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Sourdough Rise Time Table

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bwraith's picture
bwraith

Sourdough Rise Time Table

I've had a number of discussions with TFL participants recently about sourdough rise times versus temperature and inoculation. Temperature has a big effect on sourdough rise times, and sometimes a starter appears unhealthy, when it is really just rising more slowly because of low temperatures in the kitchen during winter. Also, recipes that used to work seem to fail during the winter, but the colder temperatures may be the cause. To adjust for cold winter kitchen temperatures, either the temperature must be managed actively (oven with pilot light or electric light, coolers with a bowl of warm water in them, and so on), or the percentage of fermented flour must be adjusted in the recipe, or much more time must be allowed for the bulk fermentation and proofing.

I constructed a table that provides (in hours) the doubling time, bulk fermentation time, proofing time, and total mix-to-bake time for various temperatures and percentages of fermented flour. The table has two sections, one for no salt meant for unsalted levains, and one for 2% salt meant for doughs or salted levains.

Inoculation, as used in the table, is the percentage of fermented flour contributed by a levain or storage starter to the total flour in a levain or dough. For example, if 50g of storage starter at 100% hydration is contributed to 225g of flour and 175g of water to create a levain, then the total flour is 250g (25g+225g) and the percentage of fermented flour is 10% (25g out of 250g total flour). Similarly, if a dough containing 1Kg of total flour is made by contributing the levain just mentioned to 750g of flour and 550g of water and 20g of salt, then the inoculation or percentage of fermented flour is 25%, or 250g out of a total flour of 1Kg.

The table is made to match up to rise times for whole wheat, high extraction, or generally high ash content flours I tend to use in my sourdough hearth breads. For pure white flour doughs and levains, the times tend to be about 20% longer, i.e. white flour rises a little more slowly.

Your starter may well be faster or slower than mine. If you build a test levain using a representative entry in the table, such as 10% at 75F, you can see how your starter compares to these table entries and then adjust your rise times and proof times up or down by the same percentage. For example, if you starter doubles in 80% of the time indicated in the table, then it makes sense to use 80% of the time in the table for other temperatures and inoculations also.

You can see from the table that the rise times vary over a huge range depending on temperature. Also, inoculations need to be changed drastically for long overnight rises, depending on temperature.

The strategy for maintaining a starter should also change dramatically if the temperature is 65F instead of close to 80F in the kitchen from winter to summer. For example, a 25% inoculation at 65F results in a 10 hour mix-to-bake time, which is a couple of hours before a levain would peak and begin to collapse, but at 80F an inoculation of only 0.5% results in a 10 hour mix-to-bake time. I've used this model at wide ranges of temperature and had reasonable results. The interesting thing to notice is that a 20g:30g:30g feeding at 65F peaks in around 12 hours but a 1g:100g:100g feeding at 80F peaks in around 12 hours, too. Or, if you look at the mix-to-bake time at 65F for a 10g:45g:45g feeding (10% inoculation), it's 12.5 hours, so if you feed that way at 65F the starter won't be getting to its peak and may be overfed if the feeding is repeated every 12 hours, while the same feeding at 80F will peak in less than 8 hours, so a 12 hour schedule will work well at that temperature.

This is simplified from my rise time models, so it doesn't include some additional adjustments for the dough consistency I make in my spreadsheets. Of course, this is a very rough approximation. All kinds of complications may cause these numbers to be different from actual results. So, it's just a guideline and something to think about, and it's biggest use may be as a learning tool or to just get in the general ballpark for rise times. For example, if your temperatures are very different from the ones the author assumed in the recipe, or if you just don't have an idea where to start with rise times for some recipe your trying, maybe the table will help.

Apologies in advance, if it turns out there is a bug in the table somewhere, but at least some of the numbers made sense after browsing through the table.

Comments

edh's picture
edh

Bill,

Thank you so much for re-posting this table; I remember you posting it before, but it went right over my head, so I promptly forgot about it!

I'm still trying to revive my sluggish pet, but it's coming along so I think I'll be able to run a test and compare it to your table soon.

Thank you so much for all your help on these things! You are incredibly generous with your time and knowledge to those of us flailing around in the flour and water...

edh

ejm's picture
ejm

Many thanks for this, Bill!

 

I will stare at the table. (I'm afraid I am on overload right now and seem incapable of comprehending the numbers. So much for having been an honours student in math and science....)

 

-Elizabeth 

 

P.S. And I thought that breadmaking WASN'T rocket science. ;-)

bwraith's picture
bwraith

edh,Elizabeth,

I hope the table may help, even if just to put rise times in perspective vs. temperature and to understand how rise time varies with the percentage of fermented flour initially contributed to a dough or levain. I never posted this table before, but I posted a spreadsheet with some of the same models in it. I think the table is nice because anyone can use it without downloading a model and figuring out my inputs. Also, you can make your own adjustments to what it suggests, once you know how your starter and flours vary relative to the table results.

The table has groups of 4 numbers for each temperature (you can see temperature on the left side) and inoculation (the percentage of fermented flour across the top row). There are two tables side by side. The one on the left is with no salt, the one on the right with 2% salt.

The four numbers are:

  1. The time to double in volume in hours.
  2. Bulk fermentation time in hours (somewhat less than a doubling).
  3. Proof time in hours.
  4. Total mix-to-bake time in hours. 

In order to not overproof, the total mix-to-bake time should be from the moment you mix the fermented flour with the rest of the flour until you put it in the oven, including all kneading, shaping, scoring time. This is because the fermentation is going on during all that time, and you don't want it to go on any longer than the right amount of time.

Remember that white flours are generally slower to ferment than whole wheat or partially whole wheat flours. Wetter doughs will ferment a little faster than firmer ones. Everyone's starter is a little different. So, these are rough guidelines for a typical starter (mine) and a typical dough - not too wet, not too firm.

Bill

 

ehanner's picture
ehanner

Hi Bill,

Could you take a look at your sourdough timing table. It doesn't seem to load for me.

Thanks,
Eric

BakerBen's picture
BakerBen

Bill,


Quick question concerning table value - at a given temp as the inoculation % increase the mix to bake time decreases and the bulk fermentation also decreases - this is intuitive and makes sense to me. I am having a problem understanding why as the inoculation % increases the "proof time" also increases - it seems it should be decreasing due to the higher % of inoculant. I must be missing something - can you help explain this to me? This is a great aid - one I have been thinking about and looking for for a while - thank you for sharing your work.


Ben


 

GregS's picture
GregS

Is the actual "live" Excel (I presume) file available for download? It would be more compact and manageable than the five images in the posts. Either way it is a work of art. Thank you!


Greg

ryechief's picture
ryechief

I am trying to work out a schedule that will allow me to delay a couple of sourdoughs. I greatly appreciate the work you have put into the table and am very interested in what happens at fridge temperature. Will get back to  you with results. Thank you for the guidelines!

thomaschacon's picture
thomaschacon (not verified)

Every once in a while, I encounter something so helpful on The Fresh Loaf that I want to bounce right out of my chair.

Such is this table of data.

(I couldn't find the link to the table at first, it's here: http://www.wraithnj.com/breadpics/rise_time_table/bread_model_bwraith.htm)

Two Three questions.

1. If the final dough has the following composition:

  • 1000 g of flour, of which 25% (250 g) is prefermented
  • 2% salt
  • 75 F
  • What is 4.14 hours = ?? (I know it says to use this value to compare against my starter and adjust accordingly, but I'm not sure I fully understand what that means). If my starter is, for example, 10% faster, or has a doubling time of 4.554 hours, would the following be correct:
  • 3.25 hours * (110%) = 3.58 hours Bulk fermentation time
  • 2.84 hours * (110%) = 3.12 hours Proofing time.
  • 6.09 hours * (110%) = (3.58 + 3.12) =  6.7 hours Total time, mix to bake.

2. Why does the spreadsheet stop at 25% prefermented flour? I regularly make breads with 40% prefermented flour. I'm worried that, because it stops at 25%, I'm completely misinterpreting the purpose of the data (or at least the part that says "Inoculation is the percentage of fermented flour to total flour in the dough or preferment when it is first mixed.") My example above (250 g prefermented flour of 1000 g), then I should be looking at the 25% column, yes? (It's the term innoculation that's confusing me, as I use that term for adding seed culture to flour and water to build up a starter. I innoculate some flour and water with a seed from my mother starter. When I add the preferment to the final or intermediate dough, I don't call it innoculation, although I guess I should? Is that what you mean my innoculation here, just adding preferment to final or intermediate dough?)

3. Is the spreadsheet with cell formulae available for download, so I can see that math? If so, maybe I can extend the spreadsheet for myself to 50% prefermented. If not, how are the data derived?

Again, much thanks. If I'm understanding the data correctly (and the data are accurate), if could take a lot of trial and error out of my sourdough time estimates.

Thanks,

Thomas

bwraith's picture
bwraith

Well, I know it has been a very long time, so you may no longer care. I happened to log back in to check something and saw this. I guess I missed the original notification somehow. As to question 1, yes that is my model's guess at the time it will take for the dough to double in volume. I think the any of the times would be proportional for a dough with a different doubling time, just as you describe.

 

As to question 2, my model has trouble predicting situations where the percentage of fermented to total flour is higher than 25%, since it is really just a guess at the growth rate of the culture based on a lot of experimentation I did at one point. I essentially codified the growth rates as a function of temperature, salt, hydration, and so on, but the average growth rate slows down dramatically as the culture becomes saturated. My model doesn't really handle that, as I did no experiments and did not fit any data for very high fermented flour percentages. I have used my model for a variety of hearth breads from ordinary to focaccias and pizzas to bagels with good predictions. In particular, I find the model extremely helpful to predict long fermentation at cool temperatures, when the accumulation of growth can vary by hours as a function of temperature and time in the refrigerator or incubator.

If I were to start over knowing what I know now, I would start with a model that integrates the growth rates and pays no attention to "doubling of volume" but instead tries to predict the accumulation of acid over time. I have read some papers on the subject and it wouldn't be that difficult for someone with some time to make a model with the same basic structure as mine for the inputs and outputs, but with an underlying concept of accumulating a varying growth rate, as conditions vary with that growth. 

3. Unfortunately, I don't think my model would help that much since it is really based on the relatively constant growth that would occur during the phase when the dough is at lower concentrations of organisms. However, maybe you could extend the tables, if you did your own experiments. I would think the above suggested approach integrating the growth rate would be a much more flexible model that would cover a much wider range accurately and more intuitive to build, as well.

I am posting a link to a shared Google Spreadsheet. i don't know if it will work, as there are functions that would need transfer along with it, but I now only use my models in Google Spreadsheets. Hopefully, you could copy this spreadsheet and use as you like. There are many flaws with the approach in retrospect, yet I have used it, as I said, for many different dough recipes.

Sourdough Bread Spreadsheet by bwraith

Mini Oven's picture
Mini Oven

<help>

bwraith's picture
bwraith

I was updating my server, but I think the links are there again, although I am only a few minutes past having rebuilt it.

Mini Oven's picture
Mini Oven

Hi Bill and thanks,  I think we got some kind of esp connection...  that was fast!   Thank you again, Mini

PMcCool's picture
PMcCool

It's been a long time since I've seen anything from you and it's a pleasure to know that you are still above ground.  Hope to see more from you.

Paul