Sourdough Starter Feeding Ratios for Hot Weather

Sourdough feeding ratios are written as three numbers: starter, flour, and water. All three ingredients are measured by weight.
A ratio of 1:1:1 means:

• 10 g sourdough starter
• 10 g flour
• 10 g water

A ratio of 1:3:3 means:

• 10 g sourdough starter
• 30 g flour
• 30 g water

A ratio of 1:5:5 means:

• 10 g sourdough starter
• 50 g flour
• 50 g water

The first number is the amount of mature starter carried into the next feeding. The other numbers show how much fresh flour and water it receives.
Increasing the ratio does not make the starter weaker. It gives the microorganisms more food and lowers the percentage of old, acidic starter in the mixture. As a result, the starter usually takes longer to reach its peak.

At a comfortable room temperature, a 1:1:1 feeding can be useful when you need an active starter quickly. In a hot kitchen, however, that small amount of food may be consumed within only a few hours.
The starter may double, flatten, and begin falling before you are ready to mix your dough. If it remains collapsed for many hours, it can become very acidic, thin, and strongly scented.
This does not mean that 1:1:1 is a bad feeding ratio. It simply has a short fermentation window in warm conditions. It is best used when you plan to watch the starter and use it soon after feeding.
For routine maintenance, overnight feeding, or a long workday, a larger ratio is usually more convenient.

The following chart is a practical starting point for a mature, active starter kept at 100% hydration. Your starter may ferment faster or slower depending on its strength, flour, water temperature, and the actual temperature inside the jar.


These ratios are not strict rules. They are starting points that can be adjusted after observing when your starter reaches its peak.
If the starter peaks too early, increase the ratio at the next feeding. If it is still far from its peak when you need it, use a smaller ratio.

When you plan to mix dough later the same day, choose a feeding ratio based on how many hours you have available.
In a warm kitchen, a strong starter fed at 1:2:2 may be ready within several hours. A 1:3:3 feeding generally gives you a little more time, while 1:5:5 is more useful when the starter needs to wait through most of the day.
For example, if you want to mix dough in the afternoon, you might feed:

• 10 g starter
• 30 g flour
• 30 g water

Mark the starting level on the jar and watch the starter rather than relying only on the clock. Use it when it has expanded well, contains bubbles throughout, and has a slightly domed or level surface.
If the surface has become deeply sunken and streaks are visible above the starter, it has already passed its peak.

Overnight feeding is often the most difficult part of summer starter care. A small feeding may peak in the middle of the night and remain hungry until morning.
At 24–26°C (75–79°F), try beginning with 1:3:3 or 1:5:5. In a hotter kitchen, 1:5:5 or 1:10:10 may fit an eight- to twelve-hour night more comfortably.
A small overnight feeding could be:

• 5 g mature starter
• 50 g flour
• 50 g water

This is a 1:10:10 ratio and produces 105 g of starter. It provides plenty of food without creating a large amount of discard.
Check the starter in the morning. If it has already risen and completely collapsed, use less mature starter or a larger feeding ratio next time. If it has barely risen, try 1:5:5 instead.
Cool water can also help extend the fermentation time, but the feeding ratio should remain the main adjustment.

Some bakers avoid ratios such as 1:5:5 because they assume they must maintain a huge jar of starter. The ratio can remain large even when the total quantity is small.
For example:

• 5 g starter + 25 g flour + 25 g water = 55 g starter
• 5 g starter + 50 g flour + 50 g water = 105 g starter
• 3 g starter + 30 g flour + 30 g water = 63 g starter

Keep only the amount you need for the next feeding or recipe. A digital scale that measures individual grams makes this much easier.
When preparing starter for bread, calculate how much the recipe requires and build only that amount, with a little extra left for maintaining the culture.

The chart assumes a typical wheat starter, but flour can change the rate of fermentation.
Whole-wheat and rye flour often make a starter peak faster because they provide abundant minerals and nutrients. A starter fed with a large percentage of whole-grain flour may need a higher feeding ratio than one fed entirely with white flour.
If your starter races through a 1:5:5 feeding in hot weather, you can replace part of the whole-grain flour with bread flour or all-purpose flour. You can also increase the ratio slightly.
Make only one adjustment at a time. If you change the ratio, flour, water temperature, and hydration together, it becomes difficult to understand which change produced the result.

A healthy, established starter can usually handle ratios such as 1:5:5 or 1:10:10. A new or weak starter may respond differently.
If the starter rises poorly, contains only a few bubbles, or needs more than a day to show activity, feeding it at 1:10:10 may dilute it too much. Begin with 1:1:1 or 1:2:2 until it becomes stronger and more predictable.
Large ratios are useful for managing an active starter, not for forcing a weak starter to become active.
Once the starter rises reliably after several feedings, gradually increase the ratio to match the warmer temperature.

The correct feeding ratio allows the starter to reach its peak close to the time you want to use or feed it again.
The ratio may be too small if the starter:

• Peaks and collapses many hours before the next feeding.
• Becomes runny soon after rising.
• Develops a strong acetone or sharply acidic smell.
• Frequently forms liquid on the surface.
• Needs repeated feedings to recover before baking.

The ratio may be too large if the starter:

• Takes much longer than expected to rise.
• Shows only limited activity before you need it.
• Fails to reach a strong peak despite being healthy before feeding.

Adjust the ratio gradually. Moving from 1:1:1 directly to 1:10:10 may create more confusion than useful information. Try 1:3:3, observe one or two feeding cycles, and then move to 1:5:5 if necessary.

There is no single perfect summer feeding ratio. The best ratio depends on the temperature and on when you need the starter.
If you are home and planning to bake soon, a smaller ratio can provide a quick peak. If you are leaving for work or feeding before bed, a larger ratio gives the starter enough food to last through the longer interval.
Instead of feeding automatically at the same ratio throughout the year, watch how the starter behaves. Record the kitchen temperature, feeding ratio, feeding time, and time of peak for a few days.
Soon you will have a simple summer schedule designed for your own starter. When the starter reaches its peak at the right time without spending hours collapsed and hungry, you have found the correct ratio.