Hub 02 · Sourdough Starter
Sourdough starter troubleshooting chart
Find the symptom in the table, read the likely cause, apply the fix. Almost every entry resolves to temperature, feeding schedule, or patience.
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Almost every starter problem is one of four things: the kitchen is cold, the feeding ratio is off, it needs more time, or it is not a problem at all. The table sorts the symptom you can see from the cause you cannot.
| What you see | Likely cause | Fix |
|---|---|---|
| No activity at all, days 1-3 | Normal. Nothing has colonized it yet | Keep feeding on schedule. Do not intervene |
| Bubbled early, then went quiet around days 4-8 | Normal. The early bacteria died back and the real culture is establishing | Keep feeding and keep it warm. This is where most starters get binned |
| Rises slowly or not at all after two weeks | Cold kitchen, most often | Move it somewhere warmer and give it more time before changing anything else |
| Dark liquid on top (hooch) | Hungry. It has run out of food | Pour it off or stir it in, then feed more often or at a higher ratio |
| Smells of acetone or nail polish remover | Very hungry, same cause as hooch | Feed more frequently, and increase the flour and water relative to the starter |
| Smells strongly sour or vinegary | Long gaps between feeds, or a warm room | Feed more often. Sour is a flavor outcome, not a fault |
| Rises and falls before you can use it | Faster than your schedule - usually a warm kitchen | Use it sooner after feeding, or feed at a higher ratio to slow it down |
| Thin, runny, will not hold bubbles | Too much water for the flour | Feed with equal weights of flour and water, measured on a scale |
| Thick, dense, sluggish | Too little water, or a very high-protein flour | Feed with equal weights and check the scale is reading in grams |
| A thin white film on the surface | Usually kahm yeast. Harmless, but a sign it has been left too long | Scrape it off, feed, and resume a regular schedule |
| Fuzzy growth, raised, any color | Mold | Throw the whole thing out, jar contents and all. Do not scrape and continue |
| Pink, orange or red streaks | Contamination | Throw it out. This is the one color that is never ambiguous |
The four causes behind almost every row
- Temperature. A starter in a 64F kitchen behaves like a different organism from the same starter at 76F. Cold is the single most common explanation for a starter that looks dead, and the fix is free.
- Feeding ratio. Feeding a large amount of starter a small amount of flour keeps it permanently hungry. More flour and water relative to the existing starter buys it more time between feeds.
- Time. Two weeks is normal to establish. Three is not alarming in winter.
- Measurement. Volume measures of flour vary by up to a third depending on how the cup is filled. This is why every entry in the table that mentions consistency ends with a scale.
Hooch, in more detail
The gray or brown liquid that collects on top is alcohol produced by a hungry culture. It is not spoilage and it is not dangerous. Pouring it off makes a milder starter; stirring it in makes a sharper one. Either way it is a message about the feeding schedule, and the schedule is the thing to change.
A starter kept in the refrigerator will develop hooch between weekly feeds and that is entirely expected — the routine for fridge-kept starters is in feeding and storing a sourdough starter.
Rise, and how to actually measure it
“It doubled” is the standard test and most people estimate it badly. Put a rubber band or a silicone band around the jar at the level of the starter immediately after feeding. Then doubling is something you read off the jar rather than something you remember.
A straight-sided jar makes this reliable, which is one of the two reasons the jar shape matters at all — the other is headspace.
Telling a ready starter from a merely active one
Bubbles are not readiness. A starter is ready to bake with at its peak — risen to its highest point and not yet falling back — which is usually a window of an hour or two, several hours after a feed.
Two checks worth doing. The band on the jar tells you whether it has doubled and whether it has started to sink again. The float test — dropping a small spoonful into water to see whether it floats — is a rough guide to how much gas it is holding; it is a useful signal rather than a verdict, and a stiff starter can fail it while still baking perfectly well.
If your starter is reliably doubling but your loaves are dense, the timing of when you use it is the first thing to examine, before anything in the table above.
When the chart says the starter is fine and the bread still fails
A healthy starter that doubles reliably will make bread. If the loaves are dense and the starter is behaving, the problem has moved downstream to proofing, shaping or baking rather than the culture. Underproofing in a cold kitchen is the usual answer, and it is the same temperature story from the top of this page.
If the starter is genuinely not rising rather than rising slowly, the causes are ordered by likelihood in why your sourdough starter is not rising.
Frequently asked
Questions
+What does it mean when my starter has liquid on top?
That is hooch, the alcohol a hungry starter produces. It is harmless. Pour it off for a milder starter or stir it in for a sharper one, then feed more often or at a higher ratio.
+Why does my sourdough starter smell like nail polish remover?
An acetone smell means the culture is very hungry. Feed it more frequently, and increase the amount of flour and water relative to the starter you keep.
+When should I throw out my sourdough starter?
Fuzzy raised growth of any color, pink or orange streaks, or a genuinely foul smell. Those three mean discard everything, including the jar contents. Sour smells, hooch and slow rises are all normal.
+Is a white film on my starter mold?
Usually not. A thin, flat white film is typically kahm yeast, which is harmless and signals neglect rather than danger. Mold is fuzzy and raised and stands above the surface.
+How long should a starter take to double?
An established starter in a warm kitchen usually doubles in four to eight hours after feeding. Longer than that is normal in a cold room, and the fix is warmth rather than more flour.
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