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
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What is wrong with my sourdough starter?
Most starters that look bad are hungry, cold or past their peak, and a few warm feeds put them right: a mature starter is hard to kill, King Arthur says.
Throw it out: fuzzy spots of any colour, pink or orange streaks, a smell other than sour or alcohol. Feed it: liquid on top, a nail-polish or vinegar smell, a dry skin, a slow rise after the fridge. Give it time: a quiet spell on days 3 to 5 of a new starter.
Check your starter
Answer a question or two to see what is going on and what to do next.
What is going on with your starter?
How old is your starter?
Count from the day you first mixed its flour and water.
Which day is it?
What has changed since it last rose well?
What does it do in the hours after a feed?
Put a rubber band at the level right after feeding, then compare.
What do you see?
What does it smell like?
When is it runny?
How long since its last feed?
What happened to it?
What did you get?
Look at it now. Which is closest?
Nothing is wrong
Too early to tell
On day 1 little happens. A rise on day 2 is common, and it is mostly bacteria that thrive before the jar turns acidic, not yet the yeast that will raise bread.
Do this now
- Keep 50 g, add 50 g flour and 50 g room-temperature water once a day.
- Keep the jar somewhere warm, ideally 75 to 78°F (24 to 26°C).
Look again in 24 hours.
What to expect: A quiet spell on days 3 and 4. It is normal, and it passes.
More on this:Making a starter, day by day
Nothing is wrong
Normal: the quiet spell
The day-2 rise was mostly bacteria. As the starter turns acidic they die back, and the jar goes quiet until the yeast takes over. A sharp or cheesy smell now belongs to the same phase.
Do this now
- Keep feeding once a day: keep 50 g, add 50 g flour and 50 g water.
- Put some whole wheat or rye in the feed and keep the jar warm.
Look again in 24 hours.
What to expect: Bubbles come back and it rises a little more each day, often from day 5.
More on this:Making a starter, day by day
Easy to fix
Young and slow: warmth and two feeds a day
A starter this young is still building up its yeast, and a cool kitchen adds days. King Arthur says a new starter could take 7 days or less, or up to a couple of weeks.
Do this now
- Keep it at 75 to 78°F (24 to 26°C), or feed it with lukewarm water.
- Feed twice a day, about 12 hours apart, once it rises at all.
- Add a spoonful of whole wheat or rye flour to each feed.
Look again in 12 hours.
What to expect: It is ready to bake with when it doubles within about 6 to 8 hours of a feed, feed after feed.
More on this:Making a starter, day by dayThe signs it is ready
Easy to fix
Stuck: check the warmth, the flour and the water
There is no deadline, but past two weeks something is usually holding it back: a kitchen below about 70°F (21°C), only bleached white flour in the feed, or heavily chlorinated tap water, which can slow a young starter.
Do this now
- Keep it at 75 to 78°F (24 to 26°C) and feed it twice a day.
- Feed unbleached flour with 10 to 20% whole wheat or rye.
- Use filtered water, or tap water left out overnight. Chloramine does not leave that way; a carbon filter removes it.
Look again in 12 hours.
What to expect: Most get stronger through week 3. Fuzzy mold, pink or orange streaks, or a smell other than sour or alcohol mean throw it out and start again.
More on this:Which water to useWhy a starter stays weak
Easy to fix
New home: feed it the way it was fed
A starter that has travelled or sat in a fridge needs two or three warm feeds before it rises well in your kitchen.
Do this now
- Ask how it was fed: which flour, what ratio, how often.
- Feed it the same way twice a day at 75 to 78°F (24 to 26°C), in a clean jar with the level marked.
Look again in 12 hours.
What to expect: Once it doubles within 4 to 8 hours, bake with it, and dry a spoonful as a backup.
More on this:First steps with a gifted starterDrying a backup
Easy to fix
Cold from the fridge: one or two warm feeds
At about 38°F (3°C) the yeast and bacteria barely work, and the acid that built up while it waited slows it further. A feed or two at room temperature gives it back its rising power.
Do this now
- Feed it 1:1:1, for example 30 g starter, 30 g flour and 30 g water.
- Leave it to rise at 75 to 78°F (24 to 26°C). If it is slow, feed it again.
Look again in 8 hours.
What to expect: If it doubles within about 6 to 8 hours, it is ready to build your levain. After a few weeks in the fridge, allow 2 to 4 days of feeds.
More on this:Fridge care and waking it upWork out the levain
Nothing is wrong
Normal: it is getting used to the new flour
A new flour changes the pace for a feed or two: whole grain usually brings the peak sooner, white flour later. Rye makes a thick paste that rises less visibly, so judge it by its bubbles and domed top more than its height.
Do this now
- Keep the same ratio and feed the new flour two or three times in a row.
Look again in 12 hours.
What to expect: Once it doubles reliably again, it has adjusted.
More on this:Changing a starter’s flour
Easy to fix
Slow: almost always a cool kitchen
Temperature sets the pace. At 75 to 78°F (24 to 26°C) a 1:1:1 feed usually peaks in 4 to 8 hours; in a cool kitchen it can take most of a day. A starter that doubles but needs more than 12 hours is alive, just not strong yet.
No warm spot? An oven with only its light on can work. Check it with a thermometer first, and tape a note to the door: switching the oven on with the jar inside kills the starter (King Arthur).
Do this now
- Find a spot at 75 to 78°F, or feed it with lukewarm water, never above about 100°F (38°C).
- Feed twice a day, about 12 hours apart, for a few days.
- Put 10 to 20% whole wheat or rye in the feed.
Look again in 12 hours.
What to expect: When it doubles within 6 to 8 hours of a feed, it is strong enough to raise bread.
More on this:Fixing a weak starterA jar and a warm spot
Easy to fix
Bubbles but no rise: often too runny
The bubbles show it is alive. A starter that has ended up too wet may bubble without climbing the jar the way you expect; King Arthur says that does no lasting harm, and a little more flour corrects it. A thick rye starter also rises less visibly.
Do this now
- Weigh the next feeds: equal weights of flour and water, or a little more flour for a feed or two.
- Keep it warm and feed twice a day.
- With a rye starter, judge by bubbles all through and a domed top, not by height.
Look again in 12 hours.
What to expect: Look for the level climbing past the rubber band within a feed or two.
More on this:Thick or runny starterRye and whole wheat starters
Easy to fix
It did rise: you missed the peak
Streaks on the glass above the starter show how high it climbed before it ran out of food and fell back. A warm kitchen or a small feed brings the peak early, sometimes overnight. A fallen starter is also thinner than it was at its peak.
Do this now
- Feed it again and put a rubber band at the new level.
- Check it every couple of hours, or feed at a higher ratio, 1:2:2 or 1:5:5, so it peaks later.
Look again in 4 hours.
What to expect: Use it at or just before the peak: doubled, domed and bubbly.
More on this:The rise, the peak and the fallRatios that move the peak
Easy to fix
No activity: underfed or kept long past its peak
An established starter that does nothing after a feed has usually gone too long between feeds, or been fed long after its peak, and its acid has built up. It is very rarely dead: King Arthur calls a mature starter pretty hard to kill.
Do this now
- Take 50 g from the middle into a clean jar.
- Feed it 50 g flour and 50 g warm, not hot, water.
- Keep it at 75 to 78°F (24 to 26°C) and repeat every 12 hours.
Look again in 12 hours.
What to expect: Any rise or bubbles after the first two warm feeds means it is alive. Keep going until it doubles within 4 to 8 hours.
More on this:Reviving a starterWhy a starter stays weak
Easy to fix
Hooch: hungry, not spoiled
The liquid is mostly water and alcohol from fermentation, and it collects when the starter has run out of food. Grey, brown or even black, it is harmless; it darkens the longer it sits (King Arthur).
Do this now
- Pour it off for a milder starter, or stir it in for more tang.
- Discard down to your usual amount and feed.
What to expect: If it shows up every day on the counter, feed more often or at a higher ratio.
More on this:Hooch explained
Throw it out
Fuzzy spots are mold
Raised, fuzzy spots of any colour are mold. Its threads can reach beyond what you see, so scraping it off does not save the starter.
Do this now
- Throw the starter out and wash the jar well.
- Start again from a dried backup, a spoonful of a friend’s starter, or flour and water.
What to expect: A new starter takes a week or two; dried flakes come back in about 3 to 7 days.
More on this:Mold or not?Make a new starter
Throw it out
Pink or orange streaks are unwanted bacteria
A pink, orange or red tint or streak is a sure sign of unwanted bacteria, King Arthur says: the starter has lost the acidity that kept intruders out.
Do this now
- Throw the starter out and wash the jar well.
- Start again from a dried backup, a spoonful of a friend’s starter, or flour and water.
What to expect: A new starter takes a week or two; dried flakes come back in about 3 to 7 days.
More on this:What to throw out, and what is harmlessMake a new starter
Hard to tell by eye
A thin white film: hard to call
A flat or wrinkled white film with no fuzz may be kahm yeast, a surface yeast, but you cannot be certain by eye.
Do this now
- When in doubt, throw it out and start again: a new starter takes a week or two, and a spoonful of a friend’s is faster.
More on this:Mold or not?
Easy to fix
A dry skin: peel it off and feed
A starter left unfed for a long time can form a dry skin, dark grey and wrinkled after months in the fridge. It looks awful, but it is not mold, and the starter underneath is usually fine (King Arthur).
Do this now
- Peel off the skin and scrape away dried bits on the glass.
- Take 50 g from the middle into a clean jar and feed it 50 g flour and 50 g water.
Look again in 12 hours.
What to expect: Throw it out instead if you find fuzz or pink or orange streaks under the skin.
More on this:Reviving a neglected starterMold or not?
Easy to fix
Nail polish or vinegar: it is hungry
Nail-polish, vinegar and strong alcohol smells mean the starter has run out of food. They fade within a feed or two and are no reason to throw it out.
Do this now
- Feed it now.
- For the next few days, feed a little more often or at a higher ratio such as 1:2:2.
Look again in 12 hours.
What to expect: A fed, healthy starter smells yeasty and mildly sour, a little fruity.
More on this:Smells that mean hungryFeeding ratios
Nothing is wrong
Normal in a new starter
In its first days a new starter often smells sharp or cheesy. That belongs to the early phase, before the yeast takes over, and it passes as the starter matures.
Do this now
- Keep to the daily feeds and keep the jar warm.
What to expect: Within a week or two it should smell pleasantly sour. Once it rises reliably, a smell that is not its usual clean, sour one means throw it out.
More on this:Making a starter, day by day
Throw it out
A foul smell means it has spoiled
King Arthur’s rule is to throw out a starter whose smell is not its usual clean, sour one. Sour, vinegar, alcohol and even nail polish are hungry smells; rotten, or simply wrong for your starter, is not.
Do this now
- Throw it out, wash the jar and start again.
What to expect: A new starter takes a week or two; a dried backup or a spoonful from a friend is faster.
More on this:When to throw a starter outMake a new starter
Nothing is wrong
That smell is a healthy starter
Yeasty, mildly sour and a little fruity is how a healthy starter should smell.
Do this now
- Carry on with your usual feeds.
What to expect: If it is not rising, the smell rules out spoilage: look at why it is slow.
More on this:It isn’t rising
Easy to fix
Too wet: weigh the feed
A starter fed by volume, or with more water than flour, ends up thin. King Arthur says that does no lasting harm: correct it with a little more flour, then weigh the next feeds.
Do this now
- Stir in a spoonful of flour now.
- Weigh every feed: equal weights of flour and water, or up to twice as much flour as water for a stiff starter.
What to expect: Whole grain flour soaks up more water, so a white-flour starter looks thinner than a rye one at the same weights.
More on this:Stiff vs liquid starterWeigh, don’t scoop
Easy to fix
A missed feed or two: just feed it
Missing a feed, or not feeding exactly 12 hours apart, will not come close to killing a starter (King Arthur).
Do this now
- Pour off any liquid, discard down to your usual amount and feed.
Look again in 12 hours.
What to expect: After one or two feeds it should rise as usual.
More on this:Reviving a neglected starter
Easy to fix
Weeks or months: a few days of warm feeds
A starter forgotten in the fridge is almost always alive, just very hungry. The longer it sat, the longer it takes: after a few weeks, 2 to 4 days of feeds; after months, up to a week.
Do this now
- Pour off the liquid and scrape away any dried or discoloured starter.
- Take 50 g from the middle into a clean jar and feed it 50 g unbleached flour and 50 g warm, not hot, water.
- Keep it at 75 to 78°F (24 to 26°C) and repeat every 12 hours.
Look again in 12 hours.
What to expect: Any rise or bubbles after the first two feeds means it is alive. It is back when it doubles within 4 to 8 hours.
More on this:Reviving a neglected starter
Easy to fix
Dried into a block: crumble, soak and feed
A little starter left for a very long time can dry into a hard, chalky block. King Arthur’s advice is to break it up, add water and feed it daily; if three or four days bring no growth and no bubbles, start over and stir some of the old starter into the new.
Do this now
- Crumble or grind it and soak it in twice its weight of lukewarm water until it dissolves.
- Stir in flour equal to its weight and keep it warm.
- Feed it every day.
Look again in 24 hours.
What to expect: Expect little for a day or two.
More on this:Reviving dried starterReviving a neglected starter
Start a new one
Heat has almost certainly killed it
Yeast dies at 140°F (60°C), and a starter suffers well below that, King Arthur says. A jar left in an oven that was then switched on is almost certainly dead.
Do this now
- Start again from a dried backup, a spoonful of a friend’s starter, or flour and water.
What to expect: Next time the jar sits in the oven to keep warm, tape a note to the oven door.
More on this:Make a new starterKeep a dried backup
Easy to fix
Frozen: it may well survive
A brief spell in the freezer is not likely to kill a fully developed starter: King Arthur thawed one after three days, and it rose well after a second feed. A long freeze does damage the yeast.
Do this now
- Thaw it at room temperature, then feed it as usual.
- Give it two or three feeds before you judge it.
Look again in 12 hours.
What to expect: Sluggish at first is normal. For a backup that keeps for months, dry a spoonful rather than freezing it.
More on this:Drying instead of freezing
Nothing is wrong
A metal spoon does no harm
Stirring with a metal spoon or keeping the starter in a stainless steel bowl will not kill it (King Arthur).
Do this now
- Carry on as usual; just do not keep it in copper or aluminum.
More on this:Choosing a jar
Nothing is wrong
Wrong amounts: no harm done
Too much or too little flour or water will not kill a starter. It may look too thick or too thin, and not rise the way you expect, for a feed or two (King Arthur).
Do this now
- Even out the consistency with a little more flour or water.
- Weigh the next feed; the feeding calculator gives the grams for any ratio.
More on this:Starter feeding calculatorFeeding ratios
Easy to fix
Dried flakes: soak, then feed for 3 to 7 days
Dried starter comes back reliably, but slowly at first.
Do this now
- Soak the flakes in twice their weight of lukewarm water, stirring now and then, until they dissolve, about 3 hours.
- Stir in flour equal to the flakes’ weight and keep it warm.
- Then feed 1:1:1 twice a day.
Look again in 12 hours.
What to expect: Little for a day or two, then rising. It is ready when it doubles within 4 to 8 hours.
More on this:Reviving dried starter
Nothing is wrong
A bought starter: follow the maker’s steps
The maker knows its own culture, so follow the steps that came with it. A dried one usually takes 3 to 7 days to wake; a fresh one is usually quicker.
Do this now
- Feed it the way the maker says, somewhere warm, with the level marked on the jar.
What to expect: It is ready to bake with when it doubles within about 6 to 8 hours of a feed.
More on this:The signs it is readyA starter someone gave you
Nothing is wrong
Not ready yet
Under double, with a flat top and few bubbles, it is still rising.
Do this now
- Give it more time, somewhere warm.
Look again in 2 hours.
What to expect: Look for doubled, domed and bubbly all through.
More on this:The signs it is ready
Ready to use
Ready: use it now
Doubled or more, domed and bubbly all through is the moment to mix it into dough or build your levain. Shortly after the peak is fine too; it will be a little more sour.
Do this now
- Weigh what your recipe needs, or build a levain with the feeding calculator.
- Feed what is left, so it is ready next time.
More on this:Work out the levainWhy the rise matters more than the float test
What you see and what it means
Find what your starter shows in the first column. Everything down to the white film can be put right; the last three rows mean start again.
| What you see | What it usually means | What to do |
|---|---|---|
| No rise a few hours after a feed | Too cool, too young, cold from the fridge, or it rose and fell while you were away | Find which, then keep it warm and feed twice a day |
| Streaks on the glass above the starter | It rose and fell: you missed the peak | Feed again and check sooner, or feed 1:2:2 to 1:5:5 so it peaks later |
| Bubbles, but the level hardly moves | Often too wet; a rye starter also rises less visibly | Weigh the feeds and add a little more flour for a feed or two |
| Quiet on days 3 to 5 of a new starter | The usual pause after the early rise from bacteria | Keep feeding once a day |
| Grey, brown or black liquid on top | Hooch: it is hungry | Pour it off or stir it in, then feed |
| A nail-polish, vinegar or strong alcohol smell | Hungry | Feed it, then feed more often or at a higher ratio |
| A sharp or cheesy smell in the first two weeks | Part of a new starter’s early phase | Keep feeding; it passes |
| Runny all through, even right after a feed | Too much water, or fed by volume | Stir in a little flour and weigh the next feeds |
| A dry, hard skin, dark after months in the fridge | Dried starter, not mold | Peel it off and feed from the middle |
| Sluggish after weeks or months unfed | Very hungry, almost always alive | Feed every 12 hours somewhere warm for 2 to 7 days |
| A thin white film with no fuzz | Possibly kahm yeast; you cannot be certain by eye | When in doubt, start again |
| Raised, fuzzy spots of any colour | Mold | Throw it out |
| Pink, orange or red streaks | Unwanted bacteria | Throw it out |
| A rotten smell, or one unlike its usual sour | Spoiled | Throw it out |
Is it dead? How to tell
A mature starter is hard to kill, King Arthur says. Missed feeds, feeds at odd times, the wrong amounts of flour or water, a metal spoon and a short spell in the freezer all leave it alive. Heat does kill it: yeast dies at 140°F (60°C), so a jar left in an oven that is then switched on will not survive. Long neglect can end in mold or pink streaks, and then it has to go.
The test is a feed. Take 50 g from the middle, feed it 50 g flour and 50 g warm water, and leave it 12 hours at 75 to 78°F (24 to 26°C). Any rise or bubbles mean it is alive: keep feeding until it doubles within 4 to 8 hours. No sign after a week of warm feeds (three or four days for a starter dried into a block) makes starting again the practical choice; stir a spoonful of the old one into the new.
Why a new starter goes wrong more often
In its first 6 to 10 days a starter is more open to mold and unwanted bacteria, because it has not yet built a mature starter’s defences, King Arthur says. Its early pattern also fools many bakers: a lively rise on day 2 from bacteria, a quiet spell on days 3 and 4, often a sharp or cheesy smell, then a steadier rise. Keep feeding through it, as in making a starter day by day.
Keeping trouble away
A clear, straight-sided jar makes every problem on this page easier to spot: which jar, and where to keep it.
- Feed on a routine: once or twice a day on the counter, about once a week in the fridge.
- Mark the level with a rubber band after every feed, so you can see the rise and the peak.
- Keep it at 75 to 78°F (24 to 26°C) when you want it lively, and in the fridge when you do not.
- Move it to a clean jar every week or two and wipe the rim after feeding.
- Dry a spoonful as a backup against mold or an accident (how to dry it).
Questions bakers ask
Can a sourdough starter go bad?
Yes, but rarely. Throw it out for fuzzy mold, pink or orange streaks, or a smell that is not its usual sour or alcohol smell. A well-kept mature starter is very hard to kill, King Arthur says.
How do I know if I killed my starter?
Feed it and give it 12 hours somewhere warm. Any rise or bubbles mean it is alive. Heat kills a starter, for example a jar left in an oven that was switched on; neglect, missed feeds and a metal spoon do not.
Is black liquid on my starter bad?
No. It is hooch, and it darkens from clear to grey, brown or black the longer the starter goes unfed. Pour it off or stir it in, then feed.
Can I bake with a starter that smells like nail polish?
Feed it first. The smell means it is hungry, and it fades within a feed or two. Bake once it doubles within about 6 to 8 hours of a feed.
My starter has bubbles but won’t rise. What is wrong?
It is alive. Often it is too wet: weigh the feeds and add a little more flour for a feed or two. A rye starter also rises less visibly than a white one.
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