Bake-Off 2: Fermentation

A wild-leavened loaf from the middle of semester, cut on the bench and defended with the log that produced it

Due: 16 April 2027 · Weight: 30%

The brief#

Bake a bread raised entirely by the starter you have kept alive since week 5, and turn up able to say what the dough was doing every time you made a decision about it.

Pick any bread from the fermentation block: a sourdough boule, a rye built on a sour, a naturally leavened pizza base, bagels. The only formula constraint is that no commercial yeast goes anywhere near it. Choose the bread you have the most left to learn from rather than the one you already got away with once.

Fermentation is read, not timed. A recipe that says “bulk for four hours” is describing one kitchen on one afternoon; a 20% levain at 24 °C and the same levain at 29 °C are not running the same bake, and the second one is finished while you are still waiting for the first. You call the end of bulk on what the dough shows you — how far it has climbed the wall of the tub, whether it domes when you tip it, how slowly it fills a fingerprint — and the log is where you tell us what you saw and what you concluded from it.

Acidity is a choice you make, not a thing that happens to you. A warm, wet, frequently fed build finishing at 28 °C reads lactic: yoghurt, buttermilk, something soft at the back of the palate. A stiff levain, a cooler room and sixteen hours retarded at 4 °C push the same flour towards acetic: sharp, vinegary, closer to the front of the tongue. Either is a good loaf. Pick one, steer for it, and be right about which one you baked when the slice is in front of you.

Something will have gone wrong. It always does, and the bakers who improve are the ones who can name it without being led there. A slack, flat loaf from a student who can say “I ran bulk to 80% at 27 °C and spent the structure, so next time I stop nearer 50%” is worth more here than a handsome loaf with nothing behind it.

What you submit#

Two things, both by noon on Friday 16 April.

The loaf. Whole, uncut, baked within twenty-four hours of the bench session, on the table in the bench room with your name on the paper under it. Idris cuts it in front of you and asks you two or three questions about the crumb. A loaf that arrives pre-sliced, or as photographs, is not marked.

The log. One or two pages, as a PDF, uploaded before you walk in. It covers:

• every feed of your starter for the fortnight before the bake: date, time, ratio, room temperature
• the levain build — ratio, hours, temperature, and what told you it was ripe
• the final dough in bakers’ percentages, including the prefermented flour
• dough temperature at the end of mixing and at least two readings through bulk
• what you observed at each decision point, with the clock time you called the end of bulk
• shape, proof, any retard, and the bake itself: oven temperature, steam, time
• the fault you found, what you think caused it, and the one change you would make

Round numbers are a warning sign. “Bulk 4 h” tells a marker nothing; “mixed 09:10 at 26.4 °C, 40% rise by 12:35, tipped out at 12:50 because the surface had gone slack” tells them everything. Bring the log even if the bake failed outright — a collapsed loaf with an honest record of how it got that way still earns most of what is on offer.

If illness or an oven failure is going to stop you, read the assessment policies before the deadline rather than after it.