Drawn to its outside size
For temperature control around a starter jar
Brod & Taylor Sourdough HomeA small heating-and-cooling chamber for a jar, rather than a full dough bowl.
41 to 122°F, heats and cools8 × 10 in outside
Auf Deutsch · En français · En español
What is a sourdough starter?
A sourdough starter is a living culture of wild yeast and lactic acid bacteria in a paste of flour and water. The yeast makes the gas that raises bread; the bacteria make the acids that give sourdough its tang and help it keep. You keep it alive by feeding it fresh flour and water.
In short: flour and water, plus the wild yeast and bacteria that live on grain and in your kitchen. Feed it and it doubles in a few hours; that rising power is what you mix into dough instead of packaged yeast.
What lives in it
Wild yeasts eat the sugars in flour and give off carbon dioxide and alcohol. Lactic acid bacteria, far more numerous than the yeast, eat sugars too and make lactic and acetic acid. The acid keeps most other microbes out, which is why a healthy starter is safe to keep on the counter. Every starter has its own mix, shaped by the flour, the temperature and how it is fed.
Read when a starter is ready to see what that activity looks like in the jar.
Starter vs commercial yeast
You can bake with both: a little yeast in a sourdough speeds it up, and a spoonful of discard adds flavour to a yeasted dough. See starter, levain and other preferments.
| Sourdough starter | Instant or active dry yeast | |
|---|---|---|
| What it is | Wild yeast and bacteria in flour and water | One cultivated yeast strain, dried |
| Rise time | Slower: bulk about 3 to 5 hours at room temperature (King Arthur), longer when cool | Faster: often 1 to 2 hours |
| Flavour | Tangy, complex | Mild, wheaty |
| Keeping quality of the bread | Longer, thanks to the acid | Shorter |
| Upkeep | Regular feeding | None until opened |
Hydration: thick or runny
Most bakers keep a 100% hydration starter: equal weights of flour and water, about as thick as pancake batter. A stiff starter at 50 to 60% is more like dough and ferments more slowly. Both raise bread; see stiff vs liquid starter.
How a healthy starter looks and smells
Bubbly, domed or just past domed, and smelling pleasantly sour, yeasty or a little fruity. Strong vinegar or nail-polish smells mean it is hungry, not spoiled. Fuzzy spots (mold), pink or orange streaks (unwanted bacteria) or a smell that is not the usual sour or alcohol smell mean it has gone bad; see when to throw it out.
Questions bakers ask
Is a sourdough starter the same as yeast?
It contains yeast, but wild yeast together with lactic acid bacteria. Packaged yeast is a single cultivated strain.
Why is it called a starter?
Because a portion of it starts each batch of dough: you mix some into the flour and water, and keep the rest going.
Equipment for this job
Keep what you own when it does the job. These are the other exact models we profile.
Drawn to its outside size
OXO Good Grips 11 lb Stainless Steel Food Scale
For seeing the display past a wide bowl
OXO Good Grips 11 lb Stainless Steel Food ScaleA pull-out display helps keep the reading visible under larger containers.
11 lb (5.0 kg), reads in 1 g steps
Weck 743 Mold Jar, 3/4 L (set of 6)
For a starter you can see and scrape out
Weck 743 Mold Jar, 3/4 L (set of 6)A straight-sided 3/4 L glass jar with a glass lid; the wide mouth lets a spatula reach every corner.
28.7 fl oz, 3 7/8 in wide opening