Understanding the importance of a second build with your sourdough starter
Once you’ve done the first refreshment of your starter, you might be ready to bake something simple, like a tin loaf. However, if you’re planning to bake a more complex bread, such as a boule, you’ll often need to take your starter through a second refreshment, known as a second build starter.
What is a Second Build Starter, and why must you build it again?
The second build starter is essentially the next step in strengthening and invigorating your starter. After the first refreshment, your starter is more active than before, but it still might not be strong enough to provide the leavening power needed for breads that require more structure and complexity, like a boule.
By refreshing your starter a second time—feeding it with fresh flour and water—you’re giving the yeast and bacteria another boost. This second build is crucial for increasing the population of these microbes, making your starter more potent. A well-refreshed, active starter at this stage will rise more quickly, develop a fresh yogurt-like lactic sourdough smell, and have the strength needed to leaven a dough with more complex flavours and textures. You can learn more about the ingredients to build your starter here.
Why a Second Build is Important
The second build not only boosts the activity of the yeast and bacteria but also ensures that your starter has enough strength to carry through the entire fermentation process. For a boule, which requires the dough to hold its shape and develop an airy crumb, you need a starter that’s at its peak performance. This means it should be full of lively microbes that can work efficiently to produce gas and help the dough rise.
If you skip this second build and use your starter after just one refreshment, the dough might not rise as well, and the resulting bread could be denser and less airy. The second build gives your starter that extra push to perform at its best, ensuring your bread has the lift and structure you’re aiming for.
When a Third Build Might Be Necessary
Now, if your starter has been sitting in the fridge for more than three weeks without being refreshed, it may need even more care to get back to full strength. After a long period of inactivity, the yeast and bacteria in your starter will have slowed down significantly. In this case, a third build—another round of feeding—might be necessary.
This third refreshment gives your starter the extra time and nutrients it needs to become fully active again. You’ll know your starter is ready when it rises more rapidly and has a fresh, tangy, yogurt-like smell, which indicates that the lactic acid bacteria are healthy and active. At this stage, your starter is not only ready to bake a complex bread like a boule but also strong enough to be stored again in the fridge for another week or more.
Experience and Observation
As you become more experienced with sourdough baking, you’ll learn to recognise the signs of a healthy, active starter. You’ll notice how it looks, smells, and behaves at different stages of refreshment. Over time, you’ll develop a sense for when your starter needs another build or when it’s ready to bake with after just one or two refreshes. This intuition is key to successful sourdough baking, as it helps you adjust to the specific needs of your starter and the type of bread you want to make.
Maintaining a Healthy Starter
Keeping your starter healthy is crucial, especially if you’re storing it in the fridge between bakes. A very active starter, refreshed properly, is better equipped to survive longer periods in the fridge. When you take it out for your next bake, it will be easier to revive with just one or two refreshments, rather than needing multiple builds to get it back to strength.
See 1st build and 3rd build and How to Refresh a Sourdough Starter
