Guide to Sourdough Starter

Creating a sourdough starter might seem intimidating at first, but it’s actually a straightforward and forgiving process. This natural leavening agent, made from just flour and water, harnesses wild yeast and bacteria from the environment to develop the perfect foundation for baking delicious, tangy sourdough bread. With a bit of patience and consistency, anyone can cultivate a robust starter that will reward you with flavorful and airy loaves time and time again.

Before you Begin:

  • Mix equal parts by weight AP flour and whole wheat flour (e.g., 500 g each) and store in an airtight container. This 50/50 flour mixture will be used to create your starter and to feed it each time.
  • You will need to use a jar that is at least twice the size of the volume of your starter to allow for it to rise and fall.
  • If you have been gifted an active sourdough starter, awesome! You can skip the next section and look for how to feed and store your new starter.

To Make the Starter from Scratch:

  • Add 100 g of your 50/50 flour and 100 g of luke warm water to your container and mix until it forms a thick batter with no lumps.
  • Cover the container with a kitchen towel and place in a cool, shaded sport for 2-3 days.
  • After 2-3 days, check to see if there are any bubbles forming around the sides or on the surface; if not, let it sit for another day or two. If a crust starts to form, just peel it back and discard.
  • Once you note some bubbles and the mixture starts to smell stinky (like ripe cheese) and/or tastes acidic – it’s time to start feeding!

To Feed and Store the Starter:

  • First, discard approximately half of the contents in the container.
  • Next add equal parts of water and your 50/50 flour mixture by weight.
  • Mix thoroughly to combine.
  • Cover loosely with a lid or kitchen towel.

The amount of flour mixture you add will depend on if you are planning to bake soon, and how much. If this is a brand new starter, you will want to feed it for at least 10 days to ensure it is rising and falling predictably and the balance of yeast and bacteria has been established. For this, adding ~40-50 g each of water and four is sufficient. Don’t worry too much about the exact amount you add each time; just ensure you maintain the consistent 1:1 ratio of the flour mixture to water. Keep the starter at room temp throughout this period. 

If the starter is mature and you are just maintaining it, adding 40-50 g each of water and four is sufficient if you aren’t baking soon. If you are baking bread the same/next day, you will want to add more – I feed my started 80-100 g each of water and flour mixture the day I plan to make 2 loaves of bread. 

The feeding schedule for a mature starter will depend on whether you are leaving the starter at room temperature or storing it in the in the fridge.

  • Room temp: feed the starter every day.
  • Fridge: feed your starter once to twice a week.

If you aren’t going to bake for a while, I suggest leaving it in the fridge or else you will go through a lot of flour. If you don’t feed it every week while it is in the fridge, don’t worry, it will be fine you just may see a dark liquid (called hooch) on the top forming overtime. If this happens just discard the liquid and feed the starter as you normally would to revive it.

If you are leaving it at room temperature, make every effort to feed it every day at roughly the same time. If you forget to feed it one day, don’t worry it should be fine, just feed it the next day. Try to avoid neglecting it for a long period of time, as it could start to go moldy.

Equipment Needed:

  • Kitchen scale
  • Container (plastic or glass is fine)
  • Spatula 


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Overnight Sourdough Bread Recipe 

NOTE: Certain links found within this article may lead to affiliate pages Beth Koster has been making sourdough bread for our family for close to 10 years. These are the instructions she sends to friends and people who get starter from her when they start their own sourdough journey. Beth will be posting an instructional […]

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