The Sourdough Journey

Here is a sneak preview of an interesting experiment I've been working on for one-and-a-half years.

I purchased a mature, bakery starter in February 2025, and I maintained it differently in my home for 14 months.

At the end of the 14-month period, I sent both starters to a lab for DNA testing.

How much do you think they changed?

I'll post the results in the coming weeks.

This is a very interesting study from 2025 that I had not seen until now.

https://journals.asm.org/doi/epub/10.1128/spectrum.02380-25

The study compares the impact of different flours and different feeding methods when creating a new sourdough starter from scratch.

The study team created 18 new starters over a 28-day period using three different types of flour (AP, Bread, Whole Wheat) and two different feeding methods (every 24 hours, and every 48 hours).

They used DNA sequencing to assess the microbes in the flours, then they assessed the change in DNA of the various starters to assess how the starters' microbial populations change as the starter develops in its first month of maturity.

A few interesting findings:
1) The feeding protocol did not have a material impact on the microbial population
2) The source microbes in the bread flour and all purpose flour were very similar, the whole wheat flour was quite different.
3) The same dominant yeast genus (Kazachstania) appeared in all of the starters. At the end of the study, a few samples included the yeast genus Saccharomyces (commonly found in many sourdough starters).
4) Saccharomyces did not appear in detectable quantities in the three flour samples. It possibly arrives in the starter through another vector (air, water, surface contact, etc.)
5) It took more than seven days for material populations of yeast and lactic acid bacteria typically found in sourdough starters to develop.

In 2023, I tested many popular starter creation methods, and I created 40 new starters from scratch that year, under highly controlled conditions. Many of the study findings comport with my observations. I generally recommend using a 50/50 mix of bread flour and whole wheat flour when creating a new starter (or 25% rye and 75% bread flour). It generally takes 7-14 days to establish a new starter from scratch. New starters continue to materially evolve over the first month, and I believe they reach a type of stability after about one year (but then always slowly change over time). Sourdough starters are an "open" microbiome, and incidental cross-contamination from other starters or sources is likely very common.

My main concern with drawing too many conclusions from the recent study is due to the use of highly processed supermarket flours (Gold Medal Brand), which in my experience, I found to be quite "lifeless" flours for purposes of creating a new starter. I would speculate that a fresher, stone ground whole wheat flour for example, would show a very different microbial taxa and a different development timeline. Just my speculation based on similar experience.

There are some interesting charts in the study which show the profile of microbes found in the flours, and charts showing how the microbial populations of the sourdough starters changed over the 28 day study period. These are interesting. Note, many of the microbes found in the flour are environmental microbes found in soil, and they eventually are "washed out" of a sourdough starter as the bacterial populations create a more acidic environment with a low pH. You need to download the the PDF to clearly read these tables.

Notably, many of the yeast and bacteria species presumed to be desirable for sourdough starters (e.g., S. cerevisiae and Fr. sanfranciscensis) are not found in detectible quantities in the flour. This is quite fascinating. Two hypotheses are that they enter a starter through another vector (air, water, human hands, surface contact/contamination), or they exist in very small populations in the flour, and they slowly emerge in a new starter over time.

I have not studied this report in great detail, so I am interested in your reading and feedback.

I've also attached to (unverified) images from ChatGPT explaining the nature of the various fungi and bacteria shown in the charts.

You can create a new sourdough starter with almost any type of flour, but in my experience, you’ll have the best chance of success when using whole grain flour.

I recommend a 50/50 mix of whole wheat flour and bread flour. You can also use 25% rye flour and 75% bread flour.

You can also substitute all-purpose flour for the bread flour portions above, if needed.

The dormant yeast and bacteria cells needed to activate a new starter are more likely to be found in whole grain flours than in refined flours.

Over the years, I have tested 40 different methods of creating sourdough starters from scratch.

Once your starter is established, you can typically transition to feeding it 100% bread flour.

For all the details, guides and videos on how to create a new starter, check out https://thesourdoughjourney.com/faq-starter-creation/

©️The Sourdough Journey, 2026

Ooni is coming out with a smaller, cheaper version of their popular spiral mixer.

4.8L capacity for $599.

Still a bit pricey, but many people love the full-size Ooni Halo.

I don’t own either of these devices.

https://www.facebook.com/share/1BVeYeEych/?mibextid=wwXIfr

The spiral mixing secret is out Be first in line on launch day

I am doing some research on how a sourdough starter’s microbial population can change based on different maintenance routines.

I don’t recall if we have any microbiologists in this group.

I am particularly interested in the work of Michael Gänzle and Rob Dunn’s team at NCSU on “Type 1 and Type 2” starters.

If anyone has background in this area and would like to discuss, please comment below.

For others interested in this topic, this video with Michael Ganzle is fascinating. The audio quality is not great but if you turn on captions it helps.

Michael Ganzle 14 June 2021 Professor Michael Ganzle on the science of sourdough starters.

“Saving Bread” is a new sourdough podcast, hosted by Allison White. Please check it out.

I will be featured in an upcoming episode. Details to follow.

Saving Bread Food Podcast · A podcast about baking, grain, fermentation, craftsmanship, and the people keeping the traditions of real food alive.

This loaf unexpectedly spent five days in the refrigerator.

It had a spectacularly soft, tender crumb, and super sour flavor.

I typically do a 12-24 hour cold re**rd of my shaped loaves. Occasionally I’ll push the cold final proof to 3 days if I’m seeking a sour loaf.

After three days in the fridge, my loaves typically begin to deteriorate, and the flavor can shift toward more bitterness than sourness.

This loaf had a spectacularly sour aroma and flavor. The flavor was sour and complex. The flavor finish was bright with hint of vinegar.

The loaf lost some height and structure with the long cold re**rd. The crumb indicates the loaf is overproofing, but the flavor and texture was amazing.

©️The Sourdough Journey, 2026

A July 4th Sourdough Tradition…

In July 2023, my brother Bob and I wanted to make a humorous sourdough instructional video. A few days of mayhem ensued. We made a funny, educational video — and an homage to some of the favorite films of our youth.

“ A masterpiece.”
“The funniest sourdough video ever made.”

There are over 30 popular film references in the video. Can you spot them?

The Sourdough Brothers: Sourdough for Busy People

NEW!: The Sourdough Brothers: Sourdough for Busy People The Sourdough Brothers return for the most epic sourdough video eve...