Ingredients

You only need two ingredients to feed a sourdough starter. Be sure to see our tips on measuring the ingredients above. You can scale the ingredients up or down for your needs, but be sure to keep the ratio 1:1:1.

Sourdough Starter – Stir down your active starter if using a cup to measure
Water – filtered, non-chlorinated, room temperature or lukewarm water. Bottled spring water can work too. For cooler homes, give the starter a boost by using lukewarm water that is 85 degrees or less (optional). Cold water can slow the yeasts’ growth.
Flour – I use organic, unbleached all-purpose flour because it’s what most people have stocked and it’s affordable. You can swap 1/4 to half of the flour with whole wheat flour or rye flour to help the yeast strengthen. Regardless of what flour you use to feed a starter, you can use any type of flour to bake.

Pro Tip:

Many cities use chlorine to clean tap water, but the chlorine can hurt yeast growth. To dechlorinate tap water, boil and cool the water, or you can also leave a jug of water on the counter for a day while the chlorine evaporates.

How to Feed a Sourdough Starter

The process for feeding sourdough starter is so simple and takes only a few minutes. For refrigerated starters, feed once a week and start with step 1, but for room temperature starters, feed once a day and start at step 2 (or 3).

Bring to Room Temperature – put the cold starter on the counter for a few hours or overnight to come to room temperature.
Feed the Starter– Stir room temperature starter, then discard all but 100g (1/2 cup) of starter. Use a kitchen scale to measure 100g (1/2 cup) of water and 100g (1 scant cup) of flour. Stir into the starter until completely mixed.
Clean and Cover – use a silicone spatula to scrape down the sides of the jar and cover loosely with a lid or plastic wrap. Use a rubber band or dry-erase marker to mark the height of the starter and the date, so you can track its growth. Store the jar on the counter or fridge (if feeding for refrigeration, let it sit at room temperature for 1-2 hours to jump-start the process then refrigerate).

Pro Tip:

You do not need to change the jar for each feeding, but it’s good to clean every 1-4 weeks to help keep bad bacteria from contaminating the starter.

Do I have to discard sourdough starter every time I feed?

Technically no. Once it’s established, you can just feed it, but it will become very acidic over time since you aren’t discarding some of the waste/acid left over by fermentation, and the sheer volume would be hard to manage. You don’t have to waste the discard though.

Sourdough discard is just an unfed starter. To use it, try baking a sourdough discard recipe, sharing it with a friend (put it in a new jar, and feed it to make a second starter), frying it like a savory pancake, or refrigerating it in a separate jar until ready to bake.

Troubleshooting: Sourdough Starter Maintenance Tips

Maintaining a healthy starter sometimes depends on a variety of conditions: the humidity in your area, the temperature in your home, the type of flour used, the age of the starter, etc. Here are a few tips for getting the healthiest starter:

My sourdough starter is not doubling – continue to feed each day at the same time to help the starter gain strength. If the room temperature is below 70-75 degrees, consider moving the starter to a warmer spot. Try switching to bottled water if using tap water. Overall—patience is so important! Your yeast will grow if it’s in the right environment.
There’s a gray liquid on top of my starter -If you notice a dark liquid on the top (like in the picture below), don’t worry—that’s called hooch, the byproduct of fermentation. It means your starter is hungry. Pour it off or stir it in, discard half and feed.
My starter smells like rubbing alcohol – if there aren’t any colored streaks in the starter, this means it’s hungry. Discard and feed.
I forgot to feed/discard/stir my starter – don’t worry! Wild yeast is forgiving. Continue to discard and feed, and your starter should recover.
There are pink streaks in my starter – If you notice pink, green, or orange streaks, or green fuzz, bad bacteria has contaminated your starter. Throw it away, thoroughly wash your jar, and begin again.