I’ve been baking sourdough for a few months now, and most days the starter smells tangy and yeasty, which feels right. But a couple of mornings this week, I opened the jar and was hit with a strong smell like nail polish remover or acetone. I’ve read that it could mean the starter is stressed or starving, but I fed it the same way as usual - equal parts flour and water, kept it at room temp around 70°F. I even tried switching to a different flour brand to see if that helped, but the smell came back. The starter still bubbles and rises, just with this weird smell. Should I be worried it’s going bad and toss it? Or can I revive it somehow? What’s the best way to fix a starter smelling like this without losing all the work I’ve put into it?

On 01/23/2026 at 10:35 PM, SunnyLife101 said:

I’ve been baking sourdough for a few months now, and most days the starter smells tangy and yeasty, which feels right. But a couple of mornings this week, I opened the jar and was hit with a strong smell like nail polish remover or acetone. I’ve read that it could mean the starter is stressed or starving, but I fed it the same way as usual - equal parts flour and water, kept it at room temp around 70°F. I even tried switching to a different flour brand to see if that helped, but the smell came back. The starter still bubbles and rises, just with this weird smell. Should I be worried it’s going bad and toss it? Or can I revive it somehow? What’s the best way to fix a starter smelling like this without losing all the work I’ve put into it?

That acetone smell is definitely a sign your starter is running low on food and producing those funky byproducts. Even if you’re feeding it the same way, sometimes the balance of yeast and bacteria shifts, especially if the temperature or humidity changes a bit. I’d try discarding most of the starter and feeding it fresh flour and water more frequently - maybe twice a day for a couple of days - to help it bounce back.

Also, some folks find switching to whole grain flours like rye or whole wheat can give the starter a nice boost since they have more nutrients. Just keep an eye on the smell and bubbles; if it’s still rising well and smells more pleasant after a day or two, you’re probably in the clear. No need to toss all your hard work yet!

That acetone smell is definitely a sign your starter’s hungry and producing excess acetic acid. It’s great that it’s still bubbly and rising though - that means it’s alive and can bounce back. Sometimes starters get a bit out of balance if you don’t feed them often enough or if the environment changes slightly, even if you think you’re feeding the same way.

Try giving it a couple of regular feedings with a bit more flour relative to water (maybe a thicker consistency) and keep it at a stable room temp. Some folks find switching to whole grain flour for a feeding or two helps boost the yeast activity and cut down that sharp smell. If it still smells off after a few feedings, you might want to discard a portion and refresh with fresh flour and water to reset it. But don’t toss the whole thing just yet - you’ve got a resilient starter on your hands!

That acetone smell is definitely a sign your starter is a bit out of balance, but it doesn’t mean you have to toss it just yet. It usually happens when the yeast is running low on food and the bacteria start producing more acetic acid, which gives that nail polish remover vibe. Since you’re feeding regularly and keeping it around 70°F, maybe try increasing the feeding frequency or giving it a bit more flour and water at each feed to help it bounce back faster.

Also, some folks find switching to a mix of whole grain and white flour can help stabilize the starter’s microbial community. I’ve had a similar smell pop up when I accidentally let my starter go too long between feedings, but a few consistent feedings with a bit more flour fixed it right up. Just keep an eye on the bubbles and rise - if those are still strong, you’re on the right track!

On 01/23/2026 at 10:35 PM, SunnyLife101 said:

I’ve been baking sourdough for a few months now, and most days the starter smells tangy and yeasty, which feels right. But a couple of mornings this week, I opened the jar and was hit with a strong smell like nail polish remover or acetone. I’ve read that it could mean the starter is stressed or starving, but I fed it the same way as usual - equal parts flour and water, kept it at room temp around 70°F. I even tried switching to a different flour brand to see if that helped, but the smell came back. The starter still bubbles and rises, just with this weird smell. Should I be worried it’s going bad and toss it? Or can I revive it somehow? What’s the best way to fix a starter smelling like this without losing all the work I’ve put into it?

That acetone smell is pretty common when your starter’s running low on food and producing excess acetic acid. Even if you’re feeding it the same way, sometimes the balance of yeast and bacteria shifts, especially with temperature changes or flour variations. Since you mentioned it still bubbles and rises, it’s likely just a phase rather than a lost cause.

Try feeding it a bit more frequently or increasing the feeding ratio (like 1:2:2 starter:flour:water) for a few days to give it a boost. Also, stirring it once or twice between feedings can help redistribute the microbes. If the smell persists or the starter stops rising, then you might want to start fresh, but usually a little extra TLC brings it back.

On 01/23/2026 at 10:35 PM, SunnyLife101 said:

I’ve been baking sourdough for a few months now, and most days the starter smells tangy and yeasty, which feels right. But a couple of mornings this week, I opened the jar and was hit with a strong smell like nail polish remover or acetone. I’ve read that it could mean the starter is stressed or starving, but I fed it the same way as usual - equal parts flour and water, kept it at room temp around 70°F. I even tried switching to a different flour brand to see if that helped, but the smell came back. The starter still bubbles and rises, just with this weird smell. Should I be worried it’s going bad and toss it? Or can I revive it somehow? What’s the best way to fix a starter smelling like this without losing all the work I’ve put into it?

That acetone-like smell is definitely a sign your starter is a bit out of balance, even if it’s still bubbling and rising. It usually means the yeast is running low on food and producing those solvent-like compounds. Since you’re feeding equal parts flour and water, maybe try increasing the feeding frequency or the amount of flour for a few days to give it a boost. Sometimes a warmer spot or a different flour blend (like adding some whole wheat or rye) can help too.

I’ve had my starter do this after a few days of neglect or if the room gets cooler than usual. It usually recovers fine with a couple of good feedings. If it starts to turn pink or develop mold, then it’s time to toss, but that smell alone isn’t a death sentence. Just treat it like a hungry pet for a bit!