How it works

The loop, explained with a loaf of bread.

Every open question in science works like a kitchen mystery: you know how things should go, something doesn't, and you test your way to the answer. Here's one you can solve in a few clicks.

The mystery

Promised 2.0×Actual 1.3×

The recipe promised the loaf would rise 2.0×. It rose 1.3×.

So 0.7× of rise is missing. Something is wrong, and we don't know what.

Missing rise explained so far0.0× of 0.7×
Next test

Check that the yeast is alive

Stir a spoonful of yeast into warm sugar water and see if it foams within 10 minutes.

Why this one next: If the answer is "yes, that's the problem", it could explain up to 0.8× of the missing rise, and it's the best value for the effort (free · 10 minutes).

Free · 10 minutes

The loop

Every test goes all the way round. Run the first one and watch each step fill in.

  1. 1 · What we don't knowIs the yeast still alive?
  2. 2 · The testCheck that the yeast is alive
  3. 3 · The result

    What the test shows.

  4. 4 · The picture updates

    Suspects are ruled out or confirmed; the gap is re-measured.

  5. 5 · What to test next

    Every remaining test is re-ranked.

What we don't know yet

Every possible cause, sorted by why it's uncertain. Each has a test that would settle it.

Never checked

Things that could matter but nobody has looked at.

  • Test #1
    Is the yeast still alive?

    The packet was opened 8 months ago, and nobody has checked it since.

    Check that the yeast is alive · Free · 10 minutes
  • Test #5
    Does chlorine in tap water slow the yeast?

    People argue about it, but nobody has checked with this water.

    Bake two mini loaves: tap water vs bottled · An afternoon

Only a rough guess

Things we have a number for, but a shaky one, or from a single source.

  • Test #2
    How hot does the oven really get?

    The dial says 450°F, but home ovens often run 25–50° off. It's only a guess.

    Check the oven with a thermometer · $10 · 1 day
  • Test #3
    Does this flour need more water?

    A single blog post says so. No one else has tested it.

    Try a slightly wetter dough · An afternoon

Sources disagree

Places where the advice points in different directions.

  • Test #4
    Do you have to knead for 10 minutes?

    One forum says knead for 10 minutes; another says no-knead bread rises just as well.

    Knead one loaf, not the other · An afternoon

The picture: how bread rises

Everything bakers know, in one diagram. Side inputs are the suspects; the last one that changed is ringed.

YeastMakes gasDough traps gasOven sets bubblesLoaf heightTap waterFlour & waterKneadingOven temperature

suspect, untested ruled out a cause new idea

From bread to biology

OpenQuestion runs this same loop on open questions in human disease.

In the kitchenIn scienceOn the fatty-liver question
The dense loafAn open questionWhy fat builds up in the liver in type 2 diabetes
Cookbooks, forums, other bakers' notesPapers, trials, datasets29 papers and 7 dataset records
How bread risesThe causal modelFat supply, fat made in the liver, fat export, body weight
“The loaf should rise 2×”A prediction“Pioglitazone should cut liver fat about 10%”
It rose 1.3×A trial that disagreesA trial measured 54%
SuspectsKnowledge gapsMissing links, numbers poorly pinned down, studies that conflict
Yeast in sugar water, an oven thermometerLab experimentsCell and worm experiments at qualified labs
“The kitchen is too cold” (new idea)A proposed missing mechanismAdiponectin makes the liver burn fat
A baker in Denver shares a resultLabs worldwide feeding one shared modelEvery lab's result updates the same model
Bake again and checkConfirm a new predictionPredict a trial before it reports