Impossible Leavening

At yeast it's pretty tasty!

Breaking News: Scientists have recently classified Earth as a triple planet system, consisting of Earth, the Moon, and something called "Needle's Cake," that is supposedly a rapidly growing cake that has separated from Earth. Scientists predict that Needle's Cake will start nuclear fusion and become a star in three weeks.

—Battle for Dream Island, "Sweet Tooth"

In comedy shows, yeast tends to be treated as far more volatile and powerful than it actually is. A less than stellar baker will add more yeast to a recipe than it needs, often many times more, and the dough reacts explosively. If you're lucky, all that you get is a mess in the kitchen or a pizza that nearly fills the oven as it bakes. However, it's just as common to see the dough explode all over the kitchen or, in extreme cases, come to life as a doughy Blob Monster. Occasionally, baking powder and baking soda, also known for their leavening properties, can cause much the same problems.

Sub-trope of Lethal Chef. Compare Oven Logic, for when the disaster is the result of temperature instead of yeast. If the aspiring chef combines the two, you might as well just start saving for a new kitchen altogether.

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Examples:

Advertising

• This comic-book-style ad ◊ refers to the I Love Lucy episode mentioned below.

Anime & Manga

• One episode of Sailor Moon Stars has Usagi mixing up flour and baking soda. As soon as they throw it in the oven, it explodes and covers the entire kitchen in a thick layer of brown muck.

Comic Books

• There's a Goof Troop story with this happening in Pete's kitchen, then the whole house: When instructed to add 3 drops of ultra-concentrated yeast five minutes before the cake is done, Pete just poured the whole bottle in at the start and went for the TV.
• A comedic What If? story imagines that Aunt May gains the powers of Spider-Man. A loaf of bread goes out of control a la the Lucy example below and she uses strands of the loaf as webbing.

Comic Strips

• In For Better or for Worse, Elly accidentally adds far too much yeast when making a large amount of bread for an event, and hurriedly stashes it in the trash can outside so John won't know. Cue John, in the last panel, staring at a trash can whose lid is being lifted into the air by a tremendous mass of dough.

Films — Live-Action

• The Three Stooges did this, but not with bread — with beer! In "Beer Barrel Polecats", the trio were trying to make their own beer. The directions said to use three cakes of yeast, and each stooge, not knowing the others had already done so, put in three cakes. It ends up spilling out of the large crock they're using to brew it in and they eventually fill a bathtub full.

Literature

• In The Bliss Bakery series, this trope is justified by magical ingredients. Which make it possible to ruin kitchens on a much larger scale. The positive side of this is impossibly fluffy, airy cakes.
• George and Harold attempt to invoke this trope in the third Captain Underpants book after discovering the wonders of baking soda and vinegar volcanoes. Their plan was to write a cupcake recipe that called for two boxes of baking soda and two bottles of vinegar, then leaving it for their school's lunch ladies to make for Principal Krupp's supposed birthday, hoping the baking soda and vinegar would cause the batter to expand and create a small mess in the kitchen. Unfortunately, the lunch ladies decided to multiply the recipe 100-fold to feed everyone in the school (the recipe was meant to produce 10 cupcakes), and they flooded the school with cupcake batter as a result.
• In The Duchess Bakes a Cake by Virginia Kahl, a duchess at a castle gets bored with her usual daily routine and decides that she will bake "a lovely light luscious delectable cake" for the entire castle. Wanting the cake to be as light and fluffy as possible, she puts in an excess amount of yeast before baking it. This causes the cake to expand out of control, burst out of the kitchen, and tower over the castle with the duchess on top of it. The king, queen, and their subjects work themselves silly trying to figure out how to get the duchess back down until they realize they can all just eat the cake, and so that's what everyone does, resulting in a mass Temporary Bulk Change but getting the duchess safely back down to the ground.

Live-Action TV

• In a Christmas Episode of Amen, perpetual bad cook Thelma actually gains some cooking skills from her days in the Army and prepares a delicious Christmas dinner for everyone—except for the rolls. When she calls the chef to thank him for his tutelage, she asks why his bread recipe required five pounds of yeast. The chef tells her that's because his recipe was meant to serve 600, whereas Thelma is only serving six. Cue the oven door opening and the dough engulfing the kitchen.
• In one episode of Family Matters, Urkel, unhappy with a poor grade he got in Home Economics because he couldn't get the bread dough to rise properly, invents his own blend of super-yeast for a redo, which works far too well.
• I Love Lucy. In "Pioneer Women", Lucy tries to make old-fashion bread, but due to misreading the recipe (thinking it was thirteen cakes of yeast instead of three), not only did the dough expand to the point that it took both Lucy and Ethel to lift it, but when the oven was opened, the bread came out in a huge oven-shaped loaf, far longer than the oven was deep, stretching all the way across the kitchen and pinning Lucy to the opposite wall.

Music

• In Das Geheimnis im Hefetig, the story starts by Reinhard Mey baking a cake that explodes quite violently. The explosion is strong enough that it attracts the attention of several secret services.

Puppet Shows

• On Fraggle Rock, Ma Gorg, while making a soufflé, sneezes due to having caught a cold. This causes her to accidentally add too much leavening, making the soufflé grow to a ridiculous size and eventually explode into the ceiling.

Video Games

• The ClueFinders 5th Grade Adventures: The Secret of the Living Volcano: In the intro scene, Leslie states that Owen is helping the cook on the ship after getting approval from the Captain. Just then an explosion of dough occurs with Owen stating there to have possibly been too much yeast in the pizza dough.
• Destiny 2: A lore snippet for one of The Dawning events has happened after Saint-14 messes with the recipe for a treat for several Eliksni children. Notably, this wasn't due to yeast, but rather Saint massively increasing the temperature of the oven. Apparently, he had to block off the Kellsdough with a Ward of Dawn.

Web Animation

• In episode 4 of Battle for Dream Island, Needle adds so much yeast to her cake that it eventually becomes its own planet that easily dwarfs Earth in size.

Western Animation

• Chowder: Mung covers himself in yeast in order to turn himself into a giant so he can stop a giant mold monster that had taken over Chowder's body.
• The ending of the Doug episode "Doug's Cookin'" has Porkchop making a pizza where the dough begins to swell so much that it smothers the inside of the Funnie home and spills out of the windows and front door.
• In an episode of Ed, Edd n Eddy, the trio make pizza. Eddy, ignoring Edd's instructions for the proper amount, dumps in the whole container of yeast for the dough. The dough rises so much that Eddy's fist gets stuck in the dough when he tries to punch it down, and Ed has to bellyflop on it to do the job.
• In one episode of Goof Troop, Pete was making bread dough, and when his back was turned, it started to rise out of control. When Peg asked him how much yeast he put in, he said he followed the recipe which said to put in a pint, only to double-check it and see that it actually said pinch. Upon seeing the growing blob of dough, Pete tried to pass it off that he made enough to last a few months...just before it exploded and covered Pete and the kitchen.
  Pete: [to a smirking Peg] Whatever it was you were about to say, don't say it.
• In Hey Arnold!, the kids of the city work on the world's biggest pizza puff in a bid to break a world record. All seems well until Sid reveals that he misunderstood "tsp" in the recipe. Instead of "teaspoons", he read it as "ten square pounds"! The resulting explosion of dough takes a good deal of the next day to wash off the streets.
  Arnold: Uh-oh.
  Oscar: Look out! She's gonna blow!
• An episode of Johnny Bravo has Johnny make pancakes for a rest home, with his own pancake recipe — 3 parts yeast, 8 parts yeast and yeast enhancer. The result is that the mix turns into a giant bread loaf that destroys the entire building.
• The Mr. Men Show:
  • In the episode "Restaurants", Miss Calamity is baking cinnamon buns (currant buns in the UK version). She names each ingredient she puts in the giant mixer as she puts it in: "Flour, sugar, milk, and just a little yeast to help the dough rise." But later on, she can't remember if she added the yeast, so she adds more yeast. This results in the dough filling up the bun shop, but Mr. Nosy and Mr. Small, who are outside the bun shop, don't even notice and leave without rescuing her!
  • A non-food example happens in the episode "Trains", where Mr. Rude's collection of instant sponges ended up being wet and caused Mr. Persnickety being stuck in the cabin.
  • "Radio" has Mr. Fussy trying to make dough after listening to Miss Helpful's cooking show, but this ends up making a glob of rising dough out of his house thanks to her.
• One of the shorts in the 1989 Nickelodeon holiday special Nick's Thanksgiving Fest, "Thanksgiving Dreams", has a sequence where the two poor kids (who have very little food) are shrunk down to pixie size and find their kitchen is magically full of sentient food, appliances, etc. working on a Thanksgiving feast. While they help out, lots of yeast accidentally gets knocked into the dough, creating a sentient dough blob monster. It's defeated by the boy using pepper to make him sneeze.
• Taken to its logical extreme in one episode of Muppet Babies, where an Imagine Spot has the fifty-foot Piggy Dough-Girl rampaging through the city: Bunsen tells Beaker to use the "Beast Blaster" to destroy it, but he ends up firing a "Yeast Blaster" at it instead, causing it to grow into a full-fledged Planet Eater.
• Utilized in one episode of Pinky and the Brain, where the Brain adds 28 cakes of yeast to a craft counselor's clay in order to get him fired so he can take his job, with Pinky even making a reference to the aforementioned I Love Lucy example.
• Weaponized by The Breadmaster, a villain on The Tick, first as bread bombs that can encase entire buildings when activated, and finally, as a giant souffle that will devour the whole city. Luckily, Tick manages to destroy it by generating a sonic boom while getting shot out of the Human Bullet's cannon to collapse the souffle wholesale, though not before having to disarm a bread bomb by eating it and vigorously punching himself until the expanding bread is unable to sustain its reaction.
• The New Adventures of Winnie the Pooh: When Rabbit has Pooh bake a cake for a party, Pooh completely misunderstands every single one of the instructions and eventually Rabbit gets tired of him taking too long and throws the batter into the oven, which then explosively floods Rabbit's house with batter a few seconds later. The recipe didn't even have any leavening agents in it so how that even happened is a mystery.

Real Life

• Averted because the gluten structures will collapse long before the gases reach critical density to cause an explosion. Without the gluten structures to hold the gases in, the gases will simply poof out of the bread. This will result in a product that kinda looks like Swiss cheese. Also, too much yeast growth will end up eating up the dough, which will result in weakening of the gluten structures rather than extreme expansion. With some additional containment, though — such as sealing your fermenting yeast mixture in a screw-top glass bottle — it will explode just fine.
• A popular (and rather disgusting) practical joke is to throw a cake of yeast into an open latrine pit. Bread dough and wine actually lack the nitrogen nutrients needed for the yeast to thrive (that's the reason why moonshiners are often shown throwing the fertilizer into the wort), but the shit most emphatically doesn't, and there's enough undigested sugars to make yeast happy. So you will end with an explosion of the most unpleasant kind, if only figuratively.

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