Here's How To Freeze Leftover Starter To Make A Shortcut Sourdough Bread Later

Making sourdough bread is a labor of love — a multi-step process that builds rich flavor through the fermentation of wild yeast interacting with the proteins of flour. Few things beat the satisfaction of turning a few simple ingredients into homemade sourdough bread. But keeping a starter alive, let alone making one from scratch, can be tricky, especially if you travel or have other responsibilities that interfere with the process of feeding the waiting yeast. But Nathan Myhrvold, Founder of Modernist Cuisine and lead author of "Modernist Bread" has developed a process for saving your starter that could be a game changer.

He suggests freezing the excess starter in an ice cube tray to allow you to hold it for up to two months. Unfed starter can tolerate about a week in the fridge, so freezing gives you a much longer opportunity to use the starter. However, the yeasts and bacteria that fuel the beautiful rise of your bread will not survive, but the flavor will be there, sort of like a bouillon cube for bread. With the frozen starter cubes, some fresh yeast and your dough recipe, you'll get a loaf of what Myhrvold calls second-chance sourdough.

The main point of these frozen starter chunks is adding the flavor of ripe sourdough starter to your bread. When you make bread in the usual way, those long proofing times allow the lacto-bacteria and yeast to ferment, which is the source of the delicious tanginess in a sourdough loaf. Although the yeast and bacteria in the starter only survive about two weeks in the freezer according to Myhrvold, the flavor lives on. By adding fresh yeast along with the defrosted starter you'll have a much quicker proof, meaning a faster end loaf of bread thanks to the action of the added yeast. Yet you'll also still get good sourdough character.

To put this trick into use, Myhrvold recommends using the same weight of thawed starter that you'd use in your sourdough recipe normally. To find the amount of extra yeast needed use the baker's percentage method. Myhrvold's recipe uses 0.8% yeast, or roughly 4 grams for a loaf starting with 480 grams of flour plus 10 grams of wheat bran. Freezing your starter means you'll never need to miss out on the flavor of sourdough again.