Ingredient

Sourdough

Sourdough is bread raised by a culture of wild yeast and lactic bacteria instead of packet yeast. It takes far longer, tastes considerably better, and the whole skill is learning to judge the dough rather than the clock.

What a starter is

A stable community of wild yeasts and lactic acid bacteria living in a flour-and-water paste. The yeasts produce carbon dioxide, which raises the bread; the bacteria produce lactic and acetic acid, which give the flavour and strengthen the gluten.

It is made simply by mixing flour and water and feeding it daily until it becomes reliably active — usually a week or two. It looks alarming for the first few days while the wrong organisms dominate, and then settles down.

A starter is ready to bake with when it reliably at least doubles within four to six hours of feeding and smells pleasantly sour and yeasty rather than sharply of acetone or nail varnish. If it smells of solvent it is hungry — feed it more often.

The bake, in outline

Times are indicative and temperature changes everything. Judge the dough, not the clock.

1. Feed the starter and wait until it is at its peak — domed, bubbly and just beginning to recede.
2. Mix flour and water and let it sit for an hour before adding anything else. This autolyse hydrates the flour and makes the dough far easier to handle.
3. Add the starter and the salt and mix thoroughly.
4. Bulk ferment at room temperature for four to six hours, giving the dough a set of stretches and folds every half hour for the first two. It is ready when it has risen by perhaps 50%, feels airy, and shows bubbles at the surface and sides.
5. Shape it, tightening the surface without tearing it, and put it into a floured banneton.
6. Prove in the fridge overnight. Cold proving develops flavour and makes the dough far easier to score.
7. Bake very hot in a preheated cast-iron pot with the lid on for twenty minutes — the trapped steam is what gives the rise — then uncovered until deeply coloured.

Why loaves come out dense

• The starter was not active enough. Use it at its peak, not straight from the fridge.
• Under-fermented. The commonest cause. The bulk ferment needs to actually finish, and in a cool kitchen that takes much longer than a recipe suggests.
• Over-fermented. The gluten has been degraded by acid and can no longer hold gas. The dough is slack, sticky and soupy and will not hold a shape.
• Poor shaping. A loose surface cannot hold the gas. Shaping should leave a taut skin.
• Not enough steam. Without it the crust sets before the loaf has finished rising. A lidded pot solves this entirely.
• Cut too soon. Sourdough must cool completely, or the crumb is gummy — the starch has not finished setting.

Judging the dough

The poke test

Press a floured finger in. It should spring back slowly and not quite fully. Springing back fast means under-proved; not at all means over.

The windowpane

Stretch a piece thin. If light passes through without tearing, the gluten is developed.

The aliquot jar

Put a small sample of dough in a straight-sided jar and mark it. It shows the rise percentage far more clearly than the bulk mass does.

Temperature

The single biggest variable. At 22°C a bulk ferment might be six hours; at 26°C, three.

The ear

The raised lip at the score. Nice to have, and no indicator of a good loaf.

Common questions