Rye Sourdough Starter is - by far - the easiest sourdough to start. All you need is rye flour and water.

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It only takes about 5 days to establish a new Rye Sourdough Starter. Once established, Starter can easily be converted to a white or whole wheat flour starter: it all depends on what kind of flour you choose to use going forward.
What Does 100% Hydration Mean?
This Rye Sourdough Starter is a what is referred to in the sourdough world as a 100% hydration starter. A 100% hydration sourdough starter is a sourdough culture which is kept and fed with equal weights of water and flour. (For example, 2.25 ounces water to 2.25 ounces of flour.)
By contrast, a 166% hydration starter is fed with equal volumes of flour and water. For example, ½ cup of water (4 ounces) to ½ cup flour (2.25 ounces).
What You Need to Make Rye Sourdough Starter
★ Flour: Use any high quality, finely ground, fresh rye flour. (We use Bob's Red Mill Organic Dark Rye Flour.)
It is important to note that whole-grain rye flour has a short shelf life (three to four months) and should be stored in an airtight container in the refrigerator. It will keep in the freezer for up to six months. Rye flour with the germ removed will keep for slightly longer than whole-grain rye flour.
★ Water: When I made this starter the first time, I used plain old tap water, and everything bubbled up just fine. Nevertheless, many sourdough professionals discourage the use of tap water in favor of distilled water, as the chlorine and other chemicals found in treated water can kill the microorganisms that need to flourish to create sourdough.
I now use distilled water for all my sourdough, but I wanted to share my experience with tap water because unless your city uses an excessive amount of chlorine in your water supply, it's not a deal-breaker. (If you would rather use tap water, but want to remove at least some of the chlorine, there are a couple of ways you can dechlorinate water at home.)
Materials & Tools
- Quart-size Mason Jar (Wide mouth is best)
- Breathable Jar Covering
- Wooden Spoon
- Kitchen Scale (optional)
How to Make 100% Hydration Sourdough Starter
Points to Remember
- Never allow reactive metal to come in contact with your sourdough starter. Always use a wooden spoon to stir when you feed it. Starter should be stored in glass, plastic, or pottery containers.
- Always leave enough room in your Sourdough Jar for the Starter to triple in size. It usually only doubles, but you want to leave some wiggle room.
- Never cover your starter with an airtight lid.
Day 1
You will need: 2¼ ounces rye flour + 2¼ ounces water
Using a wooden spoon, mix the rye flour and water in a mason jar or non-reactive bowl. Cover loosely and place in a dark place at 70°F for 24 hours. (I put mine up against the counter right next to my stove.)
Your unfermented Starter will be the consistency of thick cook dough. It will loosen up over time.

Day 2
You will need: 2¼ ounces rye flour + 2¼ ounces water
Add the rye flour and water to the starter. Mix with a clean wooden spoon for 30 seconds until the flour has been incorporated. Cover loosely and place in a dark place at 70°F for 24 hours.
Day 3
You will need: 1⅛ ounces rye flour + 1⅛ ounces water
Add the rye flour and water to the starter. Mix with a clean wooden spoon for 30 seconds until the flour has been incorporated. Cover loosely and place in a dark place at 70°F for 24 hours.
Day 4
You will need: 1⅛ ounces rye flour + 1⅛ ounces water
If bubbles have started to form and the flour has begun to ferment, discard ⅔ of the mixture in the jar. Add the flour and water to the remaining ⅓ and mix for 30 seconds until the flour is well incorporated. (If the mixture has not started to ferment repeat step 3.)
Day 5
The starter should be mature by this point and is ready to use. Use the starter as needed. After use, see feeding instructions.
If you want to convert your starter to a white flour or whole wheat Starter, you may begin feeding it with all-purpose flour from this point on.

Safe Sourdough Starter Storage
NEVER leave sourdough starter in direct sunlight. (Seriously. Remember Gremlins?)
According to the sourdough pros, 70°-80° F [21° - 27° C] is the ideal temperature range at which to keep your sourdough starter.
If I am actively using my starter on a regular basis, I keep it on my kitchen counter near my stove. (I've also had good luck in the past keeping it on top of the fridge.) If I am taking a break from sourdough baking, I let my starter chill in the fridge.
If kept below 70°F [21°C], the natural yeast in the starter incubates very slowly; above 80°F [27°C], the starter will tend to ferment alcoholically, which is not desirable.
Troubleshooting: If you ever forget your starter in the back of the fridge and it looks scary when you take it out, be sure to check out our Lazy Caretaker’s Guide to Sourdough.
NEVER cover your starter with an airtight lid!
The natural fermentation process creates gas, and that gas needs to have a place to go, so you need to cover your container with something that will allow some of that gas to escape.
We have successfully used all of the following methods:
- Rubber Band and a clean cloth. Not pretty, but it works.
- Mason jar ring and a piece of clean cloth. I usually use muslin in this case.
- Pickle Pipes (or other lid designed for fermentation)
I discovered Pickle Pipes some time ago, and I LOVE LOVE LOVE them! For the money, they are (IMHO) the best solution for the job. (Just to clarify, this is NOT a sponsored post; but that is an Amazon affiliate link.)
- Pickle Pipes feature one-way airlocks that vent gas automatically so they require no burping or babysitting.
- Prevent spoilage by releasing the gas that builds up during the fermentation process.
- Some people like to call them Pickle Nipples, which is fun to say. (Try it 3 times fast... and GO!)
- They prevent oxygen and airborne contaminants from getting inside.
- They are food-safe. (e.g., BPA-free, no phthalates)
- They are Dishwasher-safe.
Stages of a Healthy Sourdough Starter
♣︎ Fed Starter – Fed Starter is active, healthy starter that has been fed within about 2 hours. By hour 2, it will be producing little bubbles on the surface.
♣︎ Active Starter – Starter is Active about 5 hours after feeding. By hour 5, you should be able to watch large bubbles actively rising through the Starter and making their way to surface.
♣︎ Ripe Starter – Starter is considered Ripe about 8 hours after feeding. The volume has doubled, and the top is just beginning to show signs of sagging under its own weight.
♣︎ Unfed Starter – Unfed Starter is healthy, vigorous Starter that has not been fed for 12 hours or more. By hour 12, it collapsed after Ripening, and is ready to be fed again or put in the fridge until next time. (Note that this is NOT neglected Starter that hasn’t been fed in days.)
♣︎ Discard – Sourdough discard is the portion of your sourdough starter that you get rid of when you do a feeding. It should be healthy and vigorous, with some small bubbling activity.
Many recipes, including most bread recipes, call for feeding your starter the night before and using it in the morning. When you do this, you are technically using Ripe or Unfed Starter, depending upon the vigor of your starter and how much time elapses between last feeding and usage.
FAQs & Expert Tips
The amount you feed your sourdough starter depends on how much of it you have to start with. You want to approximately double your starter each time you feed it. So, for example, if you have 8 ounces of Starter, you will feed it 4 ounces of water and 4 ounces of flour.
If you have more starter on hand than you anticipate using for baking, you can toss (or share!) a cup or more of Starter and then double what remains. You always want to have at least 8 ounces of Starter leftover after baking to keep the process going.
Read Sourdough Starter: Care & Feeding for tips and advice for the care and feeding of a sourdough starter, including how to maintain it, and how to revive a neglected starter.
Healthy Starter can be refrigerated for up to a week between feedings; however, most sourdough experts recommend feeding Sourdough Starter at least twice a week for best results. (Honestly, I often leave it FAR longer with no problems.)
Nope. Once your starter has been established, you can convert it to a white or whole wheat Starter by feeding it with your chosen flour.
Get a Kitchen Scale
If you don't already own a kitchen scale, now might be the time to get one - and this is coming from someone who usually measures everything by pinch and palm!

I honestly don't know how I ever lived without a good kitchen scale. Weighing the water and flour for your sourdough starter keeps the hydration consistent, which in turn gives you more consistent results in your cooking and baking. (I don't use any measuring cups when I make bread - I weigh everything!)
If you don’t have a kitchen scale, measure out ⅔ to ¾ cup of water for every cup of flour.

Easy Sourdough Recipes
You don't need a special recipe to sourdough starter! Nearly all of your favorite yeast bread recipes can be adapted to use sourdough starter, as can many quick breads.

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Rye Sourdough Starter (100% Hydration)
Equipment
- 1 wide-mouth quart jar
- 1 breathable jar covering
- 1 Wooden Spoon
- 1 Kitchen Scale optional
Ingredients
- 7 ounces rye flour divided
- 7 ounces water divided
Instructions
Day 1
- You will need: 2¼ ounces rye flour + 2¼ ounces waterUsing a wooden spoon, mix the rye flour and water in a mason jar or non-reactive bowl. Cover loosely and place in a dark place at 70°F for 24 hours. (I put mine up against the counter right next to my stove.)Your unfermented Starter will be the consistency of thick cook dough. It will loosen up over time.
Day 2
- You will need: 2¼ ounces rye flour + 2¼ ounces waterAdd the rye flour and water to the starter. Mix with a clean wooden spoon for 30 seconds until the flour has been incorporated. Cover loosely and place in a dark place at 70°F for 24 hours.
Day 3
- You will need: 1⅛ ounces rye flour + 1⅛ ounces waterAdd the rye flour and water to the starter. Mix with a clean wooden spoon for 30 seconds until the flour has been incorporated. Cover loosely and place in a dark place at 70°F for 24 hours.
Day 4
- You will need: 1⅛ ounces rye flour + 1⅛ ounces waterIf bubbles have started to form and the flour has begun to ferment, discard ⅔ of the mixture in the jar. Add the flour and water to the remaining ⅓ and mix for 30 seconds until the flour is well incorporated. (If the mixture has not started to ferment repeat step 3.)
Day 5
- The starter should be mature by this point and is ready to use. Use the starter as needed. After use, see feeding instructions.
- If you want to convert your starter to a white flour or whole wheat Starter, you may begin feeding it with all-purpose flour from this point on.
Feeding Sourdough Starter
- The amount you feed your sourdough starter depends on how much of it you have to start with. You want to approximately double your starter each time you feed it. For example, if you have 8 ounces of Starter, you will feed it 4 ounces of water and 4 ounces of flour.
- If you have more starter on hand than you anticipate using for baking, you can toss (or share!) a cup or more of Starter and then double what remains. You always want to have at least 8 ounces of Starter leftover after baking to keep the process going.
- Healthy Starter can be refrigerated for up to a week between feedings; however, most sourdough experts recommend feeding Sourdough Starter at least twice a week for best results. (Honestly, I often leave it FAR longer with no problems.)
- Read Sourdough Starter: Care & Feeding for tips and advice for the care and feeding of a sourdough starter, including how to maintain it, and how to revive a neglected starter.
Notes
Nutrition
This website provides approximate nutrition information for convenience and as a courtesy only. You are solely responsible for ensuring that any nutritional information provided is accurate, complete, and useful.
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UPDATED: Originally published September 14, 2015
Michael Borza says
Using the same Bob's Red Mill rye flour as your picture shows and expiration is Feb 2025.
Well already on day 3 my starter was roughly double in size and with bubbles, so I applied what you said should happen in day 4: that is I discarded 2/3 of it and I fed it with 1and1/8 rye and 1and1/8 water. Next day no bubbles anymore and almost no rising. Any clue please?
Renée B. says
Is it possible the environment is a little chilly? The temperature of your kitchen can dramatically affect the speed of the sourdough process. Give it an extra day and see what happens. If that doesn't help, go back to step 3, and allow it 2 days between steps instead of one. Also, try using distilled water (if you're not already): some cities use too much chlorine in their water supply.
Starting a new sourdough starter is by no means a cut-and-dry process: type of flour, quality of water, outside temperature, and vessel all affect the outcome.
Hope this helps.
Becky says
Hi I started my Rye Starter & put it my microwave leaving the door cracked open which allows the light to stay on, & I kept the jar lid just barely cocked to the side..day 2, I checked on it & it had white fuzzy “hair” growing on top. I chucked it. What am I doing wrong? I’m getting SO discouraged...
Renée says
That definitely sounds like mold. You did the right thing: in my experience, there is no coming back from mold. The most likely culprit is either the jar you are growing the starter in or the flour you are using.
It is imperative that the vessel you grow you starter in is sterile. Not that it just "looks" clean, but that it is sterile. You should move starter to a new, sterile jar every couple times you feed it, too.
It is also important that the flour you use is fresh. Rye flour has a very short shelf life, and last only 4-6 months unrefrigerated; and then only that long if it is properly stored in an air-tight container.
Also, check the temperature of the environment you have set up: it shouldn't be much higher than 70°F | 21°C.
Hope this helps!
Lisa says
Thanks, Renee! I'm on Day 2 and so far so good. I'll let you know how it goes.
Lisa says
What about the starter having to double in size, noting the rise and fall of the starter? What about the float test to determine if your starter is ready to bake with? How do you know for sure that the starter is mature? This is seriously my tenth attempt at creating a sourdough starter and I'm praying that your recipe is the one!
Renée says
I hope so too, Lisa.
I cannot imagine what is happening that would make ten sourdough starters fail. I'm sure you've already checked these things, but just in case, here are a few troubleshooting thoughts: First, rye flour has an expiration date, after which it can go bad on the shelf quickly. Be sure that the rye flour you are using to create your starter is fresh. Also, be sure the water you are using is free of chlorine. If you live in a town that chlorinates their water, it is imperative that you allow the water to set out for a day or two so the chlorine can dissipate before you use it to feed your starter.
Those are really the only two things I can think of that could be impeding your sourdough's progress.
As for when it is ready: I know some people do float tests and watch their starter rise and fall like a baby taking its first steps, and that works for them. There is nothing wrong with any of it. However, I've always done sourdough rather intuitively, as the instructions here reflect. A starter is mature five or six days after it begins; when it is vigorous and bubbly and "smells like sourdough." Depending on the time of year, the weather, the vessel, and the temperature on your kitchen counter, it can take up to eight days for a starter to really get going, which is also fine. After the initial build-up, and with regular feeding, a healthy starter will be ready to bake with in 8-12 hours after feeding. It's really as simple as that.
When you get that starter going, be sure to check out our Easy Sourdough Bread recipe. It's a very forgiving, total beginner step-by-step recipe: nothing fancy, but you'll end up with a delicious loaf of bread, and understand the sourdough process a bit more without a lot of frustration.
Colleen says
I am confused for weekly feeding amounts.
It says follow day 4 which is 1 1/8 each water and flour but it also says 3oz each.
Made Soft pretzels for thanksgiving they were delicious with everything bagel seasoning.
Renée ♥ says
Thanks for the question, Colleen. I've updated the recipe card: hopefully it is more clear now. Basically, on Day 4, you are still building your starter, so feed it with 1 1/8 ounces water and flour. The 3oz refers to the regular weekly feeding, after your starter has been established.
Serena Jane says
Ok thank you! It was bubbly today but still a bit thick so did add some more and will see how it is tomorrow.
It does smell really sttrong aswell which I'm guessing is normal especially since I'm milling my own flour?
Renée ♥ says
OK... you're milling your own flour: that may affect the water absorption, which would impact the density of the mix. Just a theory.
And yes, your starter should have a distinct, sourdoughy scent; however, it should not be off-putting. From what I've read, hand-milled flours can introduce undesirable wild yeasts that can ruin your sourdough (as opposed to the "desirable" wild yeast you are looking for). This isn't to say you shouldn't use it: just that doing so may take a bit more investigation into the process. Perhaps you could Search for more advice on "home-milled flour sourdough starter" and see what helps. I wish I had more advice to offer; unfortunately, while I've milled my own flour on occasion, I have no experience with it in regard to sourdough maintenance. Best of luck, Serena