You may know what you get when you overmix cake batter: a dense cake with tough texture (and maybe some unappetizing gluey streaks as well). But far fewer bakers know that undermixing batter can cause the same or similar results.
So if you’re running into problems with your cake’s crumb, it may just be this unexpected culprit —here’s why.
A mysterious failure — and a lesson learned
Our Test Kitchen team recently ran into a problem while working on the recipe for Sweet Corn and Blueberry Coffee Cake, the latest iteration of our 2023 Recipe of the Year. Senior Recipe Developer Molly Marzalek-Kelly noticed that when the recipe went into cross-testing (a regular part of our rigorous recipe development), some of the tester’s cakes had a thin but noticeable layer of heavy gumminess toward the bottom.
Photography by Rick Holbrook; food styling by Kaitlin Wayne
To fix the issue, Molly says she “tried adjusting baking powder/soda amounts, mixing in different size mixer bowls, mixing by hand, baking in different ovens, and baking in different pans.” But nothing worked, leaving her and her fellow recipe testers stumped.
“After many conversations and brainstorms with [fellow Test Kitchen bakers] Frank Tegethoff and Sue Gray,” Molly continued, “we realized the batters must have been undermixed.My theory is that we fell into the common trap of being so worried we were going to overmix the batter, we instead ended up undermixing and not properly developing the structure needed to support the cake.”
Photography by Rick Holbrook; food styling by Kaitlin Wayne
Further tests supported this theory: Undermixing can yield cakes with dense bottoms, due to lack of gluten development and subsequent weak structure (both of which prevent the cake from rising fully). Extending the mixing time just a bit can solve this problem. The recipe directions for the blueberry coffee cake have now been amended to include this cautionary direction: “ … mix again at low speed for 1 minute; this final mix is key to ensuring the best texture, so don't skip it.”
What happens if cake batter is undermixed?
Flour is a critical ingredient in baking. Not only does it provide bulk in the form of starch, but its gluten is responsible for a cake’s structure.
As you mix your cake ingredients together, the flour’s gluten strengthens and aligns itself into an elastic web that will support the cake as it rises. However, developing gluten past its ideal point makes cake tough, and may also cause it to rise too vigorously and then fall as it bakes, resulting in gummy streaks in its texture. But undermixing cake batter — and thus under-developing its gluten — also poses structural problems: It can yield cake that crumbles easily and doesn’t rise very high, resulting in a dense layer of unrisen batter atop the bottom crust.
Photography by Rick Holbrook; food styling by Kaitlin Wayne
Which types of cakes are prone to undermixing?
Theoretically, the batter for any type of cake can be undermixed, but some cakes are less likely than others to suffer from undermixing. For instance, foam cakes, made by folding sugar and flour into whipped egg whites (think angel food) do fine even if undermixed slightly. Since they contain no fat to potentially interfere with their gluten development, gently (but thoroughly) folding the flour into the batter is sufficient to develop its gluten.
“One-bowl” stir-together cakes, which don’t require any beating, are also fairly immune to undermixing. My favorite stir-together cake, cake pan cake, is so foolproof that the original version called for skipping the mixing bowl and simply stirring everything together right in the cake pan! While it’s possible to undermix batter for a stir-together cake, it’s not likely. By the time all of the various ingredients are thoroughly combined, the flour’s gluten has had sufficient time to develop thoroughly.
Cakes made using the creaming technique seem most prone to undermixing. In order to preserve the air beaten into the creamed sugar/butter mixture, the careful baker may be hesitant to mix the final batter for as long as necessary. The result? Under-developed gluten, and cake with a compressed “soggy bottom” thanks to its inability to rise fully.
Lydia Fournier
Reverse-creamed (aka paste) cakes, like the Recipe of the Year coffee cake, can also suffer from undermixing. This technique starts by slowly beating together butter, sugar, and flour, which coats the flour with fat and helps prevent over-development of its gluten during the ensuing mixing process. Paradoxically, that layer of protection may prove so effective that if the final batter isn’t sufficiently mixed, its gluten runs the risk of being under-developed — with the same unfortunate outcome mentioned above.
How to avoid undermixing cake batter
Short answer: Follow the recipe. A good cake recipe will specifically detail how long to mix the batter. And it’s not always “mix until smooth” — carrot cake batter is lumpy from beginning to end, and even a perfectly smooth yellow cake batter may need another minute for its gluten to develop fully. So if your recipe says “Mix for 2 minutes at medium speed, scrape the bowl, and mix for an additional minute at low speed” — don’t skip that final minute.
Julia Reed
Now, you might be tempted to take shortcuts — especially if you’re a seasoned baker. For instance, if the recipe says to “beat at high speed for 5 minutes,” do you actually set a timer for 5 minutes — or do you wing it? Set that timer!
If the recipe specifies having your milk, eggs, and butter at room temperature, then make sure they are. Room-temperature ingredients are much easier to stir together than those just out of the fridge. And for cream-technique cakes, adding cold milk or eggs to an airy, fluffy mixture of butter and sugar can turn everything into a curdled mess.
Finally, even if the recipe doesn’t say to scrape the bottom and sides of the bowl at regular intervals — do so. For best results, it’s important that the sticky residue you scrape up is re-deposited back into the batter to be fully incorporated.
How can you tell when your cake batter is perfectly mixed?
Some recipes tell you to “Mix briefly, just until combined.” Others want you to “Beat for 3 minutes at high speed, until light and fluffy.” Is there a certain “look” to the perfectly mixed cake batter?
PJ Hamel
While creamed cakes usually call for the final batter to be “fluffy,” that’s not a universal goal. Cake batter may range from thin as heavy cream to dense as porridge, and anything in between. In general, though, look for your well-mixed cake batter to be smooth, with no grainy texture, apparent lumps of butter, streaks of flour, or gooey scrapings from the bottom of the bowl.
Professional recipe writers, like those in our King Arthur Test Kitchen, tell you exactly what to do, how long to do it for, and what the result will look like. So follow a well-written cake recipe (like our recently perfected Sweet Corn and Blueberry Coffee Cake) to a tee, and you won’t be disappointed.
Creaming vs. reverse creaming, foam vs. sponge, and then there's blending ... What do these terms mean, and which technique for mixing ingredients will produce your favorite cake? Find out in our post on cake mixing methods.
Cover photo by Rick Holbrook; food styling by Kaitlin Wayne.
