Milk & Yogurt: Boosting or Busting Sourdough Starter?

The world of sourdough is one of tradition, science, and a touch of artistry. At its heart lies the sourdough starter – a mix of flour and water that captures wild yeasts and beneficial bacteria from the environment. But what if we veer from tradition and introduce dairy, like milk or yogurt, into our starters? The idea might sound unconventional, but it’s been explored by many adventurous bakers. Here’s a comprehensive look at the impact of incorporating dairy products into a sourdough starter.

While traditional sourdough starter consists of just flour and water, some people introduce dairy like yogurt or milk to jumpstart fermentation due to the existing bacteria. However, dairy can risk introducing unwanted microbes and may make the starter more perishable. It’s best to use dairy in the actual bread recipe, not the starter.

Introducing Dairy: Milk and Yogurt

1. Milk

Pros: Milk contains lactose, a sugar that can feed the lactic acid bacteria, potentially leading to a more vigorous fermentation and a creamier texture in baked goods.

Cons: Milk can also introduce other microbes that might not be beneficial to the starter. The fats in milk might go rancid over time if left out at room temperature. Moreover, a milk-based starter might require more frequent feedings.

2. Yogurt

Pros: Yogurt contains live active cultures, which can potentially boost the bacterial activity in your starter. This could lead to a tangier flavor profile.

Cons: The microbial balance of your starter might shift significantly, making it unpredictable. It might also make the starter more acidic, which can affect the final product’s taste and texture.

Potential Challenges of Using Dairy

1. Shelf Life

Dairy products can spoil over time, even when fermented. This can lead to a decreased shelf life for your starter.

2. Unwanted Microbes

Dairy can introduce new microbes to your starter that might compete with the natural yeast and bacteria, potentially leading to mold or other spoilage organisms.

3. Flavor Changes

The flavor profile of your sourdough will likely change, becoming tangier or even taking on a slight dairy note. While this might be desired by some, it might not be to everyone’s liking.

4. Maintenance

Dairy-based starters might need more maintenance in terms of feeding and temperature control.


1. Start Small

If you’re considering using dairy in your starter, try it with a small portion first. This allows you to experiment without compromising your entire batch of starter.

2. Maintain a Backup

Always keep a traditional water-flour starter as a backup. This ensures that you have something to fall back on in case the dairy experiment doesn’t pan out.

3. Refrigeration

To prevent spoilage, consider storing your dairy-based starter in the fridge and taking it out a day before you plan to use it.

4. Frequent Feedings

Given that dairy can introduce a plethora of new microbes, feed your starter more frequently to ensure that beneficial microbes thrive and prevent any potential spoilage.

5. Taste and Adjust

Remember, the introduction of dairy will likely alter the taste of your baked goods. Always taste and adjust your recipes accordingly.


Incorporating dairy products into a sourdough starter is a path less trodden, but it offers intriguing possibilities in terms of flavor and texture. While it comes with its own set of challenges, the results can be deliciously rewarding for those willing to experiment. As with all things sourdough, patience, observation, and a little bit of science will go a long way in ensuring success. 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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