Slow CrumbGuides · Guide 1
Making and keeping a starter
How to grow a sourdough starter from flour and water, feed it, store it and tell when it is ready to bake with.
A starter is a stable culture of wild yeast and lactic acid bacteria living in a paste of flour and water. The yeast raises the bread; the bacteria give it its sour flavour. You only make one once.
What you need
- A clean jar of about 500 ml, with a loose lid
- Kitchen scales
- Wholemeal wheat or rye flour to begin, then white bread flour
- Water at about 26 °C (79 °F)
Day by day
| Day | What to do | What to expect |
|---|---|---|
| 1 | Mix 50 g wholemeal flour with 50 g water. Cover loosely and keep at 24–26 °C (75–79 °F). | Nothing visible. |
| 2–3 | Once a day, keep 50 g of the mix, discard the rest, and add 50 g flour and 50 g water. | Often a burst of bubbles and a strong smell. |
| 4–6 | Keep feeding daily. | Activity usually drops. This is normal: early bacteria die back as the mix turns acidic. |
| 7–14 | Feed daily. You can switch to white bread flour, or a mix. | A steady rise after each feed and a pleasantly sour, yeasty smell. |
The quiet spell around days 4–6 is where most people give up. Keep feeding.
When it is ready
A starter is ready to bake with when, for several days running, it doubles in volume within 4–8 hours of a feed at room temperature, with a domed top and bubbles throughout. A rubber band around the jar at the starting level makes the rise easy to read.
The “float test” (dropping a spoonful in water) is unreliable. Judge by the rise.
Feeding ratios
A feed is written as starter : flour : water, by weight.
| Ratio | Peaks in about (at 24 °C / 75 °F) | Use it for |
|---|---|---|
| 1:1:1 | 4–6 hours | A quick refresh |
| 1:2:2 | 6–8 hours | Everyday feeding |
| 1:5:5 | 10–12 hours | An overnight feed |
Cooler rooms slow all of these down; warmer rooms speed them up.
Storing it
- On the counter: feed once or twice a day. Best if you bake several times a week.
- In the fridge: feed it, leave it out for an hour or two, then refrigerate. Feed about once a week. Before baking, take it out and give it one or two feeds until it doubles on schedule again.
Common questions
- Grey or brown liquid on top. This is “hooch”, a sign the starter is hungry. Stir it in or pour it off, then feed.
- It smells like nail-polish remover. Also hunger. Feed more often, or at a higher ratio.
- Fuzzy mould, or pink or orange streaks. Discard the starter, wash the jar and start again.
- Tap water. Usually fine. If a new starter struggles, try filtered water, or tap water left to stand for a few hours.