Sirious Science: Over-Mixing

You've met a lot of my family on this blog.  My mom, my sister Hannah, my brother Dylan, and now I want to introduce you to my youngest sibling... Georgia.  Georgia is a freshman at Syracuse University, on the Rowing team and majoring in Nutrition.  That's right, she's better than all of us.  Broadening her mind, exercising her body and just saying no (NO) to alcohol.  (Don't mess with that image, she's my teeny, tiny sister.)  Georgia's currently taking a Food Science course, so I've asked her to come here from time to time and learn us some things.  Science (and nutrition) was never my strong suit.  SO, ever wonder if recipes are just being bossy when they say, "don't over-stir?"  Ever wonder why the muffins you bake are so dense they could be used as a weapon?  Listen up, there will be a quiz.

If your muffins look like this...

Please, put down your rubber spatula. 

And your biscuits...

Never mind.  That is not a biscuit; that is a hockey puck.

Resist the temptation.  Yes, we all know how hard it is to stand over your bowl of raw dough and not stir the hell out of it; but, really, don't do it.  Mixing, either with your electric mixer or your hands, develops the gluten in the flour, which is what gives your baked goods their texture, structure - basically what makes them really yummy and appealing.  How can you tell your dough is over-mixed?  The end product.  The way it comes out.  If you do it just the slightest bit wrong, it affects your whole recipe, and you'll know.  

MUFFINS...

Rule of thumb for most muffin method recipes, STIR FOR ONLY 10 SECONDS. 

But there are clumps in my muffin batter!  YES.  PERFECT.  Most people don't know that this is the way quick bread mixtures are supposed to look like.  The clumpier the better.  In the oven, the heat will react with the leavening agent in the batter, causing carbon dioxide molecules to form and become trapped in the protein and starch.  This produces the tiny holes that create that bread-like quality.  When all is said and done, your self-control shall be rewarded with a soft and crumbly muffin like this:

(Your muffins should NOT have a high peak and should NOT have a smooth crust on the top.  The inside should be even without tunneling.)

If somehow you still feel obligated to stir until perfectly smooth, the gluten becomes overdeveloped, the air is released and the dough becomes tough.  You'll lose that desired light texture and your product will end up uneven, rubbery, and gross.  

BISCUITS... 

Same goes for biscuits.  Cut the cold fat into the flour using the biscuit method and stop until it's just combined.

But there are chunks of butter in my biscuit dough!  AWESOME.  Leave them there.  The butter chunks will melt, creating gaps, or flakes, where leavening does not occur.  The result?  A perfectly even-celled, light, buttery biscuit.

In short, don't pulverize the dough.  Respect the science and the science will respect your taste buds.