Runny sourdough starter? You’re not alone. This is one of the most common questions we get from bakers starting out and the good news is, it’s almost always a simple fix.
A watery starter isn’t a sign that something is ruined. In fact, it often means just one thing: your starter is hungry. Let’s break down why it happens, how to thicken it up, and what consistency you should be aiming for.
Why Is My Starter Too Runny?
There are a few different reasons your starter might look more like soup than thick porridge. But don’t stress, they’re all easy to address:
Too Much Water in the Mix
If you’re not weighing your ingredients by grams, it’s easy to accidentally add too much water. Sourdough is precise. Volume (like cups and tablespoons) can vary a lot depending on your flour. Always weigh ingredients for consistent results.
White Flour Absorbs Less
If you’re feeding your starter with white flour only, you’ll notice a looser texture. That’s totally normal, white flour doesn’t absorb as much water as whole wheat or rye, so it can look runnier even if you’re feeding it correctly.
Warm Room = Faster Fermentation
In a warmer kitchen (above 26°C), your starter ferments faster. This breaks down the flour more quickly and leaves the mixture thinner. This is especially common in summer or if your starter lives near a warm appliance.
It’s Just Hungry
The most common reason of all? It’s simply time to feed it. A runny starter is often just one that’s digested its food and needs a fresh meal. Think of it as your starter saying, “I’m ready for a top-up!”
Beginner Tip: If your starter is getting runny within 12-16 hours of feeding, you might need to either feed more often or reduce how much starter you're keeping.
How to Fix It
Luckily, this one is easy to solve with a few smart tweaks:
Adjust Your Feeding Ratio
Try a 1:1:1 feeding (equal parts starter, flour, and water by weight) or go thicker with 1:2:1 (more flour, less water).
For example:
- 25g starter
- 50g flour
- 25g water
This thickens your mix and helps it hold structure.
Use Whole Wheat or Rye Flour
Whole wheat and rye flours are more absorbent and naturally help thicken your starter. They also boost microbial activity, which can bring a sluggish starter back to life.
Feed More Often in Warm Weather
If your kitchen is warm, fermentation happens faster so feed your starter more frequently to stay ahead of the breakdown. If you're feeding once every 24 hours, try every 12-16 hours instead.
Refresh It With a Discard and Feed
Don’t skip the discard step. Throwing away most of your starter and feeding it fresh flour and water resets the balance and gives the yeast and bacteria a clean slate to thrive.
Beginner Tip: Freshly fed starter should feel like thick porridge. Use that texture as your guide.
What Should It Look Like?
As your starter matures after feeding, it’s supposed to change consistency that’s a good sign! Here’s what to expect:
Just Fed
Feels like thick porridge or soft dough. This gives it strength and allows it to trap gas as it ferments.
A Few Hours Later
Starts to look more like mousse, airy and bouncy.
Fully Mature
Thinner and looser, similar to pancake batter. That’s normal! It means the flour has been broken down and fermented.
Beginner Tip: If you’re not sure whether your starter is still strong, mark the jar with a rubber band when you feed it. If it rises significantly (doubles or more), it’s doing great, even if it looks runny!
When to Worry
Runny starter isn’t usually a bad sign, but there are a couple of exceptions to keep in mind:
Bad Smells
If your starter smells like nail polish remover, rotten eggs, or meat, it might be over-fermented or contaminated. Give it a few discard-and-feed cycles and see if it improves.
No Activity
If your starter is thin and not rising or bubbling at all, it may be struggling. Try a refresh feed with a 1:2:1 or 1:2:2 ratio, add a little rye or wholemeal, and place it somewhere warm (25-28°C).
Final Thoughts
A runny sourdough starter is usually a simple fix. Most of the time, it just needs a feed or a small tweak to your flour, temperature, or hydration.
Stick with daily feeding, weigh your ingredients, and don’t forget that natural fermentation is a process. Give it time, adjust the conditions, and you’ll be back to a thick, happy, bubbly starter in no time.
And remember: if you ever feel stuck, we’re here to help you nail your bake.