When is a sourdough starter ready?

The readiness of a sourdough starter, for baking or otherwise, depends greatly on the age (hours since refreshment) of the starter in it’s perpetual cycle of refreshment. Here’s a little diagram of this cycle which we will explore in the text below:-


How old is your sourdough starter?

Your starter cycle begins at hour zero (the point at which you refresh it), at which point you have a small seed amount of mature culture, and a whole heap of food. Your starter will then go through three stages over a 24 hour period:-

  • Young – 0-8 hours
  • Vibrant – 8-16 hours
  • Mature – 16-24 hours

[Note these times will vary with temperature of the starter and it’s hydration, but are a good starting point when thinking about when a sourdough starter is ready]

How can you tell what stage a starter is at?

You need to a) know the stages it will go through, and then b) use your senses! Here’s how:-

  • Taste it – eww I hear you say, but taste is a great way to ascertain starter age. Grab a spoon and get tasting:-
    • Young – the starter will taste floury, a bit “flat” and generally tasteless
    • Vibrant – the starter will taste milky sweet and/or slightly sour, depending on what side of the vibrancy peak you catch it on – this is the taste to remember and to aim for when baking!
    • Mature – the starter will taste progressively more and more sour, fermented and vinegary.
  • Look at it – in two ways a) number and size of bubbles and b) the overall volume
    • Young – visible bubble formation after a lag following refreshment. Bubbles  start small in number and size, but increase steadily towards the vibrant stage. Volume will begin to swell towards the end of youth.
    • Vibrant – Notable bubbles, large and small in ever increasing number. Increase in volume, with foam bubbling on the surface of fermenting goodness.
    • Mature – Volume decreases, as large bubbles from vibrant stage are expelled, and as micro-organisms generally slows down as food is consumed. Small bubbles, fairly evenly distributed through the starter will remain entrained unless disturbed.
  • Smell it – get your nose in and have a smell:-
    • Young – starter smells floury and inactive
    • Vibrant – Smells of wholesome fermenting grain, with slight wafts of vinegar – remember this smell!
    • Mature – starter smells more and more vinegary,
  • Float it – take a spoon full of starter and drop into a container of water. It will either sink or float, based directly on its bubble development and buoyancy.
    • Young – will sink like a stone!
    • Vibrant – will happily float away on the surface of the water
    • Mature – will sink slowly

What stage to use it?

What stage to use your starter depends on what you are doing with it:-

  • Ready to store – use it when Young – early on in the starters cycle (i.e. immediately after feeding) is the optimum time to store the starter culture. At this stage immediately after feeding, there is a small seed amount of mature starter, and a whole heap of un-fermented food for eating. This is a good point to put to store in a cold place like the fridge.
  • Ready to bake – use it when Vibrant – midway through the starter cycle you will reach the optimum time to bake (i.e. turn your starter into a production sourdough). Depending on exactly when you use it, and the amount you use, will ultimately impact on the taste of your loaf. Earlier in the cycle, when the starter is young = less sour, later in the cycle, when the starter is mature = sour!
  • Ready to refresh, dry or freeze – use it when Mature – later on in the starter cycle, you will have a mature starter which can either be refreshed as normal, or you can take your mature, strong population of sourdough micro-organisms and store them by drying (check out this post) or freezing.

16 thoughts on “When is a sourdough starter ready?”

    1. Thanks Eric – I think the guide in writing on Sourdough starters should include more graphics like these – pictures help explain 🙂

  1. The float test depends on the hydration of the starter. Thicker starters can be fully ready and never, ever float. SO much depends on the starter that it is hard to give iron clad rules, or even rules of thumb. If I used the float test, I’d mention the hydration of the starter.

    1. Very good point Mike, I hadn’t Though to caveat these rules of thumb! I think a post on Starter Hydration might be next on the blog 🙂

  2. My Friend, After kneading to get a beautiful bubble airy crumb, the batch to be in “vibrant” area, do I have to wait to rise between 8-16h? Stefan

    1. Hi Gulyas – this post was all about sourdough starters more than production sourdough (I think I need to write a blog post on all the sometimes confusing terms bakers use to describe the same thing!) – once you’ve used your starter to make a dough, time to prove for a crumb depends on temp, amount of starter and hydration. It often is a period between 8-16hr or even longer, but often has folds, pre-shaping and shaping thrown in – recommend you check out any basic sourdough loaf recipe 🙂

  3. Very helpful. A follow on question: If a recipe calls for you to make a production levain/starter (ie an intermediate stage between starter and mixing the final dough), do the same timings/characteristics you’ve outlined above apply? I’ve noticed that often they only call for this to be left at room temp for a much shorter period, say 3-4hrs. Is this because it needs to be used at a much younger stage, or does it just develop more quickly? Thanks for a great blog – any advice appreciated!

  4. Depending of the circumstances proofing the dough maybe 8-16H after this chart. But myself I marked in the proofing basket the start height and when I see it is now doubled, let bake it! With yeast over 1H and with SD around 3-4H, from the time when I added the SD!

  5. Hello! I’m very new to sourdough starter and this post is very useful to me. My sourdough starter is just 5days-old and I’ve been googling about “active starter”. Many thanks to your helpful information!

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