What does a 100% Hydration Sourdough Starter mean?

This post is an ultimate guide to what an 100% hydration sourdough starter is, its impact on flavor, fermentation, and activity.

Learn how to easily maintain and care for this starter to create consistent, vigorous activity for great sourdough bread making.

Get all the tips for making your bread more sour or less sour as well as information on different types of sourdough starters.

Hydration in Baker’s Percentages

Baker’s percentages help bakers know the percent of each ingredient in a dough formula.

Hydration is a very important percentage. Hydration refers to the ratio of liquid in a recipe compared to the total amount of flour in the recipe.

Here’s the basic formula: weight of water* in grams ÷ weight of flour in grams = percentage in decimal points x 100 = percentage number %

For the best sourdough baker’s formula, the parts of the starter used should be divided and added into the total water before dividing to find the hydration level of sourdough.

I have a template for Baker’s percentages included in my Sourdough Time Planning and Baker’s Journal here. Also see the calculator below for calculating the hydration in a sourdough bread recipe.

The Bacterial Activity in Sourdough Fermentation

As sourdough starters develop, they produce byproducts by using the flour as fuel and the water as a means of moving around in the mixture.

The byproducts from sourdough fermentation are carbon dioxide gas, lactic acid bacteria, and acetic acid bacteria.

The more acids that are produced, the more sour the flavor of the sourdough bread will be.

A higher water amount creates an environment that favors more acid development and is, therefore, more sour.

Different hydration levels in starter types impact the fermentation and good bacterial activity that develops.

Less water content produces less acids overall but a higher amount of acetic acid resulting in a more mild flavor. Whereas, an equal amount of water (in weight) produces more acids overall and a higher concentration of lactic acid bacteria, which is the best way to create more sour flavor.

What is a 100% Hydration Sourdough Starter?

The type of starter that most sourdough beginners learn to use is a 100% hydration or liquid starter.

The 100% refers to the feeding ratio of water to flour that is used to feed the small portion of sourdough. Equal amounts of flour and water are used.

For example, the amount I recommend feeding a tablespoon portion of sourdough starter for one loaf of bread is 60 grams of water and 60 grams of flour. See this post to learn about how to care for a starter.

That calculation is 60 g water ÷ 60 g flour = 1 x 100 = 100% hydration

The higher hydration creates more acids. The wild yeast and lactic acid bacteria reproduce and move around the mixture more easily during the fermentation process.

Use the starter calculator on this post to create a larger batch of sourdough starter for a big bake.

Can you make a Sourdough Starter?

Yes! You can make a sourdough starter from scratch.

You can get my free guide to make your own sourdough starter here: How to Make a Sourdough Starter Free Guide

How does a 100% Hydration Sourdough Starter impact flavor and fermentation?

This type of starter easily mixes in with liquids when making bread dough, is easy to mix and maintain, and is one of the most common used by sourdough bakers. Since it is so common, it is sometimes known as “regular starter” or “regular sourdough starter”

When fed with white flour, it produces homogenous fermentation which means the results are consistent and predictable.

The flavor created once it’s active and added to bread is slightly sour and there’s an aroma of ripe fruit. The bread made with this starter will ferment quickly compared to sourdough breads made with starters with a lower hydration level. The finished product will also have a more sour flavor.

It is very beginner friendly and it only takes a few minutes to care for this type of starter since it mixes so easily during the refreshing process.

Active stage of a 100% Hydration Sourdough Starter

When a 100% hydration starter becomes active, it will be at least double in volume with large bubbles and a ripe fruit aroma.

You can use a rubber band to mark the volume level in the jar or container after feeding to have a visual gauge of when it has doubled.

The look and texture of the starter will change over the course of fermentation from a dull look and rough texture to shiny and smooth.

The top of the starter should look relaxed and beginning to create a valley or dip in the surface. If the top of the starter is still rising like a dome, it still needs time to reach its peak of activity.

Learn more about this stage in this post:

How to Know When your Sourdough Starter is Ready (8 signs)

Maintaining a Healthy 100% Hydration Sourdough Starter

Your sourdough starter likes consistent, regular care. The more consistent your rhythm of care and use, the more consistent your sourdough starter will perform.

The good news is that you don’t have to refresh your starter every day to have a consistent, healthy starter.

When your sourdough starter is not in use, keep it in your fridge for up to a week. Even if you don’t plan to bake sourdough every week, plan to refresh your starter every week.

How to have a Low-Maintenance, High Performance Sourdough Starter

For the best activity, take the starter out 1-2 days before you plan to make your dough to perform two consecutive refreshes.

Refresh it by moving a tablespoon amount to a new container and feed it with equal parts of flour and water by weight. Let the first round of refreshed starter become active.

Once its active, repeat the process by refreshing a second time. Two consecutive starter refreshes at room temperature will produce more vigorous activity for your recipe.

If you only do one refreshing after the starter has been in the fridge, it will still perform well as long as you use my recommended ratio of 1 part sourdough starter to 3 parts water and 3 parts white flour.

This is referred to as a 1:3:3 ratio. It is composed of about 10-20% older or previous batch of sourdough starter to 80-90% fresh flour and water.

The smaller proportion of sourdough stater to the higher proportion of flour and water creates stronger activity, especially if you plan to use the fridge to maintain your starter rather than daily (or a more frequent feeding schedule) refreshing.

Key tools for Starter Care

Kitchen Scale (budget-friendly kitchen scale, nicer glass top LED screen kitchen scale)
Wide-mouth pint-size glass jars (at least 2-3, walmart has the best price typically)
Scottish spurtle or Danish dough whisk, you can use a spoon but these tools are dedicated and created for easy mixing
Reusable mason jar lids, great replacement for the metal canning lids (plastic lids, cute wood/silicon lid version)
2-quart Cambro container for making large batches of starter

Best tips to increase sour flavor in sourdough recipes

Use an active starter with 100% hydration.
Experiment with different flours to create more sour flavors in the dough and in the starter (see section below for more info.). Rye flour, for instance, will create more sour flavor. Try making my Sourdough Country Bread and use rye flour for the whole wheat flour portion.
A wetter dough recipe will create a more sour flavor. Typical hydration levels that are beginner friendly and create more sour flavors are 65-75%. You can use a higher hydration level of dough, but it may be more difficult to work with. Use the calculator below to see what your dough’s hydration level is!
A warm room temperature for fermentation creates more sour flavors.
Longer fermentation will also build up more sour flavors, but you must pay attention to the dough. If a dough ferments too long, you will be left with stringy dough that falls apart and lacks good structure. I recommend using 9 hours in warm weather, up to 11 or 12 in cooler weather to create more sour flavor during the bulk fermentation. Make sure to read this post on bulk fermentation to know what to look for.

Recipes best for creating a more sour sourdough bread

Calculating your dough’s hydration

Use this calculator to see what your total hydration percentage is when using a 100% hydration starter, including the adjusted percentage for common ingredients that impact hydration:

How to create a more mild (less sour) flavor with 100% hydration starter

I often use a 100% hydration starter to create breads with a mild or sweet flavor.

When a 100% hydration starter is added to a lower hydration dough with enriching ingredients, it will come out mild and sweet with just a subtle undertone of tang that creates a complex flavor profile.

Another strategy to make your sourdough recipes tasted more mild is to use cold fermentation and proofing. The cold temperature changes the way that the dough ferments and creates more acetic acid that tastes less sour than using room temperature fermentation.

Some of the mild or sweet recipes I use this type of starter in are listed below:

Different starter types

The two most common types of sourdough starter are 100% hydration and a stiff starter.

If you have experience with making preferments with commercial yeast, a 100% hydration sourdough starter is similar to a poolish which is made with commercial yeast and a stiff sourdough starter is similar to a biga made with commercial yeast.

See this post for a comparison of how these two common sourdough starters behave in the same recipe!

You can also use different varieties of flour to create a unique flavor profile and fermentation activity as described in one of the sections below.

Stiff Sourdough Starter

This type of starter has many advantages, but is not one I’d recommend jumping into if you are new to sourdough baking.*

Here are some advantages of using a stiff sourdough starter:

Your bread will be less sour (an advantage if that’s your preference).
The rise of enriched breads like brioche or other sweet breads is much higher and has more volume than when using a 100% hydration starter.
The starter stays in its active window longer than a 100% hydration starter.
The interior crumb and texture of enriched breads is more even and cake-like.

*My notes: Beginner sourdough bakers should have a firm grasp on how to maintain a 100% hydration starter and have an established care routine. It is also my opinion, that beginner sourdough bakers work to develop a confidence and consistent proficiency with a favorite sourdough bread recipe in order to lay the foundation for lifelong sourdough baking.

Although this starter has advantages, a few reasons why a stiff starter isn’t a great recommendation for new sourdough bakers is the variability and the time needed to maintain it. A stiff sourdough starter takes more time to create because the thicker starter consistency takes longer to mix together.

Stiff starters are not created equally. Recipes will use different hydration percentages, which can be a challenge for new sourdough bakers.

Different types of flour in your sourdough starter

I’m often asked about using different types of flour in sourdough starters.

The type of flour used to feed or maintain a sourdough starter will have a big impact on starter flavor, activity, and rate of fermentation.

Typical timing for white flour starters is 6 to 12 hours from feeding to its active stage.

Rye flour will ferment the most quickly. A rye starter will take 2 to 4 hours from feeding to active because of the high level of enzymes that encourage fermentation, which is why I recommend using rye flour if you are making a sourdough starter from scratch.

Rye flour absorbs a lot of water so often the hydration needs to be increased to saturate the flour.

Whole wheat flour will ferment more quickly than white flour. It typically takes 4 to 6 hours to become active from the time of feeding to the time it is active.

When using different whole grain flours, it adds a variability to the starter and creates heterogenous fermentation due to the new enzyme activity and higher concentrations of microorganisms on the bran of the flour.

I recommend keeping a white starter which creates consistent homogenous fermentation. And using a portion of the white sourdough starter to create different types of starter with whole grain flour in a separate container.

When using whole wheat flour varieties, use organic since the bran contained in whole wheat flour contains any residue from chemical treatments.

Share this info with a friend

Your sourdough baking friends will love learning how these starters are different. Make sure to share this post!

Let me know if you plan to make a bread with a stiff sourdough starter! Send me a note, leave a comment, or tag me on facebook or instagram @livingbreadbaker

Need more sourdough help?

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My Intro. to Sourdough online course is comprehensive with video tutorials for each stage of the process to help new or aspiring sourdough home bakers gain a solid foundation for sourdough, the traditional way, to learn all the basics, language, techniques, and the process from start to finish to make sourdough bread.

My teaching is straight forward and makes the whole process seem simple. I have helped launch hundreds of eager sourdough bakers onto their own inspiring sourdough journeys.