ideal amount of gluten depends based on the desired texture- do you need a strong network to hold buns in their shape? As weak as possible, to keep your cakes lofty and tender but not crumbly? How much gluten a baked good will have is controlled by a few factors: the most relevant in a home kitchen would be the type of flour and how much the mixture is worked.
Flour’s total potential to create gluten is largely a function of how much protein is available to begin with. As an example, cake and pastry flours tend to have protein contents below 10%, and bread flours up to 13-14%, with all-purpose flour falling somewhere in between. The names themselves indicate what they’re intended for. Cakes and delicate pastries don’t benefit from a ton of gluten formation- it makes them tough, they shrink into themselves when they bake, and it gives cakes and muffins undesirable bubbles and tunnels. Breads, on the other hand, require a lot of gluten to hold their loft- the chewiness is pleasant, they can hold the air that yeasts (or chemical leaveners) produce, and gluten allows them to maintain a shape that doesn’t sag or crumble after being baked. Not to say that a recipe is impossible to make with a different type of flour, but it may not turn out as intended.
Flour has the potential to make gluten in the form of proteins that can link up in the presence of water, but like most reactions they benefit from a little mixing. Glutenin and gliadin exist in flour, but it takes a long time for them to find each other and link up without a bit of help. Working a batter or dough allows for these proteins to bump into each other and form bonds, which in turn creates a strong gluten network. This is one of the factors we can exploit in the kitchen to our advantage. When making a cake batter or delicate cookie, we can mix the flour in only until it’s just combined, and in doing so avoid strengthening a gluten network that would make them chewy or tough. For this, I’d recommend doing most of the mixing in a mixer and finishing it with a spatula by hand- chances are, you’ll already have used one to scrape the bowl, and will need it to move the batter or dough from the bowl to somewhere else.
In the case of a yeast-raised bread or pasta dough, we can make sure to work the dough until we get the full gluten potential of the flour- that allows for the flour to give us a chewy texture in a form that holds its shape. I’m a big fan of the windowpane test for bread doughs, where you stretch out a piece of dough thinly enough to see shadows through. For doughs that don’t lend themselves well to that test, a rough indication of gluten development would be a dough that evens out after mixing from lumpy and sticky to become smooth and cohesive.
Strength isn’t Everything
Part of what makes gluten so special is what you might want in a romantic partner- it’s strong, but it has the ability to relax and be flexible. If it was unshakably tough, yeasted doughs would never be able to rise, pastas would never take on their beautiful shapes, and your partner might struggle to express their emotions. Initially, just-developed doughs are very plastic and elastic- they can be pulled and shaped without breaking, but are prone to springing back to their original shapes. Resting doughs allows the gluten network to relax so it’s still there, but it becomes more malleable. This relaxation is caused by the gradual breaking of the weaker types of bonds in the gluten network, but the remaining strength allows the dough to be shaped and retain that new shape. Resting also serves a similar purpose for doughs as for people- continually worked, gluten networks can become so overworked and tight that the doughs get brittle and snap or are difficult to work with, so a dough that becomes unmanageably tense can benefit from a little break. This is more of an issue when mixing doughs in a machine, but even hand-mixed doughs like for pies and pastries benefit from a little rest in the fridge.
This is a small sample of factors that affect gluten in a baked product- things like proportions of salt, fat, water content, pH etc. also have significant roles, but those are generally already taken into consideration when developing a recipe.
Gluten is also not the only factor in the structure of a baked good, considering the existence of recipes without flour (or just without gluten). Components like egg proteins, starches, fats, and gelatin also account for a lot of structure, but gluten is probably the one I mess around with most.