Sourdough Starter : Everything You Need to Know

Having trouble with your sourdough starter? Find everything you need to know to understand the basics of sourdough. Starter care, discard, sourdough terminology, and more.

When I first started with sourdough I had a lot to learn along the way. All the different types of starter were confusing, and a whole new vocabulary of terminology had to be created. As I’ve now helped many others begin their sourdough journeys, I’ve received many texts at all hours of friends and family who are afraid they’ve killed their starter, don’t know what to do next, or want to know how to tell if their starter is ready for baking bread.

In this post I’ve included much of the information I share in my Introduction to Sourdough HomeKeeper class. I hope you find it as a helpful resource in answering your questions no matter what stage of the sourdough journey you are in.

Sourdough Basics

What makes sourdough different than regular bread?

To begin to understand sourdough, we need to clarify the most simple basics of baking bread. In its most primitive form, bread is a combination of flour, water, and yeast. Of course, there are limitless combinations and additional ingredients that go into bread baking, such as sugar, salt, oil, herbs, etc. , but the foundation is always those three ingredients.

Flour and water should seem be pretty self explanatory. Flour is a grain that has been ground into a powder (typically wheat), and water is the good old H2O found in nature. While we could dive into flour a whole lot deeper, thats not the point of this post. We’re here to focus on sourdough. Sourdough, is all about that third ingredient. The yeast!

Yeast

What is Yeast?

Here’s how Merriam Webster defines it:

: a yellowish surface froth or sediment that occurs especially in saccharine liquids (such as fruit juices) in which it promotes alcoholic fermentation, consists largely of cells of a fungus (such as the saccharomyces, Saccharomyces cerevisiae), and is used especially in the making of alcoholic liquors and as a leaven in baking

: a commercial product containing yeast fungi in a moist or dry medium

: a unicellular fungus that is present and functionally active in yeast, usually has little or no mycelium, and reproduces by budding

: any of various similar fungi

: something that causes ferment or activity

For the sake of this article, we are going to define yeast as a tiny living microorganism that eats flour and produces CO2 gas bubbles.

Most people are largely unaware of the impact yeast has in their everyday life. When I started my sourdough journey, one of the first things I learned was that yeast is EVERYWHERE! In the air, on your counters, on your skin, in your body, in our food…everywhere!

Different Strains of Yeast

Similar other organisms, yeast comes in many different “varieties” or “breeds”. The term we use for this with yeast is a “strain”. Just like flowers or dogs, yeast also has wild varieties and some that humans have cultivated, or domesticated, if you will. I’m confident we could all identify a wild flower, or a wild dog, from their counterpart because each has distinct characteristics. Stains of yeast are no different.

My first encounter with different strains of yeast, was while working at a vineyard and winery in college. To urge different flavor profiles out of the grapes, you inoculate different grape varieties with different strains of yeast. It’s all extremely fascinating for the chemistry minded, but I digress.

Some common types of yeast that you may be familiar with are bakers yeast, brewers yeast, wine yeast, and wild yeast. For sourdough, the latter is our friend.

What is wild yeast?

“Yeast is a living microorganism that feeds on carbohydrates and releases carbon dioxide and alcohol. Wild yeast of the genus Brettanomyces is found in the natural world and can be easily captured from plants, animals, your home, and even your skin. A sourdough starter or yeast starter for beer captures the wild yeast, and the yeast releases carbon dioxide and alcohol that helps to leaven bread and enable fermentation. “(https://www.masterclass.com/articles/wild-yeast-guide)

The process of making a sourdough starter is simple. Capture these wild yeast from the environment, and cultivate them until their population is great enough to product the necessary rise for bread.

If you’ve gone through the process of starting a starter from scratch, that is what you have done. If you received a sample of starter from a catalog or friend, they’ve already done that work for you.

Here’s the kicker though. Because every environment has different conditions, your strain of wild yeast captured at your house may be different that your friend, relative, or a manufacturer. That’s what makes the flavors even within the umbrella of sourdough so vast.

Perhaps you’ve heard someone say, “So and so has a good starter.” It doesn’t mean another starter is bad or has gone bad, but rather that whatever strain that person has cultivated produces a desirable flavor and texture. Just like I learned from making wine.

Sourdough Starter

The very first thing you will need to begin baking sourdough bread is a sourdough starter. Just like you would add packaged bakers yeast to a recipe, your starter contains the yeast you need to add to your recipe in sourdough baking.

There are many ways to attain a sourdough starter. You can purchase one, get one from a friend, or cultivate one yourself.

Feeding Your Starter

I’m going to assume for the remainder of this post that you already have a sourdough starter. To keep your starter alive and ready to use, you will have to do regular basic care. We call this “feeding” your starter. By adding a mixture of flour and water you provide the nutrients and environment for yeast to thrive. Just like every living thing, eventually they’ll eat up all the food you give them, and will need more.

How to Feed A Sourdough Starter

Many different opinions and methods exist for feeding sourdough. Believe it or not, the combination of three basic ingredients is not as straight forward as you may first assume.

Flour

The first decision is what type of flour you are going to feed your starter. Some choose fresh milled, gluten free, wheat, rye, and on and on. Personally I use unbleached wheat flour from the store. I have tried whole wheat, but have the best luck getting the flavor I want from the plain stuff. The most important thing to note, in my opinion, is the UNBLEACHED. Household bleach is a strong chemical and it kills little organisms (AKA germs). That’s why it makes a great disinfectant. However, we are wanting to grow little organisms, so unbleached is the way to go.

Water

Since we’re talking about bleach (often chlorine based) it’s also important to note that most public water services also use chlorine as an additive. For sourdough you want to avoid using chlorinated water in feeding your starter. Some choose to run their water through a countertop filter (such as a Berkley) or under-the-counter reverse osmosis system. You can also choose to purchase bottled water, preferably spring or distilled. I at times will use bottled water, however, we have a well so I most often just use tap water that has run through our whole home filtration system.

Hydration

Once you have your flour and water, it’s time to do the feeding. What ratios of flour, water, and starter you choose to mix together will determine the hydration of your starter. This hydration is measure in a percent, so the more watery your mixture is the higher the hydration percentage.

I like to use an equal part feeding. Which means I take equal amounts of starter, flour, and water and mix them all together. Some prefer to do this meticulously on a scale, others measure by volume, and some just eyeball it. (I fall in that category.). Other ratios are used by various bakers, as low as just 10% of the mixture being starter and the remaining 90% being comprised of flour and water.

If you are familiar with sourdough, you may want to take it even another step further and look into a “dry” starter like the one used on The Elliot Homestead.

Frequency of Feeding

The final piece in feeding your sourdough starter is the frequency of feeding.

Keep in mind that warmer yeast organism will be more active and therefore eat more than a cold yeast organism would. If you take your wild yeast all the way down to freezing temperatures you can keep it alive in storage for up to a year. I wrote a whole post on freezing sourdough starter if you want to learn more about storage in teh freezer. However for this post we are talking about starter that you are wanting to use in baking.

At room temperature your starter will need to be fed more often than one that is cooler. That cooler temperature may be a result of the fridge, but even within the rooms of your home the temperature will vary throughout the year.

Typically a starter stored at room temperature (68-72 degrees F) will need fed once every 24 hours. Try for a consistent schedule of every morning, or every night. However, if you want to encourage your starter to be very active you may want to feed it every 12 hours to be sure feeding is not the limiting factor to achieving a great rise.

What is Rise?

Since I mentioned it, let’s take a quick rabbit trail. Rise is how much your sourdough starter increases in volume after a feeding.

Try putting a rubber band around your start jar right after a feeding. Check back every few hours to see how the starter will RISE up in the jar, ideally doubling in volume (or more) from the gas bubbles trapped in your mixture. Eventually it will fall again as that CO2 is released. The bigger the increase in volume AKA the bigger the rise, and the quicker it can get there is an indicator of the health of your starter. More yeast living and active in your starter means this process will happen quickly and more dramatically than if your yeast population is small or struggling.

Sourdough Storage

I’ve already mentioned storing your sourdough starter in the section above, but let’s take a quick minute to dive into that concept a little deeper.

Refrigerator Storage

Perhaps you like to bake regularly, but keeping up with daily maintenance on a starter just doesn’t fit into your lifestyle. Maybe you are going on a vacation or want to take a little baking break for a few weeks. These situations call for the convenient option of refrigerator storage.

You can easily tuck your sourdough baby in for a nice little nap in the back of the fridge, and come back to it when you’re ready or able. Here’s how to do it!

1. Feed your starter a normal feeding
2. Wait about an hour (for the yeast to get their little bellies full)
3. Tuck them into the fridge.

In a week or two when you are ready to bake again, bring your starter to room temperature and feed as usually. I recommend two feedings to revive it before using your starter for baking again.

If you aren’t ready to bake, after feeding it, just tuck it back into the fridge for next week. It’s that simple.

Drying & Freezer Storage

Head over to my post on drying and freezing sourdough starter for all the specifics on this storage method.

Sourdough Discard

Discard, active starter, starter…. I’m confused!

It can be confusing to sift through what stage of the sourdough cycle your recipe is calling for. I treat my starter differently depending on what I want to do with my starter in the near future. Do I want to bake? Maybe I want to put my sourdough away for a busy season of life, or cut back on the amount of starter I’m maintaining.

What is an “active” starter?

An active starter has been recently fed, and has sufficient yeast activity to create the necessary rise.  It will be bubbly and smell yeasty.  Warmer temperatures encourage the yeast activity, so a cold starter taken from the fridge needs to warm up and be fed to reactivate.

You want to use active starter in recipes that are calling for the wild yeast to do the rising (such as a loaf of artisan bread). Look for recipes that don’t have another rising agent, like baking soda or baking powder.

What is a “dormant” starter?

I consider a dormant starter one that has not been fed in a long while and the organisms have been in an environment that has encouraged sloooww feeding and reproduction. Perhaps it’s been in cold storage (aka fridge or freezer) and has not had much activity going on for quite a while. Dormant starter will need multiple feedings at room temperature to get it back up and running as an active starter.

While there are still yeast present and alive, I wouldn’t use it for baking in recipes that don’t have another leavening agent.

What is sourdough discard?

Discard is starter that is no longer active.  The yeast have consumed the nutrients in the flour, and have moved past their peak performance.  The flour has been fermented, and the yeast have slowed reproduction or begun go dormant or die.   You don’t need to “discard” it. Sourdough discard can be used in a various recipes, you will just need to provide an alternate leavening agent (baking soda or powder) if you want a “rise”.

I have written an entire separate post just on sourdough discard. Be sure to head over there to get your questions answered!

Help! I think I killed my sourdough starter!

It’s very unlikely you will “kill” your starter.  Even with significant neglect a sourdough starter can be brought back around with a little tender loving care. Even if you find your sourdough starter not rising, here are some things to look for:

Bubbles

As long as you see bubbles, your starter is alive.

Hooch

Hooch is a watery layer that will form on the top of your starter.  There is nothing wrong with it, you can choose to drain it off or stir it back in.  If left long enough the hooch will turn greyish-black.  The starter still isn’t dead or bad, it’s just starving.  If hooch is developing, you probably aren’t feeding your starter enough.  Try feeding a larger ratio of flour and water with less starter, or if you’re developing hooch while storing in the fridge (which is common) just be sure to take it out every week or so and give it a nice feeding before tucking it back in the fridge again.

Mold

Black spots or white fuzzies are indication that your starter has gone bad and another organism that you don’t want (such as mold) has permeated your starter.  If this happens, throw it out and start again.