A sourdough starter is a mixture of flour and water that captures natural wild yeast and beneficial bacteria from the environment. It replaces commercial yeast and is responsible for the rise, flavour, and texture of sourdough bread.

Sourdough is naturally leavened, meaning it contains no commercial yeast. Instead, the starter produces carbon dioxide for rise and lactic acid for flavour. This is what gives sourdough its signature structure, depth, and slightly tangy taste.

With proper care, a sourdough starter can last for years.

As long as it is regularly fed and maintained, it will remain active and ready to bake with at any time. However, a neglected starter can weaken or develop mold or harmful bacteria. If contamination occurs, it must be discarded.

Yes. Our sourdough starter is a mature, established heirloom culture, which means it becomes active and reliable much faster than creating one from scratch.

Our step-by-step rehydration guide walks you through the process in just a few minutes per day over 7 days.

A sourdough starter can be used indefinitely.

As long as you continue feeding it, you can bake bread, pancakes, cookies, waffles, and more. There is no limit to how much you can make—it is a continuous culture.

Rehydrating a dehydrated sourdough starter typically takes 7–8 days.

During this process, the starter is gradually fed flour and water until it becomes active, bubbly, and strong enough to bake with. Detailed step-by-step instructions are included with every Summit Sourdough starter.

Flour quality is one of the most important factors in sourdough success—the higher the quality, the better the results.

For best results, use a high-protein white bread flour, ideally 13–14% protein, as the protein feeds the culture and supports strong fermentation.

We recommend Great Plains Strong Bakers Flour, available at Costco, for consistent, high-performance results.  

If needed, a high-quality all-purpose flour with similar protein content can be used. Avoid whole wheat or rye during rehydration, as they can slow development.

Tap water or bottled drinking water works best, as they contain the minerals needed for fermentation.

If your tap water is highly chlorinated, let it sit out overnight to allow the chlorine to dissipate. Avoid distilled or reverse osmosis water, as they lack the minerals needed for a healthy starter.

Your starter should be thick—similar to cold honey.

A mixture that is too runny will not be able to rise properly.  A properly fed sourdough starter uses a scale for precision.  View our article on sourdough starter feeding ratios.   

It is normal for a sourdough starter to take several days to become active during rehydration.  Stay away from no-name brand store flours that are full of additives and other bleaching agents like chlorine.   We have a full article on the different types of flour and what works well.    

The most common causes of poor activity are related to flour quality and feeding practices.

• Low-protein or low-quality flour
• Feeding by volume instead of weight
• Incorrect consistency that is too thin
• Inconsistent feeding schedule
• Trying to artificially heat the starter

There is no need to use heating pads or warm environments like ovens. Too much heat can damage the culture and encourage harmful bacteria. Your starter will perform best at room temperature.

A sourdough starter that smells like vinegar or acetone is usually hungry and needs to be fed.

As the yeast and bacteria consume available nutrients, they produce stronger acidic byproducts, creating that sharp smell.

To fix this, discard a portion, feed fresh flour and water, and continue consistent feeding. For best results, use a 1:2:2 or 1:3:3 feeding ratio by weight in grams. 

A sourdough starter that smells badly can signal that there's not enough food or it's not being fed regularly.

The liquid on top of your starter is called hooch, and it is completely normal.

Hooch forms when the starter has consumed its food and begins producing alcohol as a byproduct. It may appear clear, grey, or darker in colour.

You can pour it off for a milder flavour or stir it back in for a more sour flavour. Then discard a portion and feed your starter fresh flour and water.  To prevent hooch from forming frequently, maintain a consistent feeding schedule every 24–36 hours at room temperature, or store your starter in the fridge if you’re not baking regularly.

A sourdough starter should be fed every 24–36 hours at room temperature.  If you are not baking regularly, check out our guide on how to store your sourdough starter in the fridge properly

If you are not baking regularly, you can store your starter in the fridge. Feed it, refrigerate it to slow fermentation, and then resume regular feedings before baking. 

Consistency is key to maintaining a strong, healthy starter.

If your starter is close to exploding over the top of the jar feel free to use a rubber spatula to mix it down.  Stirring it to knock the air out will cause the starter to deflate down to about where the elastic is.  Keep in mind, that your starter will continue to grow until it's done feeding on the flour.  This can typically last anywhere from 6 to 12 hours depending on the environment in your house.  I suggest you keep your starter jar on a plate to catch any overflow.   This though, is a coveted right of passage in the sourdough  world, to have a starter so active it blows over the top of your jar.   Expect that with Summit Sourdough

Both starters are  our strong and established heirloom sourdough culture. The difference is in the flour used to maintain them—organic versus bread flour.  Our Organic Sourdough Starter is maintained with a high quality Organic All Purpose Flour and our Regular Sourdough Starter is Maintained with Great Plains Strong Bakers Flour.

Choosing the correct size depends on the type of bowl or brotform you’re using.

Regular Size Covers

• Best for standard mixing bowls
• Ideal for our round brotforms
• Fits most common kitchen bowls used for sourdough mixing and proofing

Extra Large Covers

• Designed for oval brotforms
• Best for larger bowls, including KitchenAid mixer bowls
• Provides more room for dough expansion during proofing

While the regular size can fit oval brotforms, it will be a snug fit. For easier use and better coverage, we recommend choosing the XL size for oval shapes.

If you’re unsure, sizing up is often the best option to ensure a comfortable fit and proper coverage.