Sourdough is bread made by fermenting flour and water with a living culture of wild yeast and friendly bacteria, rather than relying only on commercial baker’s yeast.
The quick answer
Sourdough is both a method and a style of bread. A sourdough starter ferments the dough, helping it rise while developing flavour, structure and acidity. The process is slower than a typical yeasted loaf, but it is not complicated once you understand the basic rhythm.
What makes bread “sourdough”?
The defining feature is the fermentation. Instead of adding a packet of baker’s yeast as the main raising agent, you add an active sourdough starter. That starter contains a stable community of naturally occurring yeasts and lactic acid bacteria.
Once mixed into the dough, the yeasts produce carbon dioxide. The dough’s gluten network traps that gas and the loaf expands. At the same time, the bacteria produce organic acids and other flavour compounds. These give sourdough its character and influence how the dough develops.
A sourdough loaf does not have to taste sharply sour. Flavour can range from mild, creamy and wheaty to noticeably tangy. Temperature, starter condition, flour choice and fermentation time all affect the result.
Bake slower
Sourdough works on a living timetable. A recipe gives you a useful plan, but the dough tells you when each stage is complete. Learning to notice rise, bubbles, strength and texture is more reliable than following the clock alone.
The four basic ingredients
- Flour: supplies starches, proteins and minerals. Bread flour is a forgiving place to begin.
- Water: hydrates the flour, supports fermentation and allows gluten to develop.
- Salt: adds flavour, strengthens the dough and helps regulate fermentation.
- Sourdough starter: provides the yeasts and bacteria that ferment and raise the dough.
That is enough to make a classic loaf. Seeds, wholegrains, malt, oils, fruit and other ingredients can come later. Starting simply makes it easier to understand what the dough is doing.
How sourdough bread is made
- Refresh the starter. Feed it with flour and water and wait until it is active.
- Mix the dough. Combine flour, water, starter and salt.
- Develop strength. Folds or gentle handling organise the gluten network.
- Bulk ferment. Leave the dough to rise and develop gas, strength and flavour.
- Shape and proof. Shape the loaf, then allow it to complete its final fermentation, often in the fridge.
- Score and bake. Cut the surface so the loaf can expand in a controlled way, then bake until deeply coloured.
Why does sourdough take longer?
A sourdough starter normally ferments dough more slowly than commercial yeast. A typical loaf may move from mixing to baking over one or two days, although much of that time is hands-off. The exact schedule depends on temperature, starter activity and the quantity of starter used.
Slower does not mean you must stay beside the dough all day. Most stages can fit around work, sleep and family life. The useful skill is learning how temperature speeds fermentation up or slows it down.
Common mistake: treating time as a fixed instruction
If a recipe says “bulk ferment for five hours”, that is an estimate for particular conditions. A cool kitchen may need longer; a warm dough may move much faster. Look for a smoother, aerated dough with visible bubbles and an appropriate increase in volume.
Is sourdough always healthier?
Sourdough fermentation changes the dough, but “healthier” is too broad to promise for every person or loaf. The result depends on the flour, recipe, fermentation and the rest of your diet. Some people find a well-fermented loaf enjoyable and easier to eat, but sourdough is not a treatment for a medical condition.
Most sourdough made with wheat, rye or barley still contains gluten. It is not suitable for someone with coeliac disease unless it is specifically produced and certified as gluten-free.
What does good sourdough look and taste like?
There is no single correct appearance. A good loaf might have a light, open crumb or a closer, softer texture. It may be round, oval or baked in a tin. What matters is that it is properly fermented and baked for the style you intended.
- A well-coloured crust with a clean, toasted aroma.
- A crumb that is set rather than gummy.
- A flavour that balances grain, fermentation and salt.
- A texture appropriate to the loaf—not simply the largest possible holes.
Your first practical goal
Aim for a loaf that ferments predictably, holds its shape and tastes good. Consistency teaches you more than chasing a dramatic open crumb on your first attempt.
Sourdough questions beginners often ask
Is sourdough just ordinary bread left to go sour?
No. It is controlled fermentation using a maintained starter. Pleasant acidity is one possible flavour, not a sign that the dough has spoiled.
Does all sourdough contain only three ingredients?
No. A basic loaf contains flour, water and salt, plus starter made from flour and water. Bakers may add grains, seeds, fats or sweeteners. Some commercial breads also combine sourdough culture with baker’s yeast, so check the ingredients if the production method matters to you.
Do I need special equipment?
No. A bowl, scales, a jar, a scraper and a suitable baking vessel are enough to begin. A banneton and scoring blade are useful, but they are not what makes the bread sourdough.
Can I make mild sourdough?
Yes. Use a healthy starter near its peak, avoid excessively long warm fermentation and begin with mostly white bread flour. A cold proof can add flavour without automatically making the loaf sharply acidic.
Is sourdough difficult?
The first few loaves involve new observations, but the method becomes repetitive quickly. Most problems come from starter strength, temperature or fermentation—not from a lack of complicated technique.
Begin with a starter that is ready to use
Our sourdough starter kits bring the culture, tools and guidance together, so you can spend less time assembling supplies and more time learning how the dough behaves.
Continue learning
Next, learn what a sourdough starter is, how it stays alive and why its condition affects every loaf you bake.
A good way to learn
Focus on repeatability before optimisation. Use one straightforward recipe, keep notes on temperature and timings, and change only one thing on the next bake. You will learn faster from three comparable loaves than from three completely different methods.