A dense, gummy sourdough bagel and a flat, wrinkled one are opposite failures with opposite fixes, and the internet hands you the same list of guesses for both. Last weekend I stopped guessing. I mixed one batch of my standard dough, split it three ways, and wrecked two of them on purpose: one third underproofed, one third overproofed, one third left alone as the control. Calipers at every checkpoint, cross-sections at the end. The short version: dense and gummy means the fermentation never finished. Flat and wrinkled means it went too far. Once you know the signs, you can tell them apart from across the kitchen.
One batch, split three ways
I've baked sourdough bagels for two years, somewhere between 15 and 20 batches, and most of my bad batches have traced back to fermentation one way or another. So this test isolated it. I doubled my standard recipe (high-gluten flour, 50 percent hydration, a levain built at 6 a.m.) and portioned 12 bagels at 156 grams each. Every bagel got the same boil: 12 cups of water with 2 tablespoons of barley malt syrup and 1 tablespoon of baking soda, 20 seconds per side. Every bagel baked at 450°F, 7 minutes on soaked cedar boards, then flipped onto a preheated baking steel to finish. I build these boards for a living; the wet burlap keeps the bottom pale and steams the crust while the structure sets, and the flip onto steel handles the browning.
The only variable was time.
- Underproofed: shaped early, boiled 30 minutes later. About 4 hours from mix to oven: 3 hours less bulk than the control, and none of its overnight cold proof.
- Control: my normal schedule. 7 hours of bulk with folds, shape, then 14 hours in the refrigerator.
- Overproofed: 10 hours of bulk, 3 more than the control, then 11 hours in the refrigerator beside it.
All 12 started at essentially the same shaped height, 1.156 inches by the calipers. They did not stay that way.
| Underproofed | Control | Overproofed | |
|---|---|---|---|
| After fermentation | 1.156" | 0.981" | 0.864" |
| After the boil | 1.287" | 1.046" | 0.964" |
| After the bake | 1.528" | 1.583" | 1.228" |
| Oven spring | +19% | +51% | +27% |
The control entered the oven the shortest of the three and finished the tallest. The underproofed bagels entered the tallest and finished in the middle. The height a bagel carries into the oven tells you almost nothing about the bagel that comes out.
Dense, gummy, and stuck to the roof of your mouth: underproofed
The cruel part is how normal they look. My underproofed bagels came out golden and domed, and lined up with the control you might not pick the failures by eye. Then you cut one. The crumb is tight and ragged with no open structure, and the center had undercooked spots at full bake time. Eating one settles it: too chewy, and it sticks to the roof of your mouth.
That gummy center gets misdiagnosed constantly. It reads as underbaked, so the next batch gets more oven time and comes out with a thicker crust around the same gummy middle. The crumb is the problem. A fermented crumb is full of gas pockets that let steam work its way out during the bake; an underproofed crumb is so tight that the moisture has nowhere to go, so the center stays wet while the outside browns on schedule. The oven can't finish what the proof didn't build.
The numbers agree. My underproofed third went into the oven the tallest, 1.287 inches after the boil, and gained only 19 percent in the bake. The control gained 51. That missing spring is the fermentation. The fix is patience in two places: a full bulk (mine runs 7 hours at room temperature with 3 to 4 rounds of folds), then a shaped cold proof of 16 to 24 hours in the refrigerator.
Flat, wrinkled, and all crust: overproofed
Three extra hours on the counter. That was the whole difference between my control and the flattest bagels of the weekend.
By the time the overproofed third went into the fridge it was already slack and spreading, with glossy, loose skins. The next morning it measured 0.864 inches, a quarter of the shaped height gone. Those bagels wrinkled in the boil and baked into flat rings 22 percent shorter than the control. Eating one was strange: the interior chew was actually right, there just wasn't enough interior in the bite. Mostly you were eating crust.
The fix is a clock and a bias. My window is 7 hours of bulk, then the refrigerator for 16 to 24 hours, and 48 at the outside edge. When I'm not sure a batch is there yet, I move it to the fridge early. I once refrigerated a batch that hadn't passed a float test because I was worried about overshooting, and they baked up fine. Cold slows fermentation to a crawl; the counter doesn't.
Bagel dough is supposed to feel too dry
If you come to bagels from sourdough loaves, your hands are the hazard. Mine were. I overhydrated batch after batch when I started, because my hands were calibrated to how loaf dough feels, and bagel dough at 50 percent hydration feels wrong by loaf standards, stiff and dry. It's supposed to. A loaf gets a banneton to hold its shape while it proofs; a bagel gets nothing. The ring has to carry itself through a proof and a boil, with a night in the fridge in between, and low hydration is what makes that possible. My overhydrated batches came out flat and misshapen, browned outside and gummy inside, looking overproofed even when the timing was right.
The other loaf habit to unlearn is shaping at the end. With loaves I let the dough rise untouched and treat the bubbles as precious. Bagels run backwards: you shape halfway through fermentation, at the end of bulk, and let the second half happen inside the shaped ring so the structure sets around the gas. It felt wrong the first time, and it worked anyway.
A levain that wasn't ready
My worst batch ever wasn't a proofing mistake, at least not directly. The levain took far longer than usual to double and I mixed anyway, because the schedule said it was time. Those bagels came out closest to this experiment's underproofed third: very dense, very gummy. Same failure, earlier cause. A levain that isn't ready means the underproofing happened before you ever shaped a bagel.
The fix costs nothing. My recipe says mix at 1 p.m. or when the levain has doubled, whichever comes later. And it has to be an active starter. Discard plus instant yeast doesn't add anything; if that's the plan, use instant yeast on its own and save the discard for crackers.
What the float test actually told me
I used to treat the float test as the gatekeeper. This weekend it called one bagel right and two wrong.
The underproofed bagel sank flat and stayed on the bottom of the bowl, which is exactly what it deserved. But on Sunday morning, straight from the fridge, the control and the overproofed bagels sank at first too, then rose within a few seconds as the boil warmed them. Cold dough is dense dough. If I'd trusted the surface of that pot, I'd have called the best bagels of the weekend failures.
I've also had the opposite case: a batch that never passed a room-temperature float test, went into the fridge anyway, and baked up completely fine. So my working rule: the float test is a density snapshot, not a verdict. Watch the pot instead. Bagels that rise in the boil within a few seconds have been fine every time I've watched for it.
Your bagels shrink in the fridge, and that's normal
Here's the measurement that will save a beginner the most panic. My control bagels went into the fridge at 1.156 inches and came out at 0.981, fifteen percent shorter, and they baked into my best crumb of the batch. Cold dough relaxes and settles. A little morning deflation is not a failure.
The overproofed third settled 25 percent, with slack, wrinkled skins. So, from one measured batch, a rule of thumb rather than a law: settling in the mid-teens came with my best crumb; losing a quarter of the height came with my flattest bagels. The skin tells you more than the number. Taut and slightly puffed is fine. Slack and wrinkled means the structure is going.
How the causes stack
The failures interact, which is why guessing goes badly. A weak levain gives you dense, gummy bagels no matter how long you proofed. Too much water gives you flat ones even when the clock was right. So diagnose from the crumb backward. Cut the worst bagel open. Dense, tight, gummy center: fermentation never finished; check the levain's vigor first, then your bulk and proof times. Flat and crust-heavy with a decent interior: the structure gave out; check hours at room temperature first, then hydration. And the clock is only half the input. My overproofed third needed just 3 extra summer-kitchen hours; the same dough in a cold winter kitchen would run slower.
Where to go next
- Why bagel shops bake on wet wooden boards: the bagel boards page.
- The yeasted version of this diagnosis: why are my bagels flat.
- The boards from this experiment: the classic bagel board.
This test is the first block of something bigger I'm building: a sourdough bagel recipe where every step cites a measured experiment instead of a tradition. More tests are coming through the fall. The email signup below gets each one first.