How to Make and Maintain a Sourdough Starter (aka Levain)

I'm not entirely sure how it happened, but somewhere along the way I discovered and fixated on baking bread. Specifically, I'm referring to bread made in its purest form using only flour, water, and salt. I never cease to be in awe of how three humble ingredients can transform into one of the most delicious and comforting foods. In the interest of being overly dramatic, the fact that I made these with my own two hands is pretty magical.

"Slow bread" requires a sourdough starter (or levain) so that was my first project. Levain is a mixture of water and flour that has been converted into a leavening agent through the process of fermentation. Not only is microbiology+food fun, but you need to "feed" the levain regularly and it's apparently bad luck if you don't name it. So basically your sourdough starter is a food pet. (My starters are named "Moomin" and "NYoomin".)

When I first began caring for my sourdough starter, I was neurotic about feeding times and measurements. What a sweet and naive child I was in the days of yore. Creating and maintaining a sourdough starter is relatively straightforward. Once you get a feel for how your levain behaves, you'll develop a personalized approach.

This post streamlines what I've learned so you can create a fermented food pet to call your own. I'm happy to answer any questions about the process so just leave a comment.

The Fundamentals

I could travel down the rabbit hole on some of these topics, but in the interest of publishing this post before next year I'm going to try and get to the point.

What is a sourdough starter or levain?

Wild yeast are fungi and exist everywhere - in flour, on our bodies, and in the air. By fermenting water and flour, you're growing colonies of both wild yeast and "good bacteria" or lactobacilli. Here's the brief explainer:

  • Bacteria or Lactobacilli - The bacteria's main job is to turn your levain into an acidic environment. This acidity contributes to the sour flavor of your bread and, more importantly, prevents "bad bacteria" from taking hold. The most common question I've seen online is, "Why doesn't the starter make me sick after weeks on the counter?" The answer is bacteria. Counterintuitive but that's why science is awesome.
  • Wild Yeast - Commercial yeast can't hang in the above mentioned acidic environment so that's where wild yeast comes in. Not only does wild yeast thrive with the "good bacteria", but colonies of yeast give off carbon dioxide which contributes to the structure and rise of your bread. For the record, bacteria also gives off carbon dioxide but that isn't its main function in the levain.

In summary, your sourdough starter is a goopy utopia where wild yeast and bacteria live harmoniously. It all translates into fantastic flavor and rise for your homemade bread. If you want to geek out, take a few minutes and read this article that discusses the science in more detail.

UPDATE: The terms "sourdough starter", "mother", "seed", and "levain" are tossed around and I thought it was worth clarifying my understanding of them.

  • Mother/Seed/Sourdough Starter - These are all the same to me. This is the food pet that you feed and maintain indefinitely.
  • Levain - At a high level, levain is a portion of the starter that is destined for the bread dough. For example, some people maintain their mother/seed/sourdough starter with 100% all-purpose flour, but then a day or two before mixing their bread, they fork off some of the starter and feed it with 50% whole wheat (for example). This 50% whole wheat mixture is then used as the leaven in the bread dough.
  • Confusion - There are more complicated explanations available on the Interwebs (aren't there always). For my purposes, I'm keeping it simple.


Embrace measuring in "grams" since it's the most accurate way to approach sourdough starter maintenance and bread baking. And if you don't own a scale it's time to get on that. I have used the OXO model for several years and really like it.


A "100% hydration sourdough starter" means the levain is 1 part water and 1 part flour. In other words, for every gram of flour there's a corresponding gram of water, hence 100% of the flour is hydrated. This is the easiest starter to maintain since most recipes are written with a 1:1 ratio in mind. That being said, increasing or decreasing the hydration of your levain can alter the pH which ultimately changes the flavor profile or sourness. I haven't gone down that path but if you want to experiment there's some more info on the subject here.

Feeding and Stirring

UPDATE: I now only stir during the feeding. A sourdough starter is full of living organisms (bacteria and wild yeast) that feed off of the fresh flour and sugars in the mixture. Those organisms need to be fed regularly or they will run out of food and die. Sad. Also, yeast doesn't ambitiously travel around the bowl looking for food - it's kind of lazy. Stirring the flour mixture from time to time helps expose the organisms to fresh eats. I cover the specifics of feeding under "Instructions".

Don't get discouraged by the maintenance and feeding schedule. Once your starter is mature (usually 7-14 days) you can adjust the feedings to fit your life and/or baking habits, or just throw the starter in the fridge and feed it every week or so.


I don't recommend storing a sourdough starter in a hot location, especially in the beginning when you're trying to establish the colonies. High temperatures can encourage "bad bacteria" to grow which overrun the good bacteria, hence ruining the starter. My original levain, "Moomin I", met a quick end because I thought the hottest corner of the kitchen was a brilliant location and would help it grow faster. Not so much. And my friends, you will know if the sourdough starter has gone south. No amount of plastic bags could contain the stench of "Moomin I" when I took it out to the trash. A range of 70-75 degrees seems to be a good temperature.

Once the levain is mature - bubbling, doubling, and falling predictably - then you're free to put it in the fridge with a loose cover (already mentioned above). The cold temperature "retards" or slows the fermentation which helps spread out the feedings.

Covering Your Sourdough Starter

My preference is to simply lay a dish towel over the bowl - sometimes it's just a couple of paper towels. This prevents anything from falling in while allowing for plenty of circulation. When storing in the refrigerator, I cover the container with plastic and then punch a few holes with a paring knife. UPDATE: I did an experiment and am no longer convinced that completely covering a starter is bad (i.e. limiting the air circulation). That being said, the most popular storage method amongst the IG bread nerd community is partially covered. I'm sticking with partially covered.

Well Behaved

After feeding my levain, I can accurately estimate when it's going to be ready for baking give or take 30 minutes. I'm not a special snowflake, this is just how a mature or established sourdough starter behaves. It rises and falls in a consistent pattern which makes planning your baking schedule a snap. When you feed your starter and begin to see predictable behavior, you're on the right track.


For the first 1-7 days, a sourdough starter will go through some weird odor stages as the various bacteria get settled. This is totally normal as long as the smell isn't foul. Like I mentioned above, you'll know when things have gone bad. Once the levain is established, the scent will transition from a sweet smell after feeding to a slightly more sour smell as the starter ripens and peaks.

Is it ready?

Gently drop a spoonful of starter into a cup of water. If the glob floats, then that means it's hopped up on carbon dioxide and ready for baking. No fancy advice here, just make sure it floats. You probably won't need to do this once you get to know your starter.

Multiple Sourdough Starters

UPDATED: I maintain two 100% hydration levains. Moomin is 50% wheat Sonora plus 50% all-purpose flour and goes into my country loaf. NYoomin is 100% 50% rye plus 50% all-purpose flour. Each levain imparts its own unique flavor in the sourdough bread, the rye being more earthy while the Sonora is sweeter.


I've seen pineapple juice and various other ingredients suggested as growth aids, but in my humble opinion you only need filtered water and flour to create a starter. I think the issues people run into include the following:

  • Water Impurities - The wild yeast can be sensitive to impurities and chlorine (especially when trying to get established) so it's best to use filtered water for the levain. This seems to be a consistent piece of advice out on the Interwebs. I use the same water that we drink from our PUR filter/jug.
  • Feeding - Feeding the sourdough starter once a day is fine for the first 7-14 days when you're trying to establish the colonies of good bacteria and wild yeast. That being said, if you feed the starter too much, the bacteria and wild yeast won't have enough time to multiply and set up shop. If you feed it too little, your micro friends will run out of food. Once the levain is established the starter is heartier and there's more flexibility.
  • Flour type - Wheat flours can be finicky so if you're having trouble I recommend using only all-purpose to get a feel for the process.
  • Environmental Conditions - If it's very cold in your house, the levain may take longer to get going and it can feel like things aren't progressing. Stick with it and perhaps even skip a feeding day here and there. The colder it is the more lethargic the organisms will be. If it's too hot, your starter may be overrun by "bad bacteria" (mentioned above). If that happens and the mixture smells foul, toss it and begin again.
  • Patience - New sourdough starters are a tease. They often bubble up a few days into the process, but then they start smelling a little funny and the bubble activity becomes inconsistent to nonexistent. That's ok. If you go a couple of weeks and the starter isn't rising and falling on schedule then you may have an issue with one of the above factors.


  • OXO Scale - Measure all the things. I've been using this scale for many years and it has done a great job.
  • Thermapen - An essential kitchen tool for quick breads, sourdough, meat, and more. I bought a second Thermapen for the Airstream since it qualifies as one of my "capsule kitchen" tools. It's fast, accurate, and easy to clean. Bonus that it doubles as a handy cake tester.


  • 700g filtered water
  • 700g all-purpose flour (or 50/50 blend of all-purpose and whole wheat)

Instructions - A Starter is Born (usually matures after 7-14 days give or take)

  • Day 1 - Thoroughly mix 100g filtered room temperature water with 100g flour in a bowl at least twice the size of the mixture. Loosely cover with a dishtowel or similar and set in a warm (but not hot) spot.
  • Day 2 - This will be your first feeding. Try to feed the starter at roughly the same time each day.
    • Discard all but 100g of the starter (about half of the original 200g).
    • To the bowl, add 100g of filtered room temperature water and 100g of flour to the bowl, stir, and loosely cover.
    • Stir the starter from time to time if your schedule allows as this helps expose the wild yeast and bacteria to fresh food.
  • Day 3 - Repeat Day 2 steps.
  • Day 4 - Repeat Day 2 steps.
  • Day 5 - Repeat Day 2 steps.
  • Day 6 - Repeat Day 2 steps.

NOTE: At this point you should notice that the levain has cycled through a variety of odors but is starting to stabilize and has a familiar smell. There should also be some bubbling activity depending on the ambient temperature/environment. The goal is for the starter to bubble, double, and then fall predictably. It's not unusual or an issue if your starter isn't ready by day 7 so just keep with it. If after 2 weeks the starter still isn't rising, there may be other factors at play (see "Tricks" above).

Maintaining an Established Starter

Feeding Schedule

Once a starter is established, I feed it once twice a day at a lower inoculation than is called for while building a new sourdough starter. When building a new starter, the ratio of fresh flour and starter is 1:1 (100 grams fresh flour and 100 grams of starter) which puts the inoculation at 100%. Here is the maintenance feeding schedule that I generally use:

  • 12:00 P.M. - Combine 25 grams of ripe starter with 50 grams of fresh flour (Sonora and all-purpose blend) and about 40 grams of filtered room-temperature (73-75 degrees) water. This is a 50% inoculation or 1:2 ratio of ripe starter and fresh flour.
  • 12:00 A.M. - Combine 20 grams of ripe starter with 60 grams of fresh flour (Sonora and all-purpose blend) and about 50 grams of filtered room-temperature (73-75 degrees) water. This is roughly a 30% inoculation or 1:3 ratio of ripe starter and fresh flour.

Do I miss a feeding here and there? Of course. Just keep in mind that the microbial utopia can loose its balance in a neglected food pet which leads to off flavors as well as bread that doesn't rise as forcefully. Speaking from experience. It's very important to be familiar with the "normal" smells and behavior of your starter so that you know if something is off. For less frequent baking, see "Refrigeration vs. Room Temperature" below.

Refrigeration vs. Room Temperature

I store my starter at room temperature when not traveling and feed it once twice a day as mentioned above. If you only bake once every couple of weeks, you might want to consider storing your starter in the refrigerator. For refrigeration:

  • Combine 25 grams of ripe starter, 100 grams of flour, and 80 grams of filtered water. Mix thoroughly.
  • Leave mixture out at room temperature for about 30 minutes.
  • Cover with plastic, poke a few small holes, and refrigerate.

The starter can take a cold nap for up to a week. Truth is, I've left mine in the fridge for two weeks with an even lower inoculation, but I usually freeze or dry some starter as a backup in those circumstances.

When ready to bake, take the starter out a couple of days ahead of time and resume a normal feeding schedule to wake it up. I prefer to feed the starter four times between refrigeration and baking.

Data Points

I like to periodically measure the temperature of my sourdough starter since I store it on the counter without any special setup. This gives me a better understanding of how it behaves at different ambient temperatures.

Baking with a Sourdough Starter

For baking, I generally use my levain about 1-3 hours after it reaches the "floating stage". I'll expand upon this in a sourdough recipe post.

UPDATE: Continued Reading

Dave Miller's Sourdough Starter Maintenance

Loaf 13

Related Posts