The Fresh Loaf

A Community of Amateur Bakers and Artisan Bread Enthusiasts.

Time and Temperature

davidg618's picture

Time and Temperature

I have a question I've not been able to answer to my satisfaction after searching online and favorite books. 

Many of my bread bakings begin with someone elses formula wherein I convert  or modify either ingredients and/or procedures.

The two changes I'm frequently unsure of are:

How much natural levain do I need to substitute for the commercial yeast called for?

How much should I reduce the called for levain (any type) when I adapt a straight dough, room temperature fermented to a chilled, retarded fermentation? And a variation of the question: converting a straight dough, room temperature fermented to a poolish or biga, and also chilled and retarded fermentation.

To date, I've had success doing all these changes, but formulae I bake routinely took a number of iterations to refine to a finale, and ones I've baked only once or twice have sometimes been less than what they might have been.

Can anyone point me at a book or online source for better guidance than trial and error, or share some rules-of-thumb with me?

Oops. I should also say I keep the original formula hydration the same.


David G

jcking's picture

Dave, Poolish, Biga or Sourdough on average are 20 to 30%of the total flour. It helps to set up an Excel spread sheet to help with the calculations. Remember Total Flour because a poolish is wet, a biga is dry, and storage sourdough could be either.


davidg618's picture

I routinely use a spread sheet I developed three + years ago to do the math for  me. It accounts for differences in starter hydration vs. final hydration, and calculates baker's percentage for all the doughs ingredients.  It serves me well for formulating new breads, translating volume only recipes, and converting. Nonetheless I've replied to your message affirmatively, I am always open to learn.

I wasn't sure when I wrote of my wishes, if I could make myself clear. I guess I wasn't.  I'll give you an example. My starter is maintained with KA Bread Flour at 100% hydration. I routinely make a nearly all white (10% Whole Rye, 90% 50:50 mix of KA AP and Bread flours), final dough is 68% Hydrated. Only 14% of the flour is prefermented (all Bread Flour)  feeding the levain builds. I also retard this dough 15 hours at 54°F, and I set the DDT to the same 54°F and hydrate with ice water, except for the water in the levain (also 14%) which is at room temperature. I begin chilling the dough immediately, placing the newly mixed dough in the refrigerator where it remains, except for post autolyse machine mixing, and/or S&F's. Once the dough reaches DDT, usually achieved within the first two hours (it usually starts at 62°F to 64°F due to machine mixing friction) it goes into the wine chiller for the remainder of the retarding duration. Subsequently, I divide the dough immediately when removed from the chiller, preshape the loaves, and rest them for 1 hour at 82°F in a proofing box. I then shape them and all shapes except baguettes are returned to the proofing box at 82°F. The loaves complete proofing (based on poke test) in 2-1/4 to 2-1/2 hours.  Baguette shapes are proofed at room temperature because they are too long for the home built proofing box.  The proofing times are in the same order of analogous sourdough loaves made with 25% of the flour prefermented feeding the levain builds,  bulk fermented for 6 or 4 hours at room temperature or 82°F, and proofed for 2 to 2- 1/4 hour at 82°F The point of all this is at only 14% I'm already far below the low side of general guidance, yet my results are spot on.

I also get similar performance with commercial yeast in a baguette formula. I put a scant 1/8th of a tsp. of IDY in a twelve hour poolish ripened at room temperature, mix the all white dough, and retard for 15 hours at 54°F. The original formula specifies an additional 3/4 tsp IDY in the final dough. I use half of that, 3/8 tsp. The dough doubles in volume overnight. I handle it as above, except the shaped loaves proof at room temp (76°F in summer, 68°-70° in winter.) Final proofing takes ~75 to 90 mins. The original poolish, non-retarded recipe specifies 45 to 60 minutes (I've only made it once per the original, and I don't have a record of the proofing time realized). 50% of total flour is prefermented in the poolish in both cases.

These are two doughs I make routinely, both went through a number of iterations until I settled on the percentage or volume shown.

Recently, I converted the baguette recipe to natural levain, and converted a straight dough, commercial yeast bagel recipe to natural levain. The formula already specified an overnight retardation.  In both cases I could only guess at the IDY to natural levain conversion.  I'm still tweaking the baguettes, but I'm happy to say my guess with the bagels was pretty darned good luck.  Those experiences triggered my questions.

 I think I'm hoping there exists a chart, or rule-of-thumb that suggests how much IDY or % of natural levain to reduce for each hour of  chilled retardation over a modest range of temperatures, and a rule-of-thumb that states 1 tsp of IDY is approximately equal to X gms (or a small range of grams) of robust, ripe natural levain. I'm probably whistling in the wind.

David G

jcking's picture


I haven't found any charts or formula to account for a chilled retardation. What I can say is it takes about an average of one hour for the yeast activity of a dough retarded, to slow to an almost stop at 40°F. The main reason for chilled retardation, as I have found stated by professional bakers on the Bread Bakers Guild of America, is to plan production for an early morning bake. Any flavor gained by this is bacterial action. Each bakery makes adjustments for retarding based on what they have to work with and no two bakeries are identical.

Any recipe/formula I have read reduces bench time prior to chilled retardation, for either bulk fermentation or proofing, to be reduced.

I'll send you a text file to read. Jim

davidg618's picture

I am convinced from repeatedly mixing with low DDT, and bulk fermenting my doughs 15 to 21 hours at 52° to 54°F  they achieve considerable flavor development during that period: both sourdoughs, poolish-fortified doughs, and straight doughs.

I am very aware of the flexibility retarding dough lends to scheduling. I schedule levain building; dough manipulation, and fermentation; and baking to not interfere with my other commitments, relaxing and a good night's sleep.

Have you read or baked Reinhar's Pain a l'Ancienne formula in The Bread Baker's Apprentice? This is where I began my exploration of lowered (from the conventional 76°F) DDT  and chilled, retarded fermentation.

And, at the risk of offending, I entirely disagree with your statement "Any flavor gained by this is bacterial action."

I look forward to reading the text.

David G

jcking's picture


As far as the "any flavor gained by this is bacterial action", applies to either some bulk fermentation or profing at room temperature and a retarding at 40°F. I see now your technique is somewhat different.

I agree longer fermentation times will result in improved flavor. And Pan a L'Ancienne has wonderful flavor. Just remember we're dealing with acidic flavor from bacteria, long fermentation and sourdough, and the sweet sugar development of the Pan a L'Ancienne. For those reading this post the Pan a L'Ancienne is quickly refrigerated so the yeast sleeps, while the flour breaks down and provides a greater amount of sugar for the yeast to feed on, upon waking/warming up. And I now see you're combining the two, great idea. It's funny before reading your latest post I was placing flour in the fridge for a Pan a L'Ancienne bake tomorrow.

I'm assuming your retired as myself and can devote time to our experiments to achieve flavors that a professional bakery may find cost prohibitive. For the Artisan Bakery it's a balance of what the customer's willing to pay, provide a great bread and still make a profit.

As an aside, I've playing around with a two part SD build; one for yeast activity and one for bacterial flavor.

Great conservation you've got me thinking, Jim

dabrownman's picture

on the Internet for these conversions or a spreadsheet but I can tell you how I do it and what I think about.  I too use a spreadsheet for every recipe since I rarely bake a bread from another recipe due to the changes I want to make.  But spreadsheet s and percents are only 1/3 the thought needed.  Time and temperature are the other 2/3rds.  If I am converting from commercial yeast, biga or poolish to SD and want a less sour bread, I will take 20% of the total water and flour in the recipe and build my SD levain over 2 builds throwing nothing away and using 20g of 100% hydration starter.   The less sour I want the less time I retard the levain and dough since Labs reproduce at 3 times the rate that yeast does at both low 36 F and high temperature 85 F - even though at high temps the yeast is reproducing wildly too - just 3 times less than the Labs. 

I'm guessing that David Snyder's small seed to larger flour water ratio for levain, longer low temperature retard low and high final proof temp when he wants sour in his SFSD is based on these notions - more labs to yeast means more sour and longer the LABs can work at low temp without yeast making the dough rise is good.  Then boom a short 85 F final proof gets the dough to rise quickly before it turns to goo and the Labs are also making the dough much more sour too and very quickly.

If I want a more sour bread I might take the same amount of flour and water and only use 10 g of starter tpo make sure that the yeast can work on more flour longer to increase the sour.  I also might take 30 - 40 g of starter to create a larger inoculation, go a longer 3 build schedule for the levain and use a larger % of total flour and water for the levain up to  40% knowing that more Labs in the total will make for a sour bread.  Or, I might just let the dough retard for up to 40 hours bepending on what flours are being used knowing that longer retard means more sour. 

The most sour bread I have created was with 10% of the water and 10% of the water (100 g total) mixed with 1 g of starter that had been refrigerated for 3 days at its peak and allowed to double in one build - about  24 hours in the summer in a 80 F kitchen.  Then refrigerating the levain for 2 days too, to increase the Labs to yeast ratio in the levain.  Then building the dough and allowing it to retard in the fridge for a 40 hours to also increase the lab to yeast ratio.  Then doing the final proof at 85 F for the same reason.  You can't do this with high % whole grain breads - at least I haven't been able too but you can do the same thing for much less time on the retards - about half as a rule of thumb but even that might be stretching it for some flour combinations.

Going the other way from  SD to yeast is easier.  You can build a biga or poolish out of the flour and water used in the levain or just add yeast to the total flour and water in the dough and levain and be done with it.

It depends on what way I want to go with the SD conversion  More sour larger levain as a % of total.  Less starter for a given % of total in the levain - means more time  or way more starter for a given % of total.  Retard of levain and dough means more sour too.  Flour types make a huge difference.  Breads with high % of whole grains like rye and spelt just won't take a 40 hour retard but the starter can if a stiff one at 60-65% hydration.  As a general rule, the higher the whole grains the less time you have to work with, less levain needed and  lower temperatures you need - if you want sour. 

Depending on what I am trying to achieve,  the ranges I use are 5% up to 50% of the dough total weight can be levain.  It can be retarded or not.  From 1g to 50 g of SD seed can be used.   It can be used at its peak or after retarding a couple of days for more sour.   Retard times can be zero to 40 hours depending on sour wanted and final proof temps can be 36 F to 85 F - baked right of the fridge if using 36 f final proof.  It all depends how much time you want to spend, your baking schedule, how much sour you want to end up with and the size of the bake - something left out of this post since I usually only bake 1 or 2 loaves at a time.

Some recipes call for a booster of commercial yeast to a SD bread.  I use YW for that and it too has the same kind of variables the SD does - plus there are all kinds of non sourbreads you can make with it.  It's just another bread variable from my point of view.

I think all of these variables are the reason you don't see a one spreadsheet fits all for conversions.  Oddly, all the old SD breads had to be converted to commercial yeast once it was invented and we now are converting them back again.  There must be a billion combinations to make just the bread you want - if you can find it and plenty of experimentation needed :-)

That's what I do and hope it helps you .   Others might disagree about any and all of this but that is my experience and what this site is all about.  Learning through discussion and sharing.  I sure have learned a lot at TFL from others sharing what they have learned.  Inspiring really.

Happy baking.