Sourdough Artisan Baking

This deck walks you through the essentials of artisan sourdough baking, starting with the basics of what sourdough actually is and how a starter works. You'll explore the science behind the craft, including the yeasts and bacteria that drive fermentation, what a SCOBY is, and how sourdough differs from bread made with commercial yeast. The cards also cover key stages and techniques in the baking process, from autolyse and fermentolyse to bulk fermentation, proofing, and hydration.

It's a great fit if you're new to sourdough and want to build a solid foundation of terminology before you start baking, or if you've been baking for a while and want to better understand the "why" behind the steps you follow. Bakers, food science enthusiasts, and anyone curious about traditional fermentation will find something useful here.

Because the deck is packed with vocabulary and definitions, regular review will help the terms stick. Try spacing your study sessions over several days rather than cramming, and whenever you can, connect a card to a real step in your own baking process, like feeding your starter or shaping a loaf. That way, each flashcard reinforces both the word and the hands-on skill behind it.

Sourdough is bread leavened not by packaged commercial yeast but by a wild, living culture of yeast and bacteria that lives in flour and water. This culture, called a sourdough starter, is a symbiotic ecosystem often referred to as a SCOBY, or Symbiotic Culture Of Bacteria and Yeast. The yeasts found in sourdough belong to various species, most commonly Saccharomyces and Kazachstania, while the bacteria are usually different kinds of lactobacilli, with Lactobacillus sanfranciscensis being especially common in traditional sourdough cultures. Together, these microorganisms transform a simple mixture of flour and water into bread that is flavorful, naturally leavened, and shaped by the activity of a wild microbial community.

The yeast and bacteria each play distinct but complementary roles. The yeast consumes sugars in the dough and produces carbon dioxide gas, which leavens the bread by inflating bubbles that lift the dough; sourdough yeasts also contribute volatile aromatic compounds that build complex flavor. The bacteria produce lactic and acetic acids, which give sourdough its characteristic tang, help preserve the bread naturally, and contribute to the long keeping quality that has historically made sourdough valuable. The balance between yeast and bacterial activity shapes the bread's flavor profile, and bakers learn to read this balance through practice. Because sourdough relies on wild fermentation rather than a packet of dried yeast, fermentation times are considerably longer than for conventional bread, typically ranging from four to twenty-four hours or more depending on temperature, hydration, and recipe.

The fundamental difference between sourdough and conventional yeasted bread comes down to the source of the leavening. Yeasted bread uses a single species of commercial yeast added in measured amounts, while sourdough uses a diverse, unpredictable community of wild microbes that must be fed, kept alive, and allowed to ferment over time. This wild fermentation is the foundation of every technique that follows, from starter care to shaping to baking.

A sourdough starter is a living culture that requires regular attention. To keep it healthy, you mix fresh flour and water into the starter on a regular schedule in a process called feeding. The most common feed ratio is one part starter, one part flour, and one part water by weight, often written as 1:1:1, though other ratios are used to control fermentation speed and flavor. A starter is at peak activity when it has roughly doubled in volume and is full of bubbles; this is the point at which it has the most leavening power and is most useful in a dough. A simple way to gauge readiness is the float test: a small spoonful of starter dropped into a bowl of water will float when it has trapped enough gas to leaven bread. Typical sourdough recipes call for ten to twenty percent of total flour weight in active starter, though this varies with hydration, temperature, and desired fermentation time.

Every feeding produces more starter than you can usually use, which is why bakers talk about discard. Discard is simply the portion removed before feeding, and it is not wasted; it can be used in pancakes, crackers, waffles, and many other recipes. With time, bakers learn to recognize the warning signs of a struggling starter. A starter that is lazy or dormant may need several feedings to revive. Sometimes a dark liquid forms on top of a hungry starter; this is hooch, an alcoholic by-product of yeast metabolism that smells sharp and should be poured off before the next feeding. A stinky starter often signals the same condition and is generally corrected by a thorough feeding. The most common reasons starters fail are underfeeding, inconsistent temperature, and contamination from dirty utensils, all of which are easy to prevent with a little routine care.

One of the great advantages of a sourdough starter is its longevity. A starter can rest in the refrigerator for weeks or even months between feedings if kept cool, and many home bakers establish a weekly baking rhythm that requires feeding only once a week. There is also flexibility in how a starter is built and used. Bakers often maintain a split starter, keeping one culture of white flour and one of rye, since rye is naturally rich in microbes and ferments very actively. A stiff starter, fed at fifty to sixty percent hydration, ferments more slowly and produces more lactic flavor. To accelerate a sluggish starter, a small amount of rye flour added to the next feed can give it a noticeable boost. Building a new starter from scratch typically takes five to fourteen days of daily flour-and-water feedings, with the baker watching for the first signs of bubbles and rise.

The single most important variable in a sourdough recipe is hydration, which is the ratio of water to flour by weight expressed as a percentage. A standard loaf is built around sixty-five to eighty percent hydration, with higher hydration generally producing a more open crumb but also being more difficult to handle. Hydration is one of many ingredient relationships that bakers describe using baker's percentage, a system in which every ingredient is expressed as a percentage of total flour weight. In this system, flour is always one hundred percent, and water, salt, starter, and any inclusions are calculated relative to it. Salt typically represents about two percent of flour weight and plays several roles: it strengthens gluten, slows yeast activity to regulate fermentation, and adds flavor.

Flour choice dramatically shapes the character of the bread. Bread flour, with twelve to fourteen percent protein, builds strong gluten and tolerates long fermentation well. All-purpose flour, at ten to twelve percent protein, is versatile and works in many recipes. Whole wheat flour is milled from the entire wheat kernel and includes the bran and germ, which produce a denser crumb, more complex flavor, and noticeably faster fermentation because the bran carries natural enzymes and minerals. Higher-extraction flour sits between whole wheat and white flour, with most of the bran sifted out, while Type 00 is a finely milled Italian flour used especially for pizza and pasta whose protein content varies. Beyond wheat, rye flour is a different grain with much less gluten and requires different handling; spelt and einkorn are ancient wheats with distinctive flavors and weaker gluten structures. Fresh-milled and stone-milled flours preserve more enzymes, oils, and nutrients than heavily processed commercial flours, and many bakers are increasingly interested in heritage wheat varieties and the field-to-loaf movement that traces grain from farm to bread.

Specialty ingredients also enter the conversation. Malt, in diastatic form, provides active enzymes that break starch into sugars that feed the yeast; non-diastatic malt simply adds flavor and color without active enzymes. Fats such as olive oil tenderize the crumb and add flavor, especially in breads like focaccia and ciabatta. Seeds and grains add texture and nutrition, but should be soaked beforehand so they do not draw moisture out of the dough during baking. Buckwheat is a pseudo-grain, technically not wheat, that is naturally gluten-free and useful in alternative baking. A few ingredients, including vital wheat gluten, vitamin C, and commercial dough conditioners, are sometimes used to strengthen dough, but they are not part of traditional artisan sourdough practice.

Wheat flour contains two proteins, glutenin and gliadin, that combine with water to form gluten, the elastic network responsible for trapping gas and giving bread its structure. Gluten development happens through hydration, mixing, and time, and a baker's job is to build that network in the gentlest, most effective way. The windowpane test is a way to check whether the dough has been developed enough: when a small piece is stretched thin, it should form a translucent membrane without tearing. Many artisan bakers do very little traditional kneading, instead relying on time and gentle folding techniques.

One of the most important early steps is the autolyse, a brief rest of flour and water before adding salt and starter. This rest fully hydrates the flour, allowing gluten to begin forming on its own and easing the work of mixing. A related technique called fermentolyse, also called fermentolysis, includes the starter from the beginning of the rest, which saves time and supports gluten development. After mixing, gluten continues to build through a series of folds during bulk fermentation. The stretch and fold is the gentlest option and is repeated several times at intervals. The coil fold is similar but especially useful for high-hydration doughs because it lifts and coils the dough without deflating it. The slap and fold, popularized by Richard Bertinet, is a more aggressive technique that develops gluten quickly through rhythm and impact. Methods like the no-knead approach from Mark Bittman, the Tartine method of Chad Robertson, and the approach in Ken Forkish's Flour Water Salt Yeast all build on these ideas with different philosophies about hydration, time, and shaping.

Bulk fermentation is the first rise after mixing, before the dough is shaped. Its length depends on temperature and starter activity, and the baker's goal is to manage it so that the dough has built both structure and flavor without over- or under-fermenting. Desired dough temperature, often abbreviated DDT and typically targeted at seventy-five to eighty degrees Fahrenheit, is a useful concept because it predicts fermentation speed: warmer dough ferments faster, cooler dough slower. The water temperature required to hit the DDT is calculated from the ambient room temperature and a friction factor that accounts for heat generated during mixing. A cold retard, in which bulk-fermented or shaped dough is held in the refrigerator for eight to forty-eight hours or even longer, slows fermentation dramatically and develops complex, deeper flavor while letting the baker bake on their own schedule. Strong, well-developed dough has what bakers call fermentation tolerance, meaning the ability to handle long fermentation without collapsing; higher-protein flours, properly developed gluten, and adequate salt all contribute to this resilience, while higher altitudes generally cause dough to rise faster and may require small adjustments.

After bulk fermentation, the dough goes through a series of steps to prepare it for the oven. It is first divided or given a loose preliminary shape called a preshape, then left for a short bench rest of fifteen to thirty minutes so that the gluten can relax before final shaping. Final shaping is where surface tension is built, often through a rolling technique in which the dough is folded toward itself, with the seam pinched closed by stitching so that the loaf holds its shape and rises upward rather than spreading outward. This shaping with structure is what gives a tall, well-risen loaf. The seam side becomes the bottom of the loaf because it is the weakest point.

Several tools support these tasks. A bench scraper is a flat, stiff tool for lifting and cutting dough on the counter, while a flexible dough scraper is better for handling sticky dough. Bench flour is dusted on surfaces and on the dough to prevent sticking, though it is used sparingly so as not to disrupt the dough's hydration. Proofing baskets called bannetons, traditionally made of rattan and lined with linen, give the loaf its shape and leave characteristic ring patterns on the crust; a couche is a heavy linen cloth used for proofing long loaves like baguettes and batards. Once the loaf is shaped and proofed, it is scored with a lame, a razor blade tool, just before baking.

Scoring serves both function and aesthetics. The cuts control where the dough expands during oven spring and prevent it from tearing unpredictably. A properly scored loaf produces an ear, a raised flap of crust, when the cut is shallow and made at about twenty to thirty degrees to the surface; deeper cuts open more dramatically and shallow cuts produce gentler ears, while decorative scoring patterns can be both functional and beautiful. The second rise, or final proof, develops flavor and structure between mixing and baking. It can happen at room temperature for a faster result or in the refrigerator for slower fermentation and more developed flavor. The dough is judged by the poke test: pressed gently with a floured finger, properly proofed dough springs back slowly and leaves a slight indentation, while under-proofed dough springs back quickly and over-proofed dough collapses and never recovers good oven spring.

The first minutes in the oven are the most dramatic part of the bread's life. The loaf experiences oven spring, a rapid final rise driven by the expansion of trapped gases as the dough heats. To allow this rise to happen fully, the crust must stay soft long enough to stretch, and that is the role of steam. Steam in the early phase of baking delays crust formation so that the loaf can expand to its maximum volume, and a heavy lidded pot called a Dutch oven is the most popular home way to create this steamy enclosed environment without specialty equipment. Trapping steam around the loaf is what produces a crackling, sometimes blistered crust with strong oven spring.

As baking continues, two important browning reactions take over. The Maillard reaction occurs between amino acids and reducing sugars at temperatures above about 140 degrees Celsius, producing deep browning and the complex savory flavors characteristic of artisan crust. Caramelization, the browning of sugars, happens at higher temperatures and contributes additional color and flavor. Together, these reactions build the thick, flavorful crust that defines sourdough. Typical sourdough is baked at 450 to 500 degrees Fahrenheit (230 to 260 degrees Celsius) for thirty to fifty minutes, depending on loaf size and oven, and a finished loaf generally weighs 750 to 1000 grams for a standard boule or batard.

Doneness is checked in several ways. The most reliable is internal temperature: a finished loaf reads 200 to 210 degrees Fahrenheit, with 205 being a common target. Many bakers also tap the bottom of the loaf; a properly baked loaf sounds hollow. Once out of the oven, the loaf must cool on a rack for at least an hour before being cut, both because the crumb continues to set as moisture redistributes and because slicing too early produces a gummy interior. Cooling on a rack is essential so that steam can escape; otherwise the bottom becomes soggy. While a perfect ear is a celebrated mark of skill, ear perfectionism is only one sign of a good loaf and not the only measure of success.

Every baker encounters problems, and learning to read the bread is part of the craft. A flat loaf is usually under-fermented, poorly shaped, or made with a weak starter. A gummy interior is most often caused by under-baking or by cutting the loaf too soon. Dense bread can result from a weak starter, low hydration, or insufficient gluten development. Overly sour bread can be moderated by reducing fermentation time, lowering hydration, or slightly increasing the salt; remember that acetic acid brings a vinegar-like sharpness produced at cooler temperatures, while lactic acid brings a softer yogurt-like tang produced at warmer temperatures. A blown-out loaf, with ragged tears where it burst during baking, is almost always under-proofed, meaning the dough had too much energy left when it entered the oven. Over-proofed dough cannot be fully rescued, but reshaping and baking it quickly will still yield an edible, if denser, loaf. The crumb itself carries information: open crumb with large irregular holes signals good hydration and fermentation, tight crumb with small even holes is what sandwich bakers prefer, and a wet interior that feels uncooked is a sign of under-baking.

Sourdough encompasses a wide variety of loaves. The simplest shapes are the round boule, the oval batard (which sits between a baguette and a boule), and the large rustic miche, often made with whole grains. Beyond these, sourdough takes many forms: Italian focaccia with olive oil and toppings, high-hydration ciabatta with open crumb, classic baguette, soft pain de mie in a Pullman pan, enriched French brioche, braided Jewish challah, leavened South Asian naan, pocket-forming pita, and sourdough pizza baked on a stone or baking steel at the highest possible home oven temperature, often 500 to 550 degrees Fahrenheit. Neapolitan pizza is thin and baked at very high heat with a soft center, while New York style is hand-tossed and firmer. Bakers also work with pre-ferments other than sourdough: poolish is a wet French pre-ferment, biga is a stiff Italian one, and pâte fermentée, or old dough, is leftover dough added to a new batch for flavor; these use commercial yeast rather than wild cultures. Lean doughs contain only flour, water, salt, and leavening, while enriched doughs add significant fat, sugar, eggs, or dairy. Sourdough made with rye produces distinctive loaves, from light and dark rye varieties to dense German pumpernickel baked at low temperature for hours, often seeded with caraway, fennel, or anise. Gluten-free sourdough is possible using non-wheat flours but requires different techniques and patience, and buckwheat is a useful pseudo-grain for such bakes. Sourdough also differs from quick bread, which uses baking soda or powder for leavening rather than fermentation.

Beyond recipes and techniques, sourdough is also a culture and a way of working. Sourdough is part of a broader fermentation cooking movement that includes kimchi, yogurt, kombucha, and beer, all of which rely on microbial activity. The long fermentation of sourdough is also believed by many to aid digestion by reducing phytic acid, and ongoing research explores whether some celiac sufferers tolerate sourdough better, though it is not considered safe for them. Storage is simple: bread wrapped in paper or cloth stays fresh for two to four days at room temperature, while plastic softens the crust. Sliced and frozen bread thaws quickly and toasts well. Stale bread becomes breadcrumbs, croutons, panzanella, French toast, panades, and soup thickener. To bake well, weigh ingredients on a kitchen scale with one-gram precision, because weight is far more reproducible than volume. Keep notes on each bake to accelerate learning. Settle into a weekly rhythm of one to three loaves. Engage with the wider community of bakers through guilds, forums, classes, community supported bakeries, and open-source recipe sharing. The baker's craft is sometimes called a long apprenticeship, developed over months and years of patient practice, working with living cultures and small choices that yield dramatic results. The joy of sourdough lies in this slow connection with an ancient craft, the satisfaction of sharing bread, and the sensory pleasure of working with one's hands.