Nov 27, 2023

How To Keep Your Sourdough Starter Warm

It's that time of year when it can be challenging to keep your sourdough starter warm - this can make a HUGE difference in the quality of both your starter and the outcome of your bread.

In fact, temperature can be the difference between a sourdough starter that rises and one that doesn't. Ideally you want to keep your sourdough starter warm, so that it functions in any weather, even the depths of winter.

This post shares why it is important to keep your starter warm, and a few different methods for keeping your sourdough starter warm and thriving, even in a cold climate.

Why Does A Sourdough Starter Need Warmth?

Sourdough starter requires a warm ambient temperature to ensure that the wild yeast stay active and the fermentation process occurs. Sourdough yeast will hibernate and become inactive if the temperature is too cold. This means your sourdough starter will not rise and double and thus your sourdough loaves will also be flat and dense.

A sourdough starter requires a warm ambient temperature rather than direct heat - direct heat will cause your sourdough starter to cook and eventually kill your starter.

What Is The Ideal Temperature For Sourdough Starter

For the healthiest sourdough starter, you want to keep it between 75-82F.

Temperatures outside of this range won't necessarily kill your sourdough starter, but they can result in a sourdough starter that is under or over active.

And remember, the health and activity of your sourdough starter directly affects the quality of your bread.

So How Can You Keep Your Starter Warm in the Winter?

Some of the most popular and effective ways to keep an active sourdough starter warm include:

Feeding your starter with warm water - If your sourdough starter needs some extra warmth, simply feeding it with warm water can help to increase its overall temperature.
Keeping it in your microwave or oven with the light turned on - Keeping your sourdough starter in the oven can be a littler dangerous because it's an easy way to cook it if you (or someone else) turns the oven on without realizing your starter is in there - I've done this! However, if you can ensure this doesn't happen, keeping your sourdough starter in the oven with just the light on can create a warm, stable environment for your starter to thrive.
Heating pad/mat - heating mats are also suitable for keeping a sourdough starter warm. I've heard great things about these Fermentation Heating Pads.

What Temperature Kills Sourdough Starter?

Yeast will die if exposed to temperatures above 120F - this would be considered too hot for a sourdough starter and will kill the wild yeast if exposed for long periods.

How Long Can I Leave Sourdough Starter At Room Temperature?

As long as you're feeding your sourdough starter, it should survive at room temperature indefinitely.

A younger sourdough starter will need to be fed more regularly than a mature and active sourdough starter when left at room temperature. A mature sourdough starter may survive at room temp without being fed for several days. A new starter requires twice daily feeding or it will more than likely go moldy.

Regardless of the age or maturity of your culture, regular feeding is essential for a healthy sourdough starter! I recommend feeding it daily at room temperature, and at least every seven days in the refrigerator.