New to sourdough and worried your starter isn't bubbling after a feed? You’re not alone and you’re not doing anything wrong. The truth is, visible bubbles aren’t the only sign of a healthy, active starter. In fact, there are plenty of other signs your starter is thriving, even if it looks calm on the surface.
What Healthy Fermentation Really Looks Like
When we think of a strong starter, big bubbles often come to mind. But fermentation is a biological process that begins microscopically before we see any visible change. Instead of focusing only on bubbles, here’s what else to look for:
Rise and Fall Between Feedings
Your starter should rise within 4-6 hours of feeding and then fall back as it consumes its food. If you notice streaks or residue on the sides of your jar, that’s a great sign it’s active.
Tangy, Slightly Sweet Smell
A healthy starter smells pleasantly sour, think tangy yoghurt or vinegar. If it smells sharp or funky (like nail polish or rotten cheese), it may need more regular feeding.
Bubbles Inside (Not Always on Top)
Some starters, especially thicker ones, trap bubbles inside the doughy mass rather than on the surface. Give your starter a stir with a spoon and check for bubbles within.
Beginner Tip: Try using a clear jar with a rubber band or marker to track your starter’s rise. It’s the easiest way to see growth without relying on surface bubbles.
Why You Might Not See Bubbles
It can be frustrating when your starter looks flat, especially when you're following every step to the letter. Here are a few reasons why visible bubbles might be missing:
Cooler Temperatures = Slower Fermentation
Starters love warmth. If your kitchen is under 22°C, fermentation slows dramatically. This can delay visual signs like bubbles or rising.
Thicker Starters Trap Gas
If your starter has a low hydration ratio (meaning it’s thicker), gas builds up inside rather than appearing as surface bubbles. That doesn’t mean it’s not active!
Activity Starts Microscopically
During the early days of a new starter, much of the fermentation happens below the surface and isn’t immediately visible. Be patient and consistent, things are happening!
Beginner Tip: Avoid switching containers or stirring too often, which can disturb the gas buildup and mask visual signs of fermentation.
How to Boost a Sluggish Starter
If your starter seems to be taking longer than expected, here are some ways to gently nudge it along:
Keep the Temperature Warm (but not hot)
Aim for a consistent room temperature between 25-28°C. You can:
- Place the jar in your oven with the light on (but oven off!)
- Set it near a warm appliance
- Use a proofing box or electric fermenting heat box
Switch Up Your Flour
Wholemeal or rye flours are rich in nutrients and wild yeast. Adding 1-2 tablespoons to a feed can give your starter a boost.
Use High-Protein Flour
Always use flour with 12% protein or more. This helps with gluten development and feeds the starter more effectively.
Check Your Consistency
Your starter should be the consistency of thick pancake batter. If it’s too thick, it won’t show activity; too runny, and bubbles may collapse before you see them.
Stick With It
Even without visible change, keep feeding every 24 hours. Consistency is key, especially in the first week.
Beginner Tip: Filtered or dechlorinated water is best. Tap water can contain chemicals that inhibit fermentation.
Final Encouragement: Trust the Process
Sourdough isn’t meant to be rushed. Every environment, every flour, and every jar of starter is a little different. Some take 3 days to show life; others take a week or more. As long as it smells good, shows rise, or has internal bubbles, you’re doing great.
Still not sure? We’re here to help! Reach out via our contact page or explore more of our starter care tips.