Week 9 Bake: Butter, a piece at a time

The brioche and challah bench — building the gluten before any fat goes near it, keeping the dough under 24°C, and braiding from the centre out

19 April 2027

Three hundred grams of butter go into this week’s dough, and not one gram of it goes in until the gluten is already built. Get that order wrong and there is nothing left to salvage.

Before the session#

Two formulas. Brioche, on 500 g of strong flour: 250 g whole egg (50%), 50 g milk (10%), 60 g caster sugar (12%), 10 g salt (2%), 10 g instant yeast (2%), and 300 g unsalted butter (60%). Challah, on another 500 g: 250 g water (50%), 100 g egg (20%), 50 g neutral oil (10%), 50 g sugar (10%), 10 g salt (2%), 7 g instant yeast (1.4%).

The yeast is the number to stare at. Week 1 ran at 0.7%; brioche runs at 2%, nearly three times as much, because 12% sugar pulls water out of the yeast cells osmotically and leaves them working at a fraction of their usual rate. More yeast, more time, or both — there is no third option.

Mix the challah at home first thing, bulk it for 90 minutes, and bring it in the tub. Cube 300 g of butter into roughly 20 g pieces the night before and leave them covered on the bench. You want butter at about 18°C: it should bend when you press it and leave your fingers dry. Butter that shines has already started to melt, and it will split your dough.

In the session#

Three hours. The brioche goes home in your fridge; the challah goes home in a bag, baked.

Mix everything except the butter. Flour, egg, milk, sugar, salt and yeast, on low to combine, then eight to ten minutes on medium. You are mixing to a windowpane before a single gram of fat goes near the bowl. That is roughly double what the same mixer needs on a lean dough, because sugar and egg proteins are both competing with the gluten for the water, and the network has less of it to build from.

This order is not a preference. Butter added at the start coats the glutenin and gliadin before they have found each other, and the dough never comes together — you get a slack, shiny paste that no amount of further mixing will rescue. Build the structure, then lubricate it.

Then the butter, 20 g at a time. Fifteen pieces, each one added only once the last has vanished. Expect fifteen to twenty minutes. After each addition the dough will look curdled and wrong for thirty seconds and then come back; that is normal, and it is also why you add the next piece late rather than early. Probe the dough every five minutes. At 24°C, stop, and put the bowl in the fridge for ten minutes before continuing. Past about 26°C the butter renders out of the dough instead of dispersing through it, and fat pools greasy in the bottom of the bowl. There is no fix for that inside a three-hour session.

Finished brioche dough is glossy, pulls clean off the bowl wall, and windowpanes again — a softer, more translucent pane than week 1’s, because the fat films the strands and lets them slide past each other rather than bond. That sliding is exactly what you will taste as tenderness.

Bulk 45 minutes, then cold. Into a covered tub and into the fridge for 12 to 16 hours at 4°C. At 20°C, 60% butter is a smear and the dough cannot be handled at all; at 4°C it is firm enough to roll and braid. Brioche braids that tear open at the seams were shaped straight from the mixer.

Braid the challah while the brioche bulks. Challah is the lean cousin — oil and egg, no dairy, under a quarter of the fat — so it mixes in ten minutes and shapes warm. Divide your bulked dough into six strands of about 160 g, roll each to 30 cm with a fat middle and tapered ends, and braid from the centre out: braid to one end, turn the whole thing around, braid to the other. Braiding from one end pushes dough ahead of you and you finish with one bloated end and one starved one.

Egg wash is one egg beaten with a pinch of salt, left five minutes so the salt loosens the proteins and it brushes on thin instead of streaking. Wash once after shaping, once after the proof. Proof 45 to 60 minutes — risen, but with the seams still visible — then bake at 180°C for 25 to 30 minutes, to 90°C in the centre.

180°C is deliberately moderate. Sugar caramelises and egg protein browns from around 150°C at the surface, so an enriched loaf colours long before its middle sets. A crust the colour of dark treacle over raw dough is an oven set 40 degrees too high, not a dough problem.

Afterwards#

Bake your brioche tomorrow, straight from the fridge: divide cold, shape cold, then proof two to three hours at room temperature because the dough has to warm through before the yeast does anything. Same wash, same 180°C, 30 minutes for a tin loaf and 12 to 15 for buns.

Log the dough temperature at the end of the pre-butter mix, the temperature when the last piece went in, and how many minutes the butter took. Those three numbers tell you more about a failed brioche than a photograph of it will.

Weeks 10 to 12 all sit downstream of today, and so does your Bake-Off 3 showpiece. The week 9 lecture covers why the fat, the sugar and the egg each behave the way they do.