The Sourdough Journey

If any of you are interested in the Sourdough Sidekick which I posted here yesterday, there is a FB group called Sourdough Sidekick. I’ll be posting daily updates there as I test the unit, then I will do a summary post here in a few weeks.

My posts are in my name in that group, I cannot join the group as this “page,” or link the posts to this page.

There is a lot of great info in that group. Some bakers have been using the unit for about 1-2 months now.

Bulk Fermentation Part 3: Origins of the Two-Factor Method

I began baking sourdough in 2019, and I was largely following Chad Robertson’s Tartine Bread method. Tartine was one of the first methods to measure the “percentage rise” in the dough as a cutoff criteria for bulk fermentation. The method recommends a 30% rise in the dough before preshaping. This is a fairly low rise.

At the same time, I was familiar with Elian Boddy’s method where she recommended letting the dough “roughly double” in volume. Ken Forkish recommended letting dough “double or triple” in volume before cutting off bulk fermentation.

Many bakers asked, “How could all of these methods work with such different guidance in the bulk fermentation cutoff?”

I began experimenting with different approaches when I realized the difference was related to dough temperature.

Chad Robertson recommended bulk fermenting the dough at a very warm temperature of 78-82F (26-28C). Elaine Boddy didn’t specify a dough temperature, but generally was bulk fermenting overnight in her kitchen with temperatures around 70F/21C. Ken Forkish similar did not specify his dough temperature, but was bulk fermenting overnight at even cooler temperatures then Elaine.

I started experimenting in my kitchen and quickly came to the following conclusion:

“Warm dough needed to be cut off earlier then cool dough because warm dough keeps rapidly fermenting in the downstream steps (shaping and final proofing — even in the refrigerator).”

I then ran dozens of controlled experiments and arrived at this basic guidance:

At 80F/27C dough temperature, cut off bulk fermentation at a 30% rise
At 75F/24C dough temperature, cut off bulk fermentation at a 50% rise
At 70F/21C dough temperature, cut off bulk fermentation at a 75% rise
At 65F/18C dough temperature, cut off bulk fermentation at a 100% rise

This was the origin of the “Two-Factor Method” of using the combination of dough temperature and percentage rise to determine the cutoff of bulk fermentation. The method also became known as “The Percentage Rise Method,” and the “Dough Temping Method.” Over the years, I have refined this simple, initial guidance into a comprehensive method with guides, videos and tools. (The guidance shown above is a low-end estimate, and a good starting point for most bakers).

This was an extraordinary breakthrough at the time. The vast majority of sourdough books and methods recommended “let the dough double in size” for the cutoff of bulk fermentation, and few if any, recommended a specific dough temperature. Worse yet, many recipes simply gave bulk fermentation timing guidance (e.g., 6-8 hours) with no reference to dough temperature or the target percentage rise.

Beginning sourdough bakers struggled immensely because none of the popular recipes or methods described the impact of dough temperature on bulk fermentation, or the association with the target rise.

This may all seem obvious now, but at the time, I was the only sourdough baker/educator describing this relationship between dough temperature and the target percentage rise in the dough. Today, these methods are widely used among sourdough bakers.

Here is the video from 2021, where I first tested and described this relationship. If you just want to watch the summary, I recommend starting at 1:06:00. This link will begin the video there. https://youtu.be/HTKrdSOUJWs?si=fZlaA3JmaCLsr3qG&t=4012

Here is the paper I wrote, summarizing my findings in January 2023. https://thesourdoughjourney.com/the-mystery-of-percentage-rise-in-bulk-fermentation/

Here is a video from 2024 describing the Two-Factor Method in detail. https://youtu.be/p69UMuYJhJs

Here is a post with the popular chart, video and guide. https://thesourdoughjourney.com/dough-temping-for-perfect-sourdough-fermentation/

©️The Sourdough Journey, 2026

Bulk Fermentation Part 2: How did our grandparents make sourdough?

When I created the “Two-Factor Method” of assessing the bulk fermentation cutoff by looking at the percentage rise and dough temperature, many people said:

“You’re over complicating things. How did our grandparents make sourdough without thermometers and measuring vessels?”

In reality, this method is probably the closest to how home bakers made sourdough many years ago.

Imagine a home baker with one measuring cup, one favorite bowl, and following the same sourdough bread recipe every day.

After mixing the dough, they would simply watch the dough rise in the bowl. And, they would also typically be very aware of their kitchen temperature (many had a mercury thermometer on the wall in their kitchen).

- If you watch the dough rise in the bowl, you can very quickly assess how much the dough has risen, and develop an eye for exactly how much it should rise in the bowl before it is finished bulk fermenting (before shaping). When you follow the same recipe and use the same mixing vessel every day, this becomes quite easy with a quick glance at the bowl.

After experiencing a few seasonal changes of baking experience (and/or based on learning from another baker) the home baker would quickly learn a few simple rules:
- In a warm kitchen, the dough rises faster, in a cool kitchen it rises more slowly
- With cool dough, you can let it rise much taller than when it is warm
- Warm dough needs to be cut off and shaped earlier because it will keep rapidly fermenting during and after shaping.

This is the essence of the “Two-Factor Method:”
1. Measure the temperature and percentage rise of the dough
2. Cut off the rise earlier for warm dough and later for cool dough
3. The “ending” dough temperature carries forward into the shaping and final proofing steps (countertop or fridge) so the percentage rise and dough temperature need to anticipate the downstream steps when determining the bulk fermentation cutoff.

Tomorrow’s Post: The Origins of the Method

In my next few posts, I’ll be discussing the “Two-Factor Method” of using your dough temperature and the percentage rise in the dough to determine the cutoff of bulk fermentation.

This method, also often referred to as the “Percentage Rise Method” or the “Dough Temping Method,” is something I created in 2022.

Let’s start with the basics of how the method works.

Dough temperature and the percentage rise in your dough are two of the most useful tools for assessing how your dough is fermenting.

The dough temperature indicates the “speed” of your fermentation (like a speedometer).

The percentage rise of the dough indicates the “distance traveled” in your dough (like an odometer).

When repeating the same recipe and process, the percentage rise in your dough is a very repeatable method for determining how far along your dough is in the fermentation process.

When people say “ ignore the clock and watch the dough,” the percentage rise in the dough is one of the best indicators for assessing bulk fermentation, even as the timing may vary day-to-day due to other factors like dough temperature and starter strength.

©️The Sourdough Journey, 2026

The Bread Winner Summit starts today!

I am pleased to be participating in the 2026 BreadWinner Summit for sourdough micro-bakers.

The two-day virtual event on June 1-2, is hosted by Caroline Bower, and it features interviews and presentations from 16 sourdough bakers and educators.

The two-day, live event is FREE just by signing up using the link below.

If you sign up for free access, you can view the contents of the summit live, and the recordings for 48 hours after the close of the summit.

If you upgrade to the All-Access Pass, you’ll have lifetime access to this year’s recorded content, and you get access to downloadable tools, and dozens of discounts and special offers. The price of the all-access pass is $97. (Disclosure: I receive a commission on these sales if you use this link).

https://thesourdoughjourney—carolinebower.thrivecart.com/2026aap/

Last year’s Summit was excellent. Caroline does a fantastic job putting this event together, and I love how it supports small businesses, and sourdough home bakers who are moving into production baking at all levels.

Here is the schedule of events.

Note: The times are U.S. Central Time. My session on Bulk Fermentation is live at 11am CT on June 1.

I am pleased to be participating in the 2026 BreadWinner Summit for sourdough micro-bakers.

I was a keynote speaker at this event last year, and I will be returning as a speaker this year.

The two-day virtual event on June 1-2, is hosted by Caroline Bower, and it features interviews and presentations from 16 sourdough bakers and educators.

The two-day, live event is FREE just by signing up using the link below.

If you sign up for free access, you can view the contents of the summit live, and for 48 hours after the close of the summit.

If you upgrade to the All-Access Pass, you’ll have lifetime access to this year’s recorded content, and you get access to downloadable tools, and dozens of discounts and special offers. The price of the all-access pass is $97. (Disclosure: I receive a commission on these sales if you use this link).

https://thesourdoughjourney--carolinebower.thrivecart.com/2026aap/

Last year’s Summit was excellent. Caroline does a fantastic job putting this event together, and I love how it supports small businesses, and sourdough home bakers who are moving into production baking at all levels.

Here is the schedule of events.

Note: The times are U.S. Central Time. My session is at 11am CST on June 1.

If you haven’t had a chance to listen to this podcast, please check it out.

I’ve done quite a few podcasts in the past, and I think this is the most interesting content I’ve covered.

Erik Fabian is a great interviewer, and Eric Pallant, author of “Sourdough Culture,” is a wealth of knowledge.

I also highly recommend Eric’s book if you are interested in the history of sourdough.

Cookbook Debate: Tartine Bread (w/ Tom & Eric) Podcast Episode · Bake This Book · May 12 · 59m

Here is some innovative, new content coming out from Elaine Boddy at Foodbod Sourdough.

It’s great to see new, creative, human-generated content standing above the flood of useless, rehashed content coming from AI.

Elaine’s books are great, and her recipes are simple and delicious.

It will be available later this year in the U.S. It’s never too early to start thinking about holiday gift ideas for sourdough bakers!