How to Feed Sourdough Starter: Ultimate Guide

Feeding a sourdough starter is one of the most important parts of making great sourdough bread. It keeps the starter healthy, strong, active, and ready for baking.

Now, stick with me, and I will teach you how to take good care of your starter. In this guide, I will show you how to feed your starter to make sure it has the optimal balance of wild yeast and lactic acid bacteria.

Once your starter is active and established, whether you made it yourself or rehydrated a dried one, you will begin a regular feeding routine. Don't forget to print my sourdough starter feeding log to keep track of its progress.

And if you don't have a starter yet, start with my Beginner Sourdough Starter Recipe.

What is an active sourdough starter?

An active sourdough starter is an established colony of wild yeast and lactic acid bacteria. These microorganisms are responsible for making sourdough bread rise and give it a tangy, unique flavor.

The wild yeast in the starter eats the natural sugars in the flour and produces carbon dioxide, which drives the fermentation process.

If you are starting from scratch, it may take approximately 3 to 4 months for the starter to mature. While you can begin baking earlier, the quality of your bread might vary. A healthy sourdough starter should double or even triple in volume before the next feeding.

Feeding sourdough starter: what it means

Feeding a sourdough starter is often described as removing a portion of the starter before "giving it food" (flour and water), a process known as discarding. However, biologically, each feeding resets the entire fermentation system.

When you feed your sourdough starter, you add fresh flour and water. This dilutes the acids already in the starter, so the acidity temporarily decreases. As a result, the pH rises from a very acidic level (around 3.7-4.0) to a more neutral range (around 5.8-6.0).

This is completely normal and actually important. The higher pH gives the yeast a chance to reproduce more efficiently, while the acid-producing bacteria slow down for a while. Over time, as the starter ferments, the acidity gradually builds up again.

This reset is why feeding timing is especially important. Feeding is not just maintenance. It is an intentional reset of the balance between yeast, bacteria, acidity, and available food.

Ingredients & tools for feeding your starter

• Sourdough starter
• Sourdough starter container with a lid: I usually keep my starter in a repurposed jar. Read more about the best sourdough starter jar.
• Kitchen scale: This is my favorite gram scale for feeding my starter.
• Flour: Use unbleached bread or all-purpose flour. Organic flour is a great choice. I use King Arthur Organic Bread Flour.
• Water: Use filtered, spring, or non-chlorinated water at room temperature. Avoid tap water with chlorine. To dechlorinate your water, leave it in an open container on the counter overnight.
• Jar spatula: This is my favorite jar spatula that fits perfectly in a 6-oz. sourdough jar.

How to feed sourdough starter step-by-step

Feeding your sourdough starter includes three basic steps:

1. Discard: Remove a portion of your starter.
2. Feed: Add fresh flour and water to nourish your starter.
3. Let it rise: Look for bubbling, rising, and a pleasant aroma.

Step-by-step starter feeding routine

• Prepare your jar: Start with a clean, empty jar. Weigh the jar (in grams) using a kitchen scale, then record the weight of the empty jar in your sourdough log or on the bottom of the jar.

• Transfer the starter: Stir your existing sourdough starter with a jar spatula. Then, transfer 5g of starter into the clean jar. Record the weight of the jar with 5g of starter (base weight) and highlight it in your log.

• Feed the starter: Add 25g of water and stir well. Then, add 25g of flour and stir until the mixture is thoroughly combined. Cover the jar loosely and place it in a warm location at 75-79°F (24-26°C). Remember to mark the starter's level with a rubber band to track its rise.

• Let it rise: Check the starter periodically for signs of activity, such as bubbles and increased volume, usually visible within a few hours. Record the time it takes to reach its peak in a sourdough starter feeding log.

Why sourdough starter rises and falls

Every healthy sourdough starter naturally goes through a feeding cycle (one complete loop) where it rises, reaches its highest point (peak), and falls. This process occurs because the wild yeast and bacteria in the starter work.

When you feed the starter, you provide it with fresh flour and water, which supply the yeast and bacteria with sugar and starch to eat.

As they eat, they produce carbon dioxide gas, which creates bubbles inside the starter. Over time, acidity builds as sugars are consumed, and the starter eventually reaches its maximum volume, called the sourdough starter peak.

However, once the yeast and bacteria have eaten all the food, yeast activity slows, acidity continues to rise, and the structure begins to weaken. The starter then collapses, signaling the end of that feeding cycle.

Active feeding vs paused fermentation

There are two fundamentally different feeding approaches to maintaining your starter: active feeding and paused fermentation.

Active feeding is when you keep your starter at room temperature and allow it to go through its natural rise and peak cycles before feeding. This method is used for regular baking and requires careful attention to timing.

A room-temperature starter usually needs feeding once a day. A good rule of thumb is a 1:5:5 ratio: one part starter, five parts flour, and five parts water.

Here is your daily feeding routine:

• Discard: Place the jar on the scale. Discard a portion of the starter until it returns to the base weight.
• Feed: Add 25g of water and 25g of flour. Mix well.
• Let it rise: Look for signs of bubbling, growth, and a pleasant aroma.
• Repeat daily, maintaining a 1:5:5 feeding ratio.

If you prefer to feed your starter twice daily (morning and evening), consider using a 1:3:3 ratio (one part starter, three parts flour, and three parts water) instead.

Please note that these feeding ratios and schedules are only guidelines. You have to learn how your own starter behaves and adjust the number of daily feedings and feeding ratios to match your sourdough goals.

Top tip: You don't need to change jars with every feeding. But cleaning your jar at least once a week helps keep unwanted bacteria from affecting your starter (see my guide to bad sourdough starter).

Paused fermentation happens when a starter is fed, and then fermentation is intentionally slowed or stopped, for example, by bringing the starter into the fridge. This is common when you bake less frequently and feed your starter once a week.

Problems arise when you unintentionally mix these two approaches. Read my guide on how to store sourdough starter to understand whether your starter should stay active or be paused. This helps prevent a weak, acidic sourdough starter and even loss of strength.

When should you feed sourdough starter?

Starter fermentation speed depends on room temperature, flour type, hydration, and starter strength. Two starters fed at the same time will peak hours apart, even when treated the same.

Key guideline: Feed your starter at peak or early collapse. This timing keeps the yeast active, sugars are mostly consumed, and acidity hasn't become excessive.

Once ready to feed your starter, pay attention to what the starter is doing:

• Has it risen significantly?
• Is the surface domed or starting to flatten?
• Does it smell mildly tangy or sharply acidic?
• Has it begun to collapse?

Avoid feeding too early, while the starter is still rising. Repeated interruptions weaken the starter and create imbalances. Think of it like letting your starter finish its "meal" before giving it more food.

Sourdough starter peak is the maximum height the starter reaches. At this point, sugars are nearly consumed, and acidity is higher. Many mature starters peak around pH 3.8-3.9, which is normal and healthy.

Early collapse begins when the starter starts to fall. It is still a safe feeding window.

How often should you feed sourdough starter?

Select a feeding schedule that naturally fits into your daily routine. If you have work or other commitments, consider feeding your starter once a day, either in the morning or in the evening. Try to stick to the same time each day to build consistency and avoid stressing your starter.

If you want to bake show-stopping loaves or grow your skills to sell sourdough bread, consider feeding your starter twice a day, once in the morning and again in the evening.

As a Cottage baker, I feed my starter twice daily. This provides it with sufficient food and maintains it in optimal conditions, allowing it to stay strong and active.

I also use the Brod & Taylor Sourdough Home to maintain a steady temperature of 75°F (24°C). This helps me avoid the ups and downs of seasonal temperature changes and eliminates the need to adjust my starter feeding ratios constantly.

If you don't bake often, store your starter in the fridge. This way, you only need to feed it once a week to keep it healthy and ready when you need it.

How much should you feed your starter?

While the 1:1:1 feeding ratio is widely advisable online, it is not sufficient to keep your starter strong and healthy, especially if you feed it only once or twice a day.

Feeding your starter at a 1:1:1 ratio means it is underfed. Over time, this weakens your culture, leading to sluggish fermentation and an overly acidic, less active starter.

Aim for at least a 1:5:5 ratio (one part starter, five parts flour, and five parts water) if you feed once daily at room temperature. This provides your starter with sufficient food to remain vigorous and thrive.

These feeding ratios are meant as suggestions, not strict rules, as each starter is different and depends on water temperature, flour type, room temperature, and humidity.

During summer baking, consider increasing the feeding ratio once or twice daily to adjust to the warmer temperatures, but observe the starter's behavior.

Here is another table showing feeding ratios based on how often you feed your starter.

Feeding Ratio	Feeding Frequency
1:1:1	Every 4 hours
1:2:2	Every 8 hours
1:3:3	Every 12 hours
1:4:4	Every 16 hours
1:5:5	Every 20 hours

What is a hungry starter?

A hungry sourdough starter has run out of food, meaning the wild yeast and bacteria have consumed the available sugars in the flour. This is what happens when you feed your starter with a 1:1:1 ratio once or twice a day.

Before each feeding, check the so-called "snail trail" left by the starter on the sides of the jar. This mark is left behind as the starter rises and falls when it runs out of food.

If the starter completely collapses by its next feeding time, it is time to adjust its feeding schedule or ratio. For example, if you are feeding it a 1:2:2 ratio twice a day and it still collapses before the next feeding, try increasing the ratio to 1:3:3.

Watch for the starter to peak and then only slightly deflate, forming a flat top instead of full collapsing. If this is the case, stick with that feeding ratio. If it has not yet peaked by the feeding time, decrease the ratio to 1:2.5:2.5 and observe.

Other signs of a hungry starter, when neglected for a prolonged period, include a strong, sour smell that may be unpleasant and a thin layer of liquid on top, known as hooch.

Sourdough starter maintenance tips

• Smell your starter before each feeding. A strong acidic odor indicates excessive acidity, which can help you troubleshoot and prevent baking mishaps.

• Use a kitchen scale to accurately measure the starter, flour, and water, as feeding ratios are based on weight, not volume. It is important to note that volume and weight differ. One cup of flour doesn't weigh the same as one cup of water.

• Always feed the starter with at least the same amount of flour and water (a 1:1:1 ratio) as is already in the jar after discarding, or even more. Never feed it less flour and water than in the jar. In short, avoid using a 1:0.5:0.5 ratio when feeding your starter!

• Feed your starter either at peak or just after. Avoid feeding it before it reaches its peak, as this dilutes and weakens the yeast colony.

• Avoid neglecting your starter for too long. Otherwise, the acid will accumulate, and you will continue to pass it into your next feed. Over time, it will result in a weak, acidic starter.

• When maintaining your established starter, set aside the discard for use in discard recipes, or use a no-discard method to maintain your starter.

• If you choose to dispose of the sourdough discard, avoid pouring it down the drain to prevent potential clogs over time. Use a spatula to discard the excess in the trash or compost bin instead.

• Before washing, wipe down the spatula and the empty jar with a paper towel.

• You can use a fresh jar daily or stick to the same one for daily feedings, as many bakers prefer continuity in the same jar.

• For optimal mixing, add water to the starter first, then add the flour. This allows the water to distribute evenly and hydrate the flour.

• After each feeding, scrape down the sides of the jar with a jar spatula and wipe the rim clean with a paper towel.

• Make feeding your starter part of your daily routine, but if you miss a feeding occasionally, your starter will survive.

FAQs

Due to numerous questions about feeding and maintaining a sourdough starter, I wrote a dedicated post answering the most common sourdough starter FAQs.

Here are a few more frequently asked questions and answers.

Let's talk sourdough

How often do you feed your sourdough starter? Have you tried different feeding schedules? I'd love to hear your experiences and tips in the comments below.

Ready to keep learning?

Now that you know how to feed your starter, let's take a closer look at what goes into it. Understanding the sourdough starter ingredients is key to building a strong, bubbly culture.

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