Flavour & Fire
The Sourdough Journal
Feeding Your Starter
At some point, you stop watching the clock and start watching your starter instead. That is what this article is about: learning to recognise what your jar is telling you.
A starter is constantly giving you signals. Bubbles, volume, texture and aroma all change as fermentation progresses, and together they tell you far more than a single point on the clock ever could.
Four things to look for
Bubbles. Small bubbles throughout the mixture, with larger ones around the sides or across the surface, show that gas is being produced during fermentation. The number and size of the bubbles can vary considerably depending on the flour, hydration and starter itself. Bubbles are therefore most useful when considered alongside everything else your starter is doing.
Volume. An active starter will visibly rise after feeding. A simple elastic band around the jar is surprisingly useful here: mark the level immediately after feeding and you can easily track how far it rises. More important than how high your starter gets, however, is the pattern. A starter that reliably rises after feeding and then falls again is showing a recognisable fermentation cycle.
Texture. As fermentation progresses, a starter can become lighter and more aerated. You may see a network of small holes when you stir it or move the jar. After the peak, it usually becomes denser again as the volume begins to fall. Different flours and hydration levels create different textures, so the most useful thing is to learn what your own starter looks like.
Aroma. A healthy starter smells sour and lively. It might be mild and yoghurt-like, fruity, lightly alcoholic or distinctly sharper, depending on factors such as temperature, flour and feeding routine. A distinctly unpleasant, rotten smell is different and is a reason not to use the starter.
Recognising the peak
After feeding, your starter goes through a cycle. At first, little seems to happen. Then the first bubbles appear, the volume begins to increase and the activity becomes more obvious. Eventually, the starter reaches its highest point: the peak.
It does not stay there indefinitely. The volume gradually begins to fall and the texture changes again as the available nutrients are consumed during fermentation.
For many types of baking, the peak is a useful time to use your starter because fermentation activity is high. But there is no universal moment when every starter reaches its peak. Temperature, flour, feeding ratio and the amount of active starter you begin with all influence the pace.
The height of the peak varies too. One starter may more than double, while another may rise much less. The height alone is therefore not a reliable measure of how healthy a starter is. The recurring pattern is more revealing: does your starter reliably become active after feeding, rise clearly, reach a recognisable high point and then fall again?
That pattern tells you a great deal.
When is a starter ready to bake with?
Not every bubble means your starter is ready to bake with. A useful, well-established starter should show reliable fermentation activity after feeding.
Look for a combination of signs:
- it becomes clearly active after feeding
- bubbles appear throughout the mixture
- the volume visibly increases
- it reaches a recognisable peak
- this pattern repeats over several feedings
- the aroma is pleasantly sour and lively
A young starter can produce plenty of bubbles without yet being strong enough to reliably raise a loaf. Especially during the first few days, activity can appear surprisingly vigorous and then fade again. Rather than judging your starter by one impressive feeding, look at what it does consistently.
In the end, the best indication is not a trick, but repeatability.
And what about the float test?
You have probably come across the familiar float test: dropping a spoonful of starter into water to see whether it floats.
It sounds useful, but it is not a reliable general test for starter maturity. Whether a piece of starter floats depends partly on how much gas it contains, but also on its structure and hydration. A starter can be active and perfectly capable of raising dough without floating.
It is better to rely on what you can observe in the jar itself: rising, bubbling, peaking and the recurring pattern between them.
How often should you feed it?
How often you feed your starter depends mainly on where it lives and how active it is there.
At room temperature, an established starter that is used regularly will often need feeding every day. In a warm kitchen, a lower ratio such as 1:1:1 can move through its food more quickly and may require an additional feeding. In a cooler environment, the same starter can take considerably longer to complete its cycle.
In the fridge, fermentation slows considerably. An established starter can generally sit there for about a week without feeding, sometimes longer. When you want to use it again, give it one or more room-temperature feedings to bring it back to full activity. For that process, see Storing Your Starter.
The clock is a guideline
A starter can change considerably from one day to the next, particularly when the temperature or flour changes. That is why timing is useful as a guide, but not as the final measure.
A warm kitchen speeds things up; a cooler one slows them down. A different flour can change the texture. A different feeding ratio can shift the point at which your starter reaches its peak.
The more familiar you become with your starter, the less you need to rely on the clock. You begin to recognise where it is in its cycle simply by looking at it.
Signs that need attention
Not everything that looks unusual is immediately a problem. A starter can change quite noticeably from day to day, especially when temperature or flour changes. Still, there are a few signs worth paying attention to.
Little or no activity after several feedings can have several causes. The environment may be too cold, the starter may not be receiving enough food, or it may still be in an early stage of development.
A layer of liquid on top — often called hooch — is usually a sign that the starter has used up much of its available food. On its own, it is not a reason to panic. The colour and aroma of the starter still matter, however.
Progressively weaker activity may indicate that the starter has become unbalanced or that its conditions have changed. Before changing several things at once, look at temperature, feeding routine, ratio and flour.
For these and other irregularities, and what to do about them, continue to Starter Problems. For signs that mean a starter should be discarded — such as visible mould or striking pink or orange discolouration — see Starter Health & Safety.
Learning to watch rather than measure
The best way to get the feel for this is simple: feed your starter, mark the level and take a look every so often.
Notice when the first bubbles appear. Watch when the rise begins to accelerate, when your starter reaches its highest point and what it looks like afterwards. Smell it before and after the peak. Do this for a few feeding cycles and you will begin to recognise the rhythm of your own starter.
That rhythm will not be exactly the same every day. A warm kitchen speeds things up; a cooler one slows them down. Different flour can change the structure. A different feeding ratio can make your starter peak earlier or later.
That is precisely why learning to watch is ultimately more valuable than memorising a schedule.
Your starter does not need to be ready at a particular time. What matters is learning to recognise where it is in its cycle, and what that means for what you want to do with it.
Bubbles are its way of talking. You just have to learn the language.