Sourdough Primer and Notes

This is what an active starter should look like.

This is what an active starter should look like.

I’m getting ready to teach a sourdough class at the 2016 National DOG in Ohio. I thought I would share my notes and the links where you can find additional info. So, here you go – enjoy.

Tips for Manipulating Sourdough

The term ‘sourdough’ refers to the process of souring or fermenting bread dough, not necessarily the flavor. Whether you prefer a tangy flavor to your sourdough bread or a more mild taste, sourdough starter and dough can be manipulated to produce a bread that tastes great to you and your family.


There are two main acids produced in a sourdough culture: lactic acid and acetic acid. Acetic acid, or vinegar, is the acid that gives sourdough much of its tang. Giving acetic acid-producing organisms optimal conditions to thrive and multiply will yield a more tangy finished product with more tang.

Adjust the starter:

  • Maintain your starter at a lower hydration level. Lactic acid-producing organisms seem to thrive in a wet environment whereas acetic acid is produced more abundantly in a drier environment.
  • Use whole-grain flours, which the acid-producing bacteria love.
  • Keep the hooch, or brown liquid layer that forms on a hungry sourdough starter. Retaining hooch can add acidity to sourdough.


Adjust the bread dough: 

While it may take a little trial and error, attempt to achieve a longer, slower rise by

  • Finding a cooler spotfor rising the dough.
  • Punching down (degassing) the dough at least once, if not twice, before the final shaping of the loaf.
  • Performing the final rise for at least four hours or overnight in the refrigerator. Take the dough out of the refrigerator and let it sit at room temperature for about 30-60 minutes before baking. Although many experts recommend that the last rise be a quick one done in a warmer environment, you will have better “oven-spring” by putting a cooler loaf into a hot oven.



These adjustments will achieve the opposite effect from those mentioned above, for a milder flavor in the finished product.

Adjust the starter: 

  • Feed your starter regularly to minimize the alcohol content and reduce the overall acidity of the sourdough.

Adjust the bread dough:

  • Use more starter in the dough. A larger percentage of sourdough starter in the dough allows it to both rise in a cooler location and have a shorter rising time.  Both of these conditions aid in taming the sourness in sourdough by lowering acetic acid production.
  • The amount of starter may need to be adjusted by season: more starter in the winter and less in summer.
  • Add baking soda. Baking soda is an alkaline substance. Adding it to sourdough neutralizes some of the acidity and gives the dough a little extra leavening boost.

Each sourdough starter is unique, so keep adjusting until you produce a bread that is ideally suited to your taste.

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Location & Wild Yeast

The different microorganisms available from location to location will affect the composition of your starter to an extent. While there are tons of different beasties that can each contribute different characteristics, they aren’t as location dependent as you might think. For instance, lactobacillus sanfranciscensis, the lactic acid producing bacteria responsible for San Francisco sourdough is found all over the world. What matters most is actually the conditions that you grow your culture in. Sort of “location in your house” vs “location in the world”. The differences in regional sourdough breads are more likely caused by regional differences in how the dough is handled. For instance, in many European baking traditions, a small portion of starter will be used in bread that will be proofed and baked in the same day. In San Francisco, many bakeries first make a sour sponge, then incorporate a large portion of that into the final dough which will get both a long bulk fermentation, and a long final proof, sometimes totaling over 70 hours!

Some tips to control the character of your culture are: lactobacteria prefer warmer (as in room temperature) environments, whereas the organisms that produce acetic acid grow best in a cooler environment. Lactic acid is also produced more rapidly in a wet culture, and acetic acid in a dry culture. You can further manipulate these by adjusting your feeding intervals and the carbohydrates used to feed.

Temp, Water/Flour Ratio, Salt & Oil, Flavor

I’ve frequently baked (about once to twice a week) with sourdough for 4 years now. I’m not a professional. The only thing I can take a bit of pride in is that a professional baker who tested a loaf of my sourdough bread told me that it’s “fantastic, considering the little possibilities available to control the conditions the sourdough and loaf are exposed to at home”. So while far from perfect, I’d consider my sourdough breads and knowledge pretty good.

Most of what I’m writing now was first read on the internet somewhere and confirmed through testing it with my own sourdough culture (I’m still using the same one I started out with).

Apart from the flour you use, there are several factors that affect the taste of the resulting bread:


This has, in my experience, the biggest impact on the taste. The following rules apply:

  • Anything over 104°F (40°C) is deadly to the microbes in your sourdough.
  • Lower temperature: More acetic acid, less lactic acid, yeasts develop more slowly.
  • Higher temperature: More lactic acid, less acetic acid, yeasts develop more quickly.
  • Lactic acid bacteria prefer temperatures at around 86° – 95°F (30-35°C)
  • Yeasts like temperatures around 77° (25°C) best

Note: Your sourdough can be 30° – 35° warmer than the environment due to microbial activity. That can be important to keep in mind.

Water/flour ratio

Most of the time, people use a ratio of 1:1 water/flour for the sourdough and that will give you good results, but you can play around with that ratio to change the taste to your liking:

  • Lower water content causes more acetic acid production and less developed yeasts
  • Higher water content will make it easier for the yeasts to grow and increase the lactic acid content
  • I’ve found that having more than 1.5 times the amount of water compared to the flour will hardly have any effect on the dough anymore and I’d recommend stirring the dough every couple of hours with that much water.
  • On single staged sourdough, using less than 0.75 times the water compared to the flour is also not a good idea and you will probably be required to add yeast in the bread dough.

Salt and oil

Adding these, especially salt, to the sourdough already will have a considerable impact on the sourdough taste. A sourdough made with salt in it will taste quite different from one without it. I’m not quite sure about why this is, but it may have something to do with the yeasts growing more slowly (more information below).

  • Both salt and oil will slow down the growth of the yeasts, but don’t have much of an effect on the lactic acid bacteria.
  • Adding oil mainly affects the mechanical properties of the dough (it will be softer and more ductile). It also helps with the structure of the bread (the air bubbles in the bread will be smaller and more uniformly distributed), especially in the presence of an emulsifier (lard is both fat and an emulsifier, so it works well in this regard). For this reason, it doesn’t make much sense to add it to the sourdough already.

Of course, if the fat isn’t tasteless, it will also add to the taste of the bread (I love using natural olive oil in my wheat breads).

Flavor of the bread

Sourdough actually has some pretty complicated chemistry. I’m not a chemist, however, here are some effects that I do know:

  • Lactic acid will give your bread a mild, sour taste. This works very well for wheat breads.
  • Acetic acid gives you a stronger, more sour taste (very noticeable while eating). This works great for rye breads
  • The amount of yeast in your sourdough also has a big impact on the smell and taste of the bread. Yeast is beneficial to the bread not only for its leavening properties. Apart from CO2, it also produces ethanol, which will esterify the lactic acid to ethyl lactate over time, which in turn has a strong flavor. Ester is an organic compound made by replacing the hydrogen of an acid by an alkyl or other organic group. Many naturally occurring fats and essential oils are esters of fatty acids.


Here are a couple of recipes you might want to start with. The first is a traditional starter that will last for as long as you keep it healthy. The 2nd one is a cowboy starter. Purists will argue that it is not a real or genuine starter since it uses commercial yeast. But it is a good starter to practice with using in many recipes. It is hardy but only lasts about a week before you have to make a new batch.

Basic Wild Yeast Starter

  1. Combine¾ cup flour and ½ cup warm water in a glass or plastic container. Make sure the container can hold about 2 quarts, to avoid overflow.
  2. Stirvigorously to incorporate air; cover with a breathable lid.
  3. Leavein a warm place, 70-85°F, for 12-24 hoursFeeding every 12 hours will increase the rate at which your sourdough starter is multiplying its organisms; feeding every 24 hours will take a bit longer, but may be more sustainable depending on your time commitment.
  4. At the 12 or 24 hour mark you may begin to see some bubbles, indicating that organisms are present. Repeat the feedingwith ½ cup warm water and ¾ cup flour.
  5. Stir vigorouslycover, andwait another 12-24 hours.
  6. Repeat feedingsevery 12-24 hours by removing half of the starter before every feeding and discarding it. Feed with ½ cup warm water and ¾ cup flour.
  7. After about 5-7 daysthe sourdough starter should have enough yeasts and bacteria to be used for baking.




Cowboy Starter

I had the privilege of attending Kent Rollins Chuck Wagon Boot Camp. During the week we used sourdough several times. This was a quick starter in that yeast, potato and sugar. This is the type of starter that you would see on the 19th century cattle drives. Old Cookie needed a quick starter that could be ready within 12 hours and didn’t need the constant care and feeding that tradition starters require. Kent said in his book, “A taste of Cowboy”,  “Traditional sourdoughs are like needy horses. You have to feed them, read them a bedtime story every night, and feed them again.” I highly recommend Kent’s book if you are at all interested in chuck wagon cooking. I got my copy from Amazon.


Here it is:


4 cups warm water

1-1/4 tsp rapid-rise yeast

5 TBLS sugar

4 cups all-purpose flour

1 russet potato, peeled and quartered



  1. Add the warm water to a crock or glass jar that hold at least 1 gallon. This will prevent the starter from flowing over when it rises from the activation process. Do not use a metal container as it will react in a way that will not promote fermentation.
  2. Whisk in yeast and sugar and let sit for a minute. You will see some bubbling activity. This is good.
  3. Slowly whisk in flour. Drop the quartered potato into the bottom of the crock. Cover with a tea towel and let sit in a warm spot for at least 12 hours, stirring halfway through. You can let the starter sit longer for a more sour flavor.
  4. Before using the starter in a recipe, whisk it briskly until smooth.



The consistency of this particular recipe will be very liquid rather than thick like a light pancake batter as you might find in some traditional starters .


After using 3 cups of the starter, whisk 1-1/2 cups warm water, 1-1/2 cups all-purpose flour and 1-1/2 TBLS sugar. The starter is ready to use again or you can let it sit for 6 to 12 hours. This will result in a slightly more tart taste.


Do not refrigerate this recipe.


You can keep using the starter until the potato starts to deteriorate. When this happens, start a new batch.



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