9 Sourdough Misconceptions & Myths

The following are 9 common misconceptions and myths regarding traditional sourdoughs for bread baking. That is, sourdoughs maintained by regular feedings or refreshments (technically referred to as backslopping).

1. San Francisco sourdough can only be made in San Francisco (USA)

False. The bacteria that was formerly associated with only San Francisco sourdough, called Lactobacillus sanfranciscensis, has been identified in other regions of the world. Regardless of location, it’s possible to produce San Francisco-style sourdough by treating the starter and dough in certain ways. For example, you may retard (chill) the dough overnight to sharpen its tang and induce crust blisters.

San Francisco-style sourdough

Blistered, amber-brown crust, with a mouth-puckering tang
(Photo courtesy of David)


2. Metal reacts with sourdough and contact between them should be avoided

Yes and no. Sourdough is naturally acidic and long exposure to specific metals, such as copper and aluminum, may damage the material. Thus, it’s advised to keep starters in glass jars or plastic containers. However, brief contact with metals, for instance, mixing the starter with a stainless steel utensil, will not cause detrimental effects to the metal or sourdough.

Futurama Bender

I wonder, if Bender could eat sourdough, would he have digestive problems?
(Photo courtesy of Bman2006)


3. Starters are created by “capturing” wild yeast and bacteria from the air

Wrong. Unsterilized flour contains enough microorganisms to populate a new starter, but it could be argued that the yeast and bacteria were originally airborne. In a study by the American Association of Cereal Chemists in 1978, bacterial counts in 54 wheat samples ranged from 870 to 3,100,000 per gram. In most of the samples, fungal counts were less than bacterial counts, but still present nonetheless.

Further, during the making of a documentary by National Geographic, a man named Ed Wood (author of “World Sourdoughs From Antiquity”) attempted to establish a starter with sterilized flour. He failed repeatedly. Although a few of his samples succeeded, it was concluded that sterilized flour sharply reduced the odds of creating a thriving starter.

White flour in a glass bowl

Millions upon millions of microscopic bugs


4. Starters cannot be created with bleached flour or chlorinated water

Incorrect. It’s possible to establish a starter with bleached flour and/or chlorinated water.

In general, if the water is acceptable for human consumption, it’s acceptable for starters as well. If the presence of chlorine is still a concern, boiling or leaving the water to stand for several hours will eliminate the chlorine. However, water containing other obstinate forms of chlorine, such as chloramine, may cause problems for sourdough. In this case, bottled spring water or natural mineral water may be a practical solution.

Faucet with tap water running

If it’s good enough for you, then it’s good enough for sourdough


5. Sourdough must be sour

Nay. Several techniques can be used to remove or reduce the tang in sourdough. All things considered, the degree of sourness in sourdough is an issue of cultural and personal preference. For example, San Francisco sourdough in the U.S. is distinctively tangy, whereas pain au levain (a French legal term meaning “bread of leaven”) in France has a subtle to mild acidic flavour.

Girl with mouth-puckering, sour face

You may expect this reaction when people eat sourdough for the first time
(Photo courtesy of Karen)


6. The addition of fruits, vegetables, yeast, etc. can help establish starters

On the contrary, the addition of fruits, vegetables, yeast, and so on hinders the growth and stability of starters. The most apt microorganisms for starters are grain-based. Therefore, flour and water is enough to establish a healthy and effective starter.

One exception is the temporary addition of fruit juices. Fruit juices can deter the growth of foul smelling bacteria in newborn starters. However, this is not necessary as regular feedings of the starter will eradicate such bacteria in due time.

A bunch of black grapes

Feeding sourdough with fruits is like feeding cows with corn;
they’re not adapted to it


7. Older starters are better than younger starters

Untrue. Once matured, younger starters perform just as well, if not better, as older starters. In fact, it’s common practice amongst bakers in Germany to redo their starters every 6 months to maintain its liveliness and vitality.

Moreover, if the starter is fed frequently and regularly, microbial generations in the starter will renew every few hours. Therefore, the original microorganisms occupying the starter are long expired and succeeded by their descendants or competitors.

Young & Old Hands

The young are just as strong as the old


8. Starters are highly susceptible to local or regional microorganisms

Negative. A sudden change of behaviour or flavour in starters, often occurring when moving from one location to another, may be wrongly attributed to local microorganisms taking over the starter.

Starters remain stable if they are fed regularly and environmental conditions do not fluctuate significantly. Any substantial changes in temperature, humidity, altitude, feeding schedule, and other factors will alter the starter’s behaviour and/or flavour.

Moving Packed Boxes

Nobody likes the stress of moving places


9. Different temperatures and hydration affects different types of bacteria in sourdough

Inaccurate. Certain temperatures and hydration (ratio of water to flour) do not stimulate or deter the growth of certain types of sourdough bacteria. Rather, certain temperatures and hydration encourage sourdough bacteria to take certain metabolic pathways.

On the subject of sourdough, Debra Winks, a microbiologist, states the following: “Wetter and warmer conditions favour more homofermentation in the facultatively heterofermentative bacteria (facultative, meaning that they are capable of both), and more alcohol (instead of acetic acid) in the obligately heterofermentative bacteria. Cooler and drier increase acetic acid output in both types, but it’s the same (heterofermentative) bacteria either way.”


1: Could 100-Year-Old Sourdough Be a Myth? BBC.
2: Five Things You Thought You Knew About Sourdough. Wild Yeast.
3: Front Page on Wall Street Journal. The Fresh Loaf.
4: Microflora of Wheat and Wheat Flour from Six Areas of the United States. Cereal Chemistry. [PDF]
5: Pain au Levain Production. Lallemand. [PDF]
6: Starters Using Bleached All Purpose Flour. The Fresh Loaf.
7: Starting a Starter. Sourdough Home.
8: Sourdough Myths and Folklore. Sourdough Home.
9: Taxonomic Structure and Stability of the Bacterial Community in Belgian Sourdough Ecosystems as Assessed by Culture and Population Fingerprinting. Applied and Environmental Microbiology. [PDF]
10: The Biology of … Sourdough. Discover.
11: The Sourdough Microflora: Biodiversity and Metabolic Interactions. Trends in Food Science and Technology. [PDF]

Author: Zita (bakingbadly)
Published: June 20th, 2014
Last Modified: July 20th, 2014

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