How are scones different from cakes or breads? Although they have similar ingredients, scones have vastly different textures - denser than cake but more buttery and crumbly than bread. Let's find out how the ingredients and procedure to make scones creates the perfect treat!
Background
Scones are a light, flaky treat famous for being served as part of the British afternoon tea or cream tea. In the UK, they're generally round-shaped and served with clotted cream and jam (and, of course, a delicious cup of tea). However, scones around the world now come in a variety of shapes and flavors - savory and sweet. For example, American scones are generally a lot sweeter and found in a triangle or diamond shape. They're also often thought of as a sweetened American biscuit. What unites all of these scones is their crumbly, easy-to-break-apart texture. How can we perfect such a texture that crumbles in the mouth but doesn't fall apart in our hands?
I love that crumbly yet buttery - but not dry - texture of scones, whether it's blueberry (the ones at Panera Bread are scrumptious), chocolate chip, cranberry, or other. As I bit into a warm scone spread with jam, I wondered how this treat with crunchy edges and a buttery, soft inside had such a perfect crumbly texture. I tried making my own blueberry scones to see if I could attain this ideal crumble, but the first time they were a bit more dry and dense. Researching the science behind these scone ingredients and how they come together could let me recreate the best crumbly scones!
Procedure
Scones are pretty simple to make, although they do require some shaping of the dough. Now, you can have warm, freshly made scones any time of the day! For my specific recipe with servings and measurements click here.
I started by preheating my oven to 400°F. I combined my dry ingredients of flour, sugar, baking powder, and salt in a bowl. I cut cold butter into small chunks and dumped them into the flour mixture, mixing the butter in to form small crumbs. In another bowl, I whisked eggs and milk together before adding this mixture into the dry ingredients in 3 parts. Next, I gently folded in the blueberries. Here, the dough was slightly sticky.
I placed the dough onto a lightly floured surface with floured hands and formed it into a ball. I then flattened the dough into an 8 inch circle and cut it into 8 wedges with a bench scraper. I placed each wedge 2-3 inches apart on a silicon baking sheet and brushed the tops with milk. After baking for 25 minutes, the edges and tops were golden brown and I removed them from the oven to cool.
After sprinkling some extra coarse sugar on top and cutting them in half to spread some jam, it seemed that they were a little drier than I prefer - a bit too crumbly instead of soft and buttery on the inside. Did I bake them for too long? Should I have added more butter in smaller chunks? I hope to answer all these questions with science!
Science!
Compared to chewy breads like baguettes, which can sometimes be quite difficult to rip apart, a crumbly scone should break apart easily into smaller chunks. As mentioned in previous posts on bread and chiffon cake, the main reason for these differences is due to the network formed by gluten. Since all of these recipes contain flour, they will form a gluten network to some extent. Bread, with its high gluten content, is kneaded over and over to align the network and create a smooth dough that turns chewy texture when baked. With scones, we don't want this gluten network to form; we use flour with low gluten content and gently mix so that they remain crumbly rather than chewy and tough! Let's look at some of the ingredients and methods that help prevent this gluten formation.
Flour and Butter:
Two factors in the scone-making process can help prevent this gluten network. First, the dough should not be over-mixed or kneaded more than necessary. Gluten proteins form this strong network when enough liquid is present and the dough is kneaded many times. Kneading creates shearing forces, breaking bonds between randomly aligned strands of gluten, stretching them out, and aligning them - similar to turning wool into yarn. This organized structure is bad for delicate scones. That's why it's important not to mix all the dough too much after the wet ingredients have been added, so it doesn't become too elastic. Over-mixing is also not recommended so we don't lose any air pockets that will help the scone rise and be more airy rather than dense. Gently folding with a spatula or shaping with floured hands is recommended (but it should still be mixed evenly!).
The second way to prevent gluten formation and create a finely textured scone is to add barriers to prevent the gluten proteins from interacting. Butter and other fats are good at preventing the over-development of gluten as they "shorten" the flour, which is why butter is added to the flour before the other wet ingredients. Rubbing the cold butter into the flour is what causes the small, flour-coated crumbs and coarse dough. The butter has to remain solid for those fat pockets, as melted butter will cause the pockets to disappear and the dough will become more like a bread than a crumbly scone (remember, liquids cause gluten formation!). Using smaller chunks of butter, such as grating the butter, allows for a more even distribution of the butter and more fat pockets as well (more crumbs). As it's rubbed into the flour, the butter is divided into small particles, increasing its surface area so more flour can touch it.
Thus, there are layers of flour untouched by fat next to layers of fat embedded in the flour. Gluten is developed in the flour layers, while fat layers melt and turn to steam in the oven, leaving empty spaces between the sheets of dough; after the scone is done baking, where the butter used to sit is now an opening or "break" where the scone perfectly crumbles as it's pulled apart. This is similar to what happens in the flaky dough of puff pastry or short crust pastry, such as in croissants or turnovers (happens to a lesser extent in scones).
Milk:
Obviously, a scone can't just be made from butter and flour. Milk is necessary for all the dough to stick together so the ingredients don't crumble apart before being baked. The dough should only be slightly sticky and wet, and not perfectly smooth, as the moisture allows the dough to rise when it turns into water vapor. However, if there's not enough liquid, the dough will fall apart too easily and the final scone will actually be too crumbly. Additionally, if the dough isn't mixed evenly there may be clumps of flour or areas with lots of water that won't hold together.
Replacing the milk with different ingredients can also affect the final scone texture. Replacing half the milk with cream produces a denser scone, while using buttermilk makes a lighter, more bread-like scone. Buttermilk has a creamy texture that makes baked goods tender. Additionally, the lactic acid from buttermilk reacts with the baking powder to increase the amount of carbon dioxide gas produced, leading to a greater volume and lighter texture.
Other Ingredients:
The additional rise comes from baking powder by puffing up the scone as a whole in the oven. The scones should also be cut pretty thick for this to happen. The sugar helps to brown the scone more quickly in the oven through the Maillard reaction, mentioned in the science of many other baked goods. Sugar also adds sweetness, tenderizes, and aids browning and a fine texture.
The flavor additions, such as blueberries, can also affect how crumbly the scone is. Fruits contain a lot of moisture, so they should be added near the end when dough is being formed and combined together. The fruit should be folded gently so they don't break apart and release more moisture, as that would lead to more gluten formation. A good fruit is actually cranberries because they barely release any moisture. One possibility for juicy fruits is to reduce the amount of milk.
Finally, a hot or very hot oven (425 to 450°F) is necessary so the butter immediately melts and all the moisture turns to steam, causing a fluffier and brown-crusted scone. Low oven temperatures may lead to dense or heavy scones, as the butter slowly melts and wets the flour, creating excess gluten. Additionally, resting the dough in the fridge 30 minutes before making can help to relax the gluten strands, which produces a fluffy texture and prevents shrinking in the oven.
Conclusion
Who knew we could create the perfect crumbly scone through science! Now I know that to get crumbly yet soft and buttery scones, I need to use flour with low gluten content, plenty of cold butter grated into small pieces to coat the flour evenly, milk to help the dough come together, enough baking powder to help it all rise into a fluffy scone, and a very hot oven so the butter evaporates immediately for those flaky layers. It's also extremely important not to over-mix or knead to prevent gluten networks! It would be interesting to try replacing milk with buttermilk or cream and see how that affects the scone texture in future experiments. Another idea could be using self-rising flour, without needing additional leavening agents, to see how crumbly those scones are. Now that we know all the factors that affect the crumbly texture of scones and the science behind the concepts, we can make our own idea scones!
Link to my blueberry scone recipe.
Link to my post on the history & culture of scones.
Want to Learn More? (always cite your sources, kids)
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