Enriched Doughs.
Brioche is half butter by the flour's weight. Added at the start it would stop the gluten forming; worked in at the end, a little at a time, it makes the softest crumb there is.
An enriched dough adds fat, sugar, eggs or milk to flour, water, salt and yeast. Each brings richness and softness and each slows something. Fat coats the gluten proteins (IX.9), so a dough with a lot of butter develops slowly and is kneaded first and enriched after — brioche's butter is beaten in, cool and soft, once the gluten is strong. Sugar above about 10 % of the flour draws water away from yeast by osmosis and slows it markedly (XX.1); sweet doughs use more yeast, or an osmotolerant ("gold") instant yeast. Milk and egg add solids and fat; their water counts towards hydration (XXIV.3).
Two techniques help. A preferment — 中种 (sponge), part of the flour fermented first with the yeast — gives the yeast a head start before sugar and fat arrive. And 汤种 (tangzhong, or yudane in Japan): about 5–10 % of the flour cooked with five times its weight of water or milk to a paste at 65 °C, cooled and added to the dough. The gelatinised starch holds much more water (VII.1), so the dough can be wetter without being sticky, and the bread is soft, fine and stays fresh for days — the Hong Kong and Japanese milk loaf. Enriched breads brown fast (VIII.3) and are baked cooler, done at 88–93 °C. The workshop enriches a dough.
Below: for a bread-flour dough with the butter and sugar you choose, the gluten it develops with twelve minutes of kneading (course model: fat coats the proteins) and the time it takes to double with 1.5 % instant yeast (course fermentation model: sugar above 10 % slows yeast), with and without a tangzhong adding water.
- Explain how fat, sugar, egg and milk change a dough.
- Add butter at the right stage.
- Adjust yeast for sweet doughs.
- Make a tangzhong milk loaf.
Strengthen first, enrich second, give it time
In the course models, kneading a dough with 50 % butter from the start gives gluten of only 0.25, against 0.84 with none — which is why brioche is kneaded strong first and the butter beaten in after. Raising sugar from none to 20 % stretches the doubling time from about 1.2 to 1.7 hours at the same yeast. Sweet breads therefore use 1.5–2.5 % instant yeast, a sponge or an osmotolerant yeast, and a warm proof.
Hokkaido milk loaf with 汤种: whisk 20 g of the bread flour with 100 g of milk over low heat until it thickens to a paste (about 65 °C); cool. Mix with 280 g bread flour, 25 g sugar, 5 g salt, 6 g instant yeast, 1 egg and about 110 g milk; knead until smooth and strong, then work in 30 g soft butter until the dough passes the windowpane test (XXIV.4). Rise until doubled, divide in three, roll each up, place in a loaf tin, proof until it crowns the tin, brush with egg, bake at 175–180 °C for about 30 minutes, to 88–93 °C inside. It stays soft for three or four days (XXIV.11).
Make the same milk-bread dough with and without a tangzhong. Keep a slice of each in a bag and compare their softness over three days.
Terms
- Enriched dough
- A dough with fat, sugar, egg or milk.
- 汤种 (tangzhong)
- Flour cooked with water or milk to a paste, added to a dough.
- 中种 (sponge)
- A preferment of part of the flour with the yeast.
- Osmotolerant yeast
- Yeast that works in high-sugar doughs.
Sources
- A teaching value chosen for the course: the right order of magnitude and shape, not a measurement of a particular food.
- H. McGee, On Food and Cooking: The Science and Lore of the Kitchen, 2nd ed., Scribner, 2004.