In this helpful guide, I share everything you need to know about buying, feeding, maintaining, and storing a healthy sourdough starter. Below you will find video guidance and step-by-step instructions. Let’s do it!

Purchased sourdough starters from King Arthur Flour and Breadtopia.

If you are interested in dipping your toe into sourdough bread baking, for starters you’ll need a starter (hah!). In this sourdough starter guide I share my top tips for:

Though I offer instructions on how to build a sourdough starter from scratch below, I am a huge proponent of purchasing a starter. I outline why in more detail here — Sourdough Focaccia: A Beginner’s Guide — but in short, it’s because:

  • If you’re curious about sourdough, get to it! Making a starter from scratch can take weeks.
  • They’re relatively cheap (or free if you get one from a friend or baker).
  • A purchased starter potentially will be stronger/more active than a young, homemade starter.

Where to Purchase a Sourdough Starter

I have had success purchasing and activating sourdough starters from three places:

Each place offers guidance for “activating” the starter. Breadtopia’s instructions live on its website. King Arthur Flour sends along a booklet with details, but also provides online help. Cultures For Health offers video guidance here.

In short, to “activate” each, you simply add flour and water, stir, and wait — that’s all there is to feeding a sourdough starter.

How to Activate a Sourdough Starter

A purchased starter generally arrives in a small bag or container. I’ve created a short video for activating a King Arthur Flour sourdough starter. You can use this same process for activating a Breadtopia starter as well:

Follow these steps to activate it:

  1. Place starter in a vessel. I love these deli quart containers for this purpose.
  2. Add 45 g each of all-purpose flour and room-temperature water. (Note: You may need to add a little more flour or water to get the consistency right, which should be like a thick batter.)
  3. Wait. You may see bubbles and action (rising!) in as few as 6 hours; it may take more like 18 to 24 hours. Variables include the time of year, the temperature of your kitchen, the temperature of your water, how much water and flour you used, etc.
  4. When the starter has roughly doubled in volume, it’s likely ready to go. Drop a spoonful of it in a glass of water. If it floats, you’re ready!
  5. If it doesn’t float after 24 hours, add more flour and water (equal parts), stir again, and wait.
  6. If you aren’t seeing any action after another 12 hours, discard most of it, and add more flour and water (equal parts), stir, and wait. Just be patient. Before you know it, your starter will be rising and bubbling and ready to go.

How to Feed A Sourdough Starter

If your starter floats, and you’re ready to start baking, measure the required amount into a bowl and proceed with the recipe. Here are three great beginner’s sourdough recipes:

  1. Simple Sourdough Focaccia: A Beginner’s Guide
  2. Simple Sourdough Bread: A Step-by-Step Guide
  3. Favorite, Easy Sourdough Bread (Whole Wheat-ish)

If you’re not ready to bake, discard most of it, add an equal amount of flour and water (45 g each or so), stir it together, cover it, and stash in your fridge.

My preferred storage vessel is a deli quart container. When I store my starter in the fridge, I use the lid that comes with the quart container. When I feed my starter and let it sit at room temperature, I use a breathable lid.

From here on out, you’ll need to feed it roughly once every two weeks — I’ve left it for as long as three-four weeks without a feeding, and it has been fine, but I don’t recommend waiting that long in between feedings.

Here’s the play-by-play:

1. Place the vessel holding your starter on a scale, and add 45 g flour:

feeding the sourdough starter with flour

2. Add 45 g water:

A quart container on a scale holding a sourdough starter, water, and flour

3. Stir together and mark the top of the mixture with a rubber band:

A quart container holding a just fed sourdough starter.

4. Wait until the starter doubles or nearly doubles:

A quart container holding doubled in volume sourdough starter.

5. Test it! If it floats, you’re good to go!

A cup of water holding a spoonful of sourdough starter floating.

Before long, you’ll get the hang of your starter’s rhythm: how it rises and falls, how it behaves when you feed it more regularly, how it behaves when you neglect it, how it smells at various stages, etc.

When you’re ready to bake, the goal is to “catch” the starter at its peak — this is when it is the strongest/most alive. If you miss the opportunity, and the starter collapses, don’t despair: simply discard some of it (or don’t), and feed it again with equal parts flour and water by weight, stir, and set it aside to rise again.

Maintaining a Sourdough Starter

  • Something that deterred me from sourdough for a long time is the waste element: I hated discarding so much and “feeding” so much. I’ve learned over time that there are ways to keep your starter on the lean side to reduce the waste factor. Here’s how:
  • After I use my starter for a bread recipe, I do one of two things:
    1. If there is a fair amount of starter left (a half cup or 100 g), I simply stir it up, cover it, and stash it in the fridge.
    2. If there are only a few tablespoons of starter left, I like to replenish it with a very small amount of flour and water (45 g of each).  Once I add the flour and water and stir it all together, I cover the vessel, and stash it in the fridge.
  • Every time I use it or feed it, I discard most of it, and feed it with equal amounts by weight water and flour.
  • When life gets in the way, and I can’t find time for sourdough, I tend to it every 2-3 weeks by discarding most of it, and feeding it with 45 g each flour and water.

Storing a Sourdough Starter

As noted above, my preferred storage vessel is a deli quart container. When I store my starter in the fridge, I use the lid that comes with the quart container. When I feed my starter and let it sit at room temperature, I use a breathable lid.

Ideally, strive to feed your starter roughly once a week or every two weeks if you are not finding time to bake regularly. If you are baking regularly, feeding your starter once a week will be a natural part of your baking rhythm. If you are looking for ideas for what to do with the discard, try these sourdough flour tortillas or make peasant bread as outlined in this troubleshooting post.

As noted above, I’ve left my starter for as long as three to four weeks without feeding it, and it has “awakened” beautifully, though I don’t recommend, if you can help it, waiting that long in between feedings.

How to Tell if Your Starter is Healthy

If you are just getting started with sourdough, it may be hard to “read” the various smells of your starter. Depending on what “phase” a starter is in — i.e. freshly fed or neglected for weeks in the fridge — it can smell anywhere from stinky and acidic to fresh and sweet.

Don’t be alarmed if your starter, upon pulling it from the fridge, smells a little funky. It might smell like alcohol or, as one commenter noted: dirty socks. As soon as you discard most of this sharp-smelling starter and feed it with equal parts flour and water, the aroma will instantly change. As your starter rises and approaches a doubling point, it should smell fresh and sweet.

You know you have a healthy starter when it …

  1. … doubles in volume within 4 to 6 hours (roughly) of feeding it.
  2. … floats when you drop a spoonful of it in water.

So how do you know if your starter is bad? When …

  1. … you see mold.
  2. … it doesn’t rise or is slow to rise after a feeding.

Unfortunately, if you see mold in your starter, you probably should toss it, and start over. Alternatively, you could scrape off the moldy bits, transfer a few tablespoons of what looks healthy (not moldy) to a clean jar, and feed it with equal parts flour and water.

If your starter is not doubling in volume within 4 to 6 hours of a feeding you should spend a few days strengthening it. This is what I always recommend:

  • Be aggressive with how much of it you are discarding: throw away most of it, leaving behind just 2 tablespoons or so. Feed it with equal parts by weight flour and water. Start with 40 g of each or so.
  • Use water that you’ve left out overnight to ensure any chlorine has evaporated. (This isn’t always necessary, but it might make a difference.)
  • Buy distilled water. In some places, letting water sit out overnight will not be effective, and your tap water may kill your starter.
  • Feed your starter with organic flour or a small amount of rye flour or stone milled flour (fresh or locally milled if possible). My store sells 2-lb. bags of King Arthur Flour organic all-purpose flour for $3.49 — I use it exclusively for feeing my starter.
  • Once you feed your starter, cover the vessel with a breathable lid, and leave it alone at room temperature. After 6 hours (more or less), repeat the process: discard most of it and feed it with 40 g each flour and water.

Once you have a strong starter on hand — one that is doubling in volume within 4 to 6 hours — you can bake with it (using it at its peak doubling point) or stash it in the fridge. When you feed your starter, place a rubber band around the vessel to mark the starter’s height, which helps gauge when it has doubled

Questions? Thoughts? Shoot!