The Optimal Temperature Range for Creating Sourdough Starter

Sourdough starters are a magical concoction of flour, water, and the wild yeasts and bacteria present in our environment. This mixture, when kept in the right conditions, can lead to the creation of delicious bread with a distinctive tang. One of the most critical variables in this equation is temperature. But what exactly is the optimal temperature for fostering a thriving sourdough starter? Let’s explore.

Understanding the Basics

At its core, a sourdough starter is a living ecosystem. The yeast and lactic acid bacteria it harbors are sensitive to their environment, particularly temperature. Temperature affects the rate of fermentation, the balance between yeast and bacteria, and the overall health and activity of the starter.

The Optimal Temperature Range

The optimal temperature for sourdough starter is between 78°F (25°C) to 82°F (28°C). Within this range the balance between yeasts and lactic acid bacteria is maintained, ensuring that the starter has a pleasant tang without becoming overly sour. It also promotes a consistently active starter, allowing it to predictably double in size within 6-8 hours after feeding.

Cooler Temperatures (below 78°F / 25°C):

Pace of Activity: The fermentation process slows down considerably. This results in the starter taking longer to exhibit signs of life and to double in volume.

Flavor Profile: A noticeable shift occurs in the acids produced. Cooler environments foster the production of acetic acids. This type of acid gives the sourdough a pronounced sour bite, reminiscent of the sharp tang in vinegar.

Maintenance: One of the perks of a cooler environment is that the starter can be more forgiving with feedings. Its slower activity rate translates to less frequent feeding requirements.

Warmer Temperatures (above 82°F / 28°C):

Pace of Activity: A warm environment acts as a catalyst, accelerating the fermentation process. In such conditions, a starter can spring to life, becoming exceptionally bubbly and active in just a few hours.

Flavor Profile: The balance of acids shifts once more. Warm temperatures encourage the production of lactic acids. Unlike its sharper acetic counterpart, lactic acid imbues the sourdough with a milder, smoother sourness, akin to that of yogurt.

Maintenance: With great activity comes great responsibility. Starters in warm conditions are hungrier, requiring more frequent feedings. Neglecting this can cause microbial die-off, resulting in a weakened starter.

Tips for Temperature Regulation

  1. Use a Thermometer: Invest in a kitchen thermometer to check both the temperature of your starter and its environment.
  1. Water Temperature: You can slightly adjust the water temperature you use for feedings. Warmer water for cooler environments and cooler water for warmer environments.
  1. Innovative Locations: For a warmer spot, consider placing your starter near an oven with a pilot light, on top of a refrigerator, or inside an oven with just the light on. For cooler areas, basements or cellars can be perfect.
  1. Thermal Containers: Using an ice box or wrapping your starter in a cloth can help maintain a more consistent temperature.
  1. Commercial Proofing Boxes: These are controlled environments used for fermenting dough and can also be used for maintaining a starter’s temperature.


While the optimal temperature range for creating and maintaining a sourdough starter lies between 68°F and 78°F, it’s worth noting that starters are resilient. With a little attention and care, they can adapt to a variety of conditions. So, whether you’re in a chilly climate or the middle of a heatwave, with the right strategies, you can foster a thriving sourdough ecosystem. Remember, the journey with sourdough is as much about intuition and adaptability as it is about precision. Happy baking!


Hey there! I'm Sam, your go-to pal for all things sourdough. I've been baking and kneading for 10 fun-filled years, and I can't wait to share the joy of turning simple ingredients into heavenly sourdough bread with you. Grab your apron and let's dive into this amazing world of sourdough bread together on this blog.

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