Sourdough focaccia

A wet, oil-baked pan bread leavened with starter. The lever is a full proof; bake it puffy, not on the clock.

Serves: 8
Active: 30 min
Total: 7 hr 30 minplus overnight starter build

Focaccia is the easiest way into sourdough. There's no shaping, no scoring, no Dutch oven, and no loaf to collapse: the pan holds the dough's shape, and the oil in it fries the base crisp. What it teaches is fermentation. The whole recipe is three ingredients and some waiting, so the only thing that separates a dense slab from a tall, bubbly one is whether you let the dough finish rising. Learn to read "jiggly and doubled" here and you can read it in any sourdough, starting with the sandwich loaf, which is the same dough discipline at a stiffer feel in a tighter pan.

Ingredients

Starter build (the night before)

15g sourdough starter
70g (½ cup) bread flour
70g (5 tbsp) water

Dough

400g (1¾ cups) water, lukewarm
10g (1½ tsp) fine sea salt
150g (~⅔ cup) active sourdough starter from the build above, bubbly and doubled
500g (3⅔ cups) bread flour with all-purpose flour, hold back 25–50g of the water
60ml (4 tbsp) olive oil, divided half for the pan, half for the top

Topping

Flaky sea salt (optional), for the top
2 rosemary sprigs (optional), leaves picked

Method

The night before (~10 pm): stir the 15g starter with the 70g flour and 70g water (a 1:5:5 feed) and leave it covered at about 22°C (72°F). By morning it should have doubled, domed, and be full of bubbles. That peak is when it's ready to use.
Mix (~8 am): in a large bowl, stir the 150g starter into the 400g water with the salt until it's loosely dissolved. Add the flour and mix until no dry flour remains; it will be shaggy and very sticky. Cover with a lid or plate (a towel lets the surface dry out) and rest , ideally somewhere around 24°C (75°F).
Stretch and fold: with a wet hand, lift one side of the dough up and fold it over the middle. Turn the bowl a quarter and repeat, four folds in all. Cover and rest . Do three sets of folds in total, apart. Each set the dough will feel smoother and spring back more.
Bulk ferment: leave the dough covered until it has grown by about half, jiggles when you shake the bowl, and shows bubbles at the sides. At 24°C (75°F) that's about from mixing, folds included. Colder kitchens take longer; trust the dough. (Overnight option: refrigerate the dough now, up to , and carry on in the morning.)
Pan: spray a 23×33cm (9×13 in) metal pan with nonstick spray, then pour in 2 tbsp of the oil. Tip the dough in and flip it once so both sides are oiled. Don't stretch it to the corners yet; it'll relax into them.
Proof: cover and leave somewhere warm until the dough has spread to fill the pan, roughly doubled, and looks puffy and bubbly, about at 24°C (75°F) (longer from the fridge). This is the step not to rush.
Once the dough is puffy, heat the oven to 220°C (425°F).
Dimple: drizzle the remaining 2 tbsp of oil over the top. With oiled fingers, press straight down to the bottom of the pan all over, making deep dimples. Scatter rosemary and flaky salt, if using.
Bake in a metal pan (about 40 in glass; check it for the last 10) until deep golden on top and crisp underneath. The center should read 90–99°C (195–210°F).
Lift it out onto a rack right away so the base doesn't steam soft, and cool a little before cutting. Serve warm.

Why it works

The proof is the recipe. Sourdough leavens slowly because wild yeast is outnumbered by lactic acid bacteria and works at a fraction of the speed of commercial yeast. A focaccia has no shaping tension or scoring to help it rise in the oven, so nearly all its height has to be there before it goes in. An under-proofed slab bakes dense and gummy with a few big tunnels; a fully proofed one is light, with bubbles all through. "Doubled and puffy" is the signal, and the clock is only an estimate.
Temperature sets the timetable. Fermentation roughly halves or doubles in speed with every ~8°C. At 24°C (75°F) this dough is a single day; at 20°C it can take hours longer at each stage. That's why the recipe names a dough temperature, and why a warm spot (oven off with just a bowl of hot water, a proofing box) is the fix for a slow rise.
High hydration makes the holes. With the starter's flour and water counted, the dough is about 83% water to flour. That much water lets the gluten network stretch around large gas bubbles, and the water flashes to steam in the oven to inflate them. The cost is stickiness, which is normal: wet hands handle it, and it eases as the gluten develops.
Folds instead of kneading. In a wet dough the gluten forms largely on its own once the flour is hydrated. Each set of folds lines those strands up and traps gas, building strength in a few minutes of work spread over 90 minutes.
The oil fries the base. Two tablespoons in a metal pan is a shallow fry. The bottom crisps and browns rather than baking soft. Metal conducts heat far better than glass, which is why glass needs longer and browns less underneath.
Dimples stop the dome. Pressing to the bottom of the pan pins the dough down so it rises evenly instead of ballooning in the middle, and the oil pooled in each dimple browns those spots.
The overnight retard trades fluff for flavor. In the cold, the yeast slows more than the bacteria, so acid keeps building while the rise barely moves. The bread comes out tangier. Past ~18 hours it gets sour and the gluten weakens, so it rises less.
Classic pitfalls: baking on schedule rather than on proof (the most common cause of dense focaccia); using a starter that's past its peak or not yet risen; letting the cover dry the surface into a skin; and leaving the bread in the pan to cool, which steams the crisp base you fried.

Wine pairing

Vermentino from Liguria, the home of focaccia genovese. It's a dry, saline, herbal white with enough acidity to cut the olive oil, and it's what Genoa drinks with focaccia at aperitivo. Alternatively, a dry col fondo Prosecco, the bottle-fermented, cloudy style. Its lees give it a bready, slightly sour note that matches the sourdough tang, and the bubbles cut the oil the same way the Vermentino's acidity does.

Sources

Country Roads Sourdough — the recipe followed here: quantities, the 1:5:5 starter build, fold schedule, timings at 75°F, overnight option, and pan and glass baking notes.
Serious Eats / The Food Lab — the hydration and gluten-development reasoning behind no-knead, high-hydration doughs.
Salt Fat Acid Heat — Nosrat's Ligurian focaccia and her case for generous oil in the pan and on top.