Category Atlases · Article 13

Bread Atlas & Sourdough

A reference article · 3,700 words · 46 cited sources · last reviewed October 2026 · fact-checked October 2026, 59 claims

A bread style is a formula read as a set of levers. This atlas maps lean, enriched, rye, and world breads, then goes deep on the living microbial ecosystem that makes sourdough work.

Numbers are in baker’s percentages (ingredient ÷ total flour × 100). Contested/simplified claims are flagged.

Reading a formula as a style

A bread style is defined not by shape or name but by five formula levers.

Hydration (water as % of flour) is the primary lever. Roughly: about 50–60% gives a stiff, tight-crumbed dough (bagels, pretzels); about 60–70% covers conventional pan and hearth loaves; 75–85% and above gives the slack, open-crumbed doughs (ciabatta, many country loaves); and around 100% or more is a very wet dough or a batter (pan de cristal, some ryes, injera). King Arthur describes doughs at 55–65% as likely to feel firm or even stiff and those at 75–85% as slack (King Arthur Baking, 2023). Water governs enzyme mobility, gluten development rate, gas-cell wall thinness, and crumb openness.

Salt (about 1.8–2%; 2% the usual default) tightens gluten by screening the charges on gluten proteins, slows fermentation and enzymes, and helps crust color by leaving more sugar unfermented (BAKERpedia, n.d.-a; McCann & Day, 2013). Saltless Tuscan pane sciocco is slack, fast-fermenting, pale by design.

Preferment / leaven type (none, commercial yeast, poolish/biga/sponge, or sourdough) sets flavor complexity, acidity, dough strength, and timescale.

Fat and sugar convert lean (flour/water/salt/leaven: crackly, chewy hearth breads) into enriched (fat, sugar, eggs, dairy: tender, colored, soft, longer-keeping, but interfering with gluten and slowing fermentation).

These produce the classical dichotomies: lean vs enriched (fat/sugar axis), hearth vs pan (free-standing loaves need strong gluten and skilled shaping and bake on stone with steam; pan breads are supported and run softer/enriched), flatbread vs risen (gas retained by a developed network vs largely released).

The lean dough atlas

Lean dough is where technique, not ingredients, makes the bread.

French family. The baguette: about 65–68% hydration (Hamelman’s poolish baguette is 66%), French T55/T65 flour (an ash grade, so protein varies by mill, roughly 10.5–12%), often built on a poolish (equal weights of flour and water plus a pinch of yeast, fermented 12–16 h at room temperature in Hamelman’s method) for nutty flavor and extensibility (Hamelman, 2004). It is defined by shaping to a taut sealed cylinder, proofing in a floured couche, and scoring with the blade held at a shallow angle of about 30° so the cut lifts into an ear (America’s Test Kitchen, n.d.-a). Pain de campagne adds 10–30% whole wheat/rye and a levain (fuller flavor, tighter-but-open crumb, longer keeping). Pain de mie is the French pan loaf, lightly enriched, lidded pullman tin, tight square tender crumb.

Italian family. Ciabatta, 75–85% hydration (about 80% is typical), often on a stiff biga (about 50–60% hydration), handled with folds not kneading, minimally shaped, wide-open glossy crumb (the defining move: preserving gas by handling wet dough gently). Focaccia, typically about 70–85% hydration (some versions higher), pressed into an oiled pan, dimpled for oil/brine. Pane (Pugliese; Altamura from durum semola), rustic rounds with long fermentation.

The rustic high-hydration open-crumb loaf (the Tartine-style country loaf): 75–85% hydration, 10–20% whole grain, young sweet levain, long bulk with stretch-and-folds/coil folds, gentle two-stage shaping, long cold retard. Defined by building strength through folds and time rather than intensive mixing.

Bagels & pretzels invert every rustic instinct: low hydration (bagels about 50–60%), high-gluten flour (about 14% protein), malt or another sweetener. Sources differ on the exact band: Phillips (2024) puts bagels at 50–57%, Hamelman’s bagel is 58%, and King Arthur gives 55–65% (King Arthur Baking, 2021a). Bagels are shaped, cold-retarded, then boiled (often with barley-malt syrup) to gelatinize the surface for chewy shine. Pretzels are dipped in a food-grade lye solution of 3–4% sodium hydroxide by weight (or a weaker baking-soda solution) for intense Maillard browning (King Arthur Baking, 2021b); Laugengebäck means “lye pastry.”

Pizza doughs. Neapolitan, under the Associazione Verace Pizza Napoletana (AVPN) rules: soft-wheat type 00 or 0 flour, 1.6–1.8 kg of flour per liter of water (about 56–63% hydration), 40–60 g of salt per liter (about 3% of the flour), a tiny amount of yeast, long fermentation, baked 60–90 s on an oven floor of about 715–805 °F (380–430 °C) under a dome near 905 °F (485 °C) (Associazione Verace Pizza Napoletana, 2024). New York: about 60–65% hydration plus oil and sugar, higher-protein bread flour, cold-ferment 24–72 h, baked at about 500–550 °F (260–290 °C). Roman al taglio: about 75–85% hydration, long cold ferment, airy honeycomb.

Rye and whole-grain breads

Why rye behaves differently. Rye’s proteins don’t form a functional gas-holding network. Structure comes instead from arabinoxylans (pentosans) together with starch (Deleu et al., 2020). Arabinoxylans are far more abundant in rye than in wheat: about 8–9% of whole-grain rye flour (Andersson et al., 2009), less in light rye flour, against roughly 1.5–2.5% in white wheat flour. They hold several times their weight in water, which is why rye doughs are sticky, dense, paste-like. Second, rye starch gelatinizes at a relatively low temperature while rye’s abundant α-amylase is still active; unchecked, the enzyme degrades the swelling starch and gives a gummy, sticky crumb (Deleu et al., 2020). The corrective is acidification: amylase works best around pH 5.4–5.8, and finished rye breads typically sit around pH 4.3–4.7, coarse ryes a little lower (Metrohm, 2021). That is why rye is almost always a sourdough.

Rye by percentage. Light rye (10–40%) behaves like flavored wheat bread. Past ~50%, sourdough is mandatory. High-percentage/100% ryes, German Roggenbrot, Vollkornbrot (whole-grain, soaked kernels) and pumpernickel (at least 90% coarse whole rye, baked for at least 16 hours at low temperature in steam-filled closed tins, its dark color and sweetness coming mainly from slow Maillard reactions, not coloring) (Yumda, n.d.), are dense, moist, and rested 24+ hours before slicing.

The Detmolder multi-stage sour. The classical German method for controlled organism populations and acid balance. The three-stage (Dreistufenführung) runs a seed through three builds, each at its own temperature, firmness and time: a soft, warm Anfrischsauer (about 77–79 °F (25–26 °C), 5–6 h) that builds yeast; a stiff, long Grundsauer (about 73–81 °F (23–27 °C), 15–24 h) for aroma and acetic acid; and a soft, warm Vollsauer (about 82–86 °F (28–30 °C), about 3 h) for acid and leavening (Pistor, 2019). The multi-stage build tunes the lactic:acetic ratio with a precision a single build cannot. Guidance for where a ripe sour should land differs: Swiss trade guidance puts it near pH 3.8–4.0 with an acidity degree of 10–13, calling sours below pH 3.6 and above 15 strong (Pistor, 2019), while industrial rye sours measured in Estonia ran at about TTA 15–25 (Viiard, 2014).

Whole-wheat handling, soakers, scalds. Bran and germ dilute gluten, sever strands, add enzyme/oxidative activity, absorb water slowly. Reinhart’s “epoxy method” pairs a soaker (whole flour + water + salt, overnight: hydrates and softens bran, begins enzymatic sweetness) with a biga or levain (flavor and strength) (Reinhart, 2007). A scald (Brühstück) pours boiling water over flour/grains to gelatinize starch and inactivate enzymes, pre-hydrating, sweetening, and dramatically improving moisture retention and shelf life. Sprouted grains add amylase and altered starch (sweetness, nutrition, gumminess risk). Seed/porridge breads fold cooked grains and soaked seeds in as internal soakers.

Enriched and soft breads

Enrichment trades open crumb and crackly crust for tenderness and shelf life; the science is interference with gluten plus retardation of staling. Sandwich/pain de mie: lightly enriched, fine even tender crumb. Milk breads / Japanese shokupan: cloud-like crumb from tangzhong/yudane (a cooked flour-liquid paste: about 5–10% of the flour whisked with about 1:5 flour:liquid and heated to about 149 °F (65 °C), or about 1:1 with boiling water and rested) (Leo, n.d.-b); pre-gelatinized starch holds far more water, locking it into the crumb so the loaf is softer and stales slower without feeling wet. Brioche/babka (see Pâtisserie Doughs) emulsify large amounts of cold butter into developed gluten, usually with cold fermentation. Challah is egg-enriched but fat-lean and dairy-free, springy, richly colored. Potato rolls use potato starch/moisture for a pillowy crumb. Parker House uses buttered folded dough for soft layers.

Crumb-softening science. Four levers: higher effective hydration (tangzhong/scald), fat (interrupts gluten and starch retrogradation), sugar/humectants (bind water, slow amylopectin recrystallization, the chemical basis of staling), and enzymes/emulsifiers (commercial amylases, mono/diglycerides). Staling is primarily retrogradation, not moisture loss, which is why reheating partly refreshes stale bread (Goesaert et al., 2009; McGee, 2004).

Sourdough microbiology

What a starter is. A stable, self-perpetuating microbial ecosystem: a symbiosis of wild yeasts and lactic acid bacteria (LAB) in a flour-and-water medium. Stability is the product of selective pressure: each feeding is an ecological bottleneck favoring organisms adapted to that flour, hydration, temperature, and schedule. A mature starter holds roughly 10⁸–10⁹ LAB and 10⁶–10⁷ yeast cells/g, a ratio of roughly 10:1 to 100:1 bacteria to yeast (De Vuyst & Neysens, 2005; Lattanzi et al., 2013).

The dominant organisms and the cross-feeding engine. The emblematic LAB is Fructilactobacillus sanfranciscensis (formerly Lactobacillus sanfranciscensis). Flour’s principal fermentable sugar is maltose. F. sanfranciscensis takes up maltose, splits it, and excretes part of the glucose (Neubauer et al., 1994; Gänzle, 2014). The classic partner yeast, Kazachstania humilis (now also classed as Maudiozyma humilis; formerly Candida milleri/humilis), cannot use maltose and lives on glucose and other sugars, so the two largely avoid competing for the same carbon. This niche separation is the classic explanation for the pair’s stability; Saccharomyces cerevisiae, which usually ferments maltose, competes more directly (Gänzle, 2014).

Homofermentative vs heterofermentative LAB, and the acid balance. Homofermentative LAB (e.g., Lactiplantibacillus plantarum) convert sugars almost entirely to lactic acid (mild, yogurt-like). Heterofermentative LAB (e.g., F. sanfranciscensis, Levilactobacillus brevis) produce lactic + acetic acid + ethanol + CO₂ (acetic = sharp, vinegary tang). F. sanfranciscensis uses fructose as an electron acceptor, shunting toward more acetic acid when fructose is available (Stolz et al., 1995). The lactic-to-acetic ratio (the “fermentation quotient”) is the master flavor dial: warm, wet, well-fed → lactic/mild; cool, stiff, less-fed → acetic/sharp (Gänzle, 2014).

How conditions select the community. Every maintenance variable is a filter. Temperature: yeast and LAB both grow well in the mid-70s to low-80s °F (about 24–28 °C); the classic sourdough bacterium prefers about 90 °F (32 °C), and yeast growth is inhibited near 95 °F (35 °C), which is why very warm starters go acidic and lose lift (Brandt et al., 2004). Hydration: wetter starters ferment faster and make more lactic acid; firm ones run slower and relatively more acetic, and firmness favors the bacteria’s souring over yeast activity (Gobbetti et al., 1995). Flour: whole-grain and rye carry more microbes/minerals/enzymes and ferment faster and more sourly. Feeding ratio/frequency: frequent high-dilution feeding keeps pH higher and flavor mild; infrequent feeding accumulates acid and selects acid-tolerant organisms.

The Landis et al. 2021 finding: geography matters less than expected. The largest citizen-science survey (500 starters, mostly from North America with some from Europe and Australasia) reframed folk wisdom: geography was a poor predictor (taxonomy did not correlate with geographic distance), and all the recorded process and household variables together explained less than 10% of community variation. S. cerevisiae dominated the yeasts (more than half of fungal reads) in 77% of samples; LAB plus acetic acid bacteria made up more than 97% of bacterial reads (L. plantarum and L. brevis the most common pair, 177 of 500). The cited surprise: acetic acid bacteria (distinct from acetic-acid-producing heterofermentative LAB) present at more than 1% in 147 starters, nearly absent from prior literature, and, in lab tests on a subset of about 40 starters, associated with slower rise (ρ = −0.51) and vinegary aromas (Landis et al., 2021).

pH and TTA. pH measures acid strength: a mature starter settles near pH 3.5–3.7 (McKenney et al., 2023), and ripe sourdoughs generally read about 3.5–4.2. TTA (total titratable acidity) measures total acid quantity: the milliliters of 0.1 N sodium hydroxide needed to bring 10 g of dough or sour to pH 8.5 (Viiard, 2014). TTA counts the acid load, buffering included, while pH turned out to be the better predictor of how sour a wheat sourdough bread tastes (Clément et al., 2020). Rye bakers track TTA to reach the acidification that controls amylase and structure; targets run from about 10–13 for a mild sour (Pistor, 2019) to 15–25 for strong rye sours (Viiard, 2014).

Stabilization and what acidity does to the bread. A new starter passes through a chaotic early succession (enterobacteria first, then Leuconostoc and Weissella) before acid-tolerant lactobacilli and their yeast partners lock in a stable low-pH climax, in a controlled study by about day 10 (McKenney et al., 2023); home starters often take one to two weeks. That acidity then: softens gluten (acid on its own weakens wheat dough (Wehrle et al., 1997), and low pH activates flour proteases (Gänzle, 2014), part of why over-fermented sourdough goes soupy); builds complex flavor (acids plus esters/alcohols/aldehydes); extends shelf life (low pH plus acetic acid are antifungal); cuts phytic acid (acid activates flour phytase, which degrades the phytic acid that binds iron, zinc and magnesium; the phytate drop is well supported, the improvement in people’s mineral status much less so) (Leenhardt et al., 2005); and slows staling. See Nutrition & Grain Science for the evidence on each.

Maintenance in practice. Keep a starter by discarding most and refreshing the rest at a chosen ratio. Stiff levains (~50–60% hydration) keep longer, taste more acetic; liquid levains (100%+) act faster and taste more lactic (Leo, n.d.-a). Retard at 37–41 °F (3–5 °C) to feed only weekly; dry (smear thin, dehydrate below about 104 °F (40 °C)) for shelf-stable, months-later revival.

Fermentation management for bread

Building/maintaining a levain. A levain is a bake-specific sourdough offshoot. Seed fresh flour and water with ripe starter: a 1:5:5 build (starter:flour:water) adds starter equal to 20% of the fresh flour’s weight, a 1:2:2 build 50%. Ferment it to peak ripeness (max leavening power, balanced acidity). A younger, sweeter levain gives milder flavor and stronger dough; a riper, more acidic levain gives more sour, weaker dough. The float test is unreliable (a stiff levain may not float when ready; a past-peak one may sink), so use time, volume rise, doming, and aroma instead (Leo, n.d.-a).

Reading bulk fermentation. Judged by the dough, not the clock: percentage rise (many rustic doughs shaped at ~30–75% increase depending on flour/schedule), the aliquot jar (a straight-sided sample jar that makes the rise easy to read), and dough feel (billowy, domed, jiggly, aerated, pulling from the container). Under-fermented gives dense, tight, gummy; over-fermented slackens, loses shaping strength, bakes flat.

Building strength for open crumb. Instead of intensive kneading, use stretch-and-folds and coil folds every 30–50 min in early bulk, and, for extra extensibility, lamination (stretching the dough thin on the bench and folding). These build and align gluten while preserving gas, and are among the ways to handle doughs at 80%+ hydration without collapse.

Pre-shape, bench rest, final shape. Divide, then loose pre-shape rounds (organize gluten), bench rest 15–30 min (relax), final shape with surface tension. Two-stage shaping lets a wet dough hold height.

Cold retard. Proofing (or bulk) at 37–43 °F (3–6 °C) for 12–48+ h develops flavor (acids and aroma compounds build over the long, slow ferment), improves scoring and oven spring (cold firm dough scores cleanly, springs high), and decouples the bake from the clock.

Strength vs extensibility. The whole game: balance elasticity (strength/spring, from tightly-bound gluten) against extensibility (willingness to stretch thin without tearing). Open crumb needs high extensibility with just enough strength to hold gas in thin walls (over-strong forces a tight uniform crumb; too weak collapses). Hydration/autolyse raise extensibility; folds, salt, lower hydration raise strength.

Shaping, scoring and baking

Shaping and the skin. All hearth shaping builds surface tension, a taut outer skin holding height and directing oven spring. Boule (dragged tight round), bâtard (folded/rolled seam-sealed log), baguette (progressively elongated cylinder). A slack skin spreads flat.

Proofing vessels. Floured banneton (wicks surface moisture for a scorable skin, imprints coil) or linen couche (supports baguette sides). Poke test: a gentle dent that springs back slowly and incompletely is ready; fast = under-proofed; not at all = over-proofed.

Scoring, grigne, ear. Scoring controls where the loaf expands: a designed cut opens under oven spring rather than tearing randomly (a “blowout”). A shallow (~30°) angled cut lifts a flap that dries into the ear; the bloomed cut face is the grigne.

The bake. Steam (injected, or trapped under a Dutch oven lid) keeps the crust moist and elastic so the loaf expands fully before setting, and gelatinizes surface starch for gloss/crackle. Oven spring (roughly the first 10–15 min): trapped gases expand, dissolved CO₂/ethanol vaporize, and yeast makes a final burst before dying off progressively from about 131 °F to 140 °F (55–60 °C) (BAKERpedia, n.d.-b). In dough, with less water to go round, starch gelatinizes from about 140 °F (60 °C) on to about 176 °F (80 °C) and beyond as gluten coagulates to set the crumb (Burt & Russell, 1983; Fessas & Schiraldi, 2000). Color comes from Maillard browning and, hotter still, caramelization, once the drying surface passes about 248 °F (120 °C) (Purlis & Salvadori, 2009). Lean hearth breads bake hot (about 450–480 °F (230–250 °C)); enriched cooler (about 340–390 °F (170–200 °C)) to avoid burning their sugars. Doneness: internal about 205–210 °F (96–99 °C) for lean loaves and about 190 °F (88 °C) for soft enriched ones (America’s Test Kitchen, n.d.-b; King Arthur Baking, 2017). Cooling finishes the bake: cutting hot gives gummy crumb; lean loaves cool 1–2 h, dense ryes at least a full day (Hamelman, 2004).

Crumb and quality

Open vs tight crumb. Open, irregular alveolation results from high hydration (thin extensible cell walls) plus adequate-not-excessive strength plus thorough fermentation plus gentle shaping/handling (preserving large gas pockets) and often cold retard. Tight even crumb (sandwich bread) comes from lower hydration, stronger/degassed dough, tighter shaping, pan support. Openness is a system property: hydration alone won’t deliver it if strength, fermentation, and handling don’t cooperate.

Common faults. Gummy/sticky crumb: under-baked; cut too hot; over-fermented (protease-degraded gluten); or unchecked rye amylase. Flat loaf/poor spring: over-proofed; weak gluten; slack shaping; insufficient steam. Dense/tight: under-fermented; under-hydrated; over-degassed; weak/dead leaven. Blowout: under-proofed and/or under-scored (spring with no designed exit). Pale crust: oven too cool; insufficient residual sugar (over-fermented or lean); too much steam held too long.

World breads: a survey

Tandoor/griddle breads of South/Central Asia. Naan (leavened, often yogurt/yeast-leavened enriched wheat) slapped onto a searing tandoor wall; roti/chapati (unleavened atta griddle breads); paratha (fat-laminated, flaky); puri (deep-fried, ballooning). Defining variable: heat source and whether leavened/enriched.

Pita and lavash. Pita: lean dough baked very hot (about 450–500 °F (230–260 °C)) so a steam burst inflates a hollow pocket (ThermoWorks, n.d.). Lavash: thin, large, lean, tandoor/griddle-baked, soft fresh and cracker-crisp dried.

**Injera (Ethiopia/Eritrea). A fermented batter flatbread traditionally of teff, which is naturally gluten-free, though many injera, especially outside Ethiopia, are cut with wheat or barley flour, so check before serving it to anyone with celiac disease (Allergic Living, n.d.); poured thin and cooked one side on a clay mitad; days of wild fermentation give sourness and a honeycomb of “eyes”, simultaneously bread, plate, and utensil.

Steamed breads of China. Mantou (plain) and baozi (filled) are steamed, not baked: soft, white, cakey crumb with no crust (no dry-heat browning); historically leavened with wheat sourdough/old-dough, now often yeast.

Nixtamalized breads of the Americas. The tortilla is built on nixtamal: maize cooked/steeped in alkaline (lime) solution, which loosens the hull, transforms flavor, and improves its nutritional value (it is credited with preventing pellagra). Masa is griddle-baked on a comal. Arepas (Colombia/Venezuela): thick maize cakes from pre-cooked maize flour.

Nordic rye and crispbreads. From dense moist sour whole-rye loaves to knäckebröd/crispbread: thin, dried, long-keeping rye flatbreads (the rye/acidification science in flat, shelf-stable form).

Laugengebäck. The pretzel family: lean low-hydration wheat dipped in food-grade lye for the mahogany, glossy, distinctive crust (see the Food safety note above).

Panettone (Italy). The most elaborate enriched natural-leaven bread: a tall, domed Milanese Christmas bread on a stiff sweet sourdough (lievito madre / pasta madre), enriched with butter, egg yolks, sugar, and candied fruit, developed over multiple days and builds. Its light, shreddy, long-keeping crumb depends on a rigorously mild (low-acetic) stiff starter; hung upside-down to cool so the delicate structure doesn’t collapse.

Contested and simplified claims