Sourdough starter
A starter is a culture of wild yeast and lactic acid bacteria already present in the flour. You do not buy them — you create the conditions for them. The whole process takes about a week and demands only regularity: same hour, same ratio, same temperature.
Your own work in that: 0 min.
- Day 1 — starting 10 min
- Days 3–7 — feeding 20 min
- Maturing the culture 10050 min
Step by step
0 / 6 doneDay 1: mix flour and water
In a clean jar mix 50 g of wholegrain rye flour with 50 ml of lukewarm water into a thick paste. Cover loosely with muslin or a lid set on top and leave at 24–26°C. Mark the level with a rubber band.
Ingredients: 50 g rye flour · 50 ml water
TipWholegrain flour carries the most wild yeast on the bran. White rye takes several days longer to start.
Thick paste, loose cover — the gases must escape.Day 2: wait
After 24 hours you usually see a few bubbles and smell a faint sourness. Do not feed yet — for the first two days the culture is only getting going. If nothing is happening, move the jar somewhere warmer.
Ingredients: 50 g rye flour · 50 ml water
Days 3–7: feed daily
Every day at the same time discard half the starter and add 50 g of flour and 50 ml of water. Discarding sounds wasteful, but without it the starter keeps growing, each feed goes less far and the culture turns too sour and sluggish.
Ingredients: 250 g rye flour · 250 ml water
TipFeed at a fixed hour. Regularity matters more than precision on the scale.
Watch the bubbles and the smell
Around day 3 the starter often shoots up and then goes quiet for a day or two — that is normal, keep feeding. By the end of the week it should double in 6–8 hours after feeding and then fall. The smell shifts from unpleasant through vinegary to yoghurty and fruity. Grey liquid on top means it is hungry — feed more often.
Ingredients: 250 g rye flour · 250 ml water
A dense web of bubbles in different sizes — the culture is working.Do the float test
After 6–7 days drop a teaspoon of starter into a glass of water. If it floats, it is ready to bake with. A thick rye starter can be heavy and sink even when active, though — then what counts is whether it reliably doubles after feeding. If it sinks and barely rises, keep feeding for another 2–3 days and retest 4 hours after a feed.
Ingredients: 250 g rye flour · 250 ml water
Floating means the culture makes enough gas to lift bread.Switch to maintenance
Keep a finished starter in the fridge and feed it once a week. Before baking take it out, feed twice 12 hours apart and use it at peak activity.
Ingredients: 250 g rye flour · 250 ml water
Before you start
Tap water
Chlorine inhibits fermentation. Leave water out overnight in an open container or use boiled and cooled water.
Cold kitchen
Below 20°C a starter moves very slowly. Put the jar in a switched-off oven with the light on or beside a radiator — and check with a thermometer that it stays below 30°C.
Mould versus acid
Grey liquid and a vinegary smell are fine. Pink, orange or fuzzy patches are mould — throw everything out and start again.
