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### Author Topic: Volume vs Fermentation  (Read 398 times)

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#### Jersey Pie Boy

• Posts: 5454
• Location: Portland, Oregon
##### Volume vs Fermentation
« on: July 11, 2019, 06:51:50 AM »
Hi Tom,

I have noticed this for a while but realize I don't quite understand it.

If I use tiny percentages of IDY, I see a  smaller volume of  the fully fermented dough  in the container compared to higher amounts of yeast  I'm thinking less yeast equals less rise..is this correct? And how does that affect the baked pizza?

With SD doughs , the smaller volume doesn't seem to apply..is that right? And why?

Thanks

#### The Dough Doctor

• Tom Lehmann
• Moderator
• Posts: 5856
• Location: Manhattan, KS
##### Re: Volume vs Fermentation
« Reply #1 on: July 11, 2019, 12:01:43 PM »
JPB;
It's simple math, each yeast call metabolizes sugars during the process which we call "fermentation" as a byproduct each cell produces acids, alcohol, and carbon dioxide plus a small amount of heat resulting from the heat of metabolism. It is primarily the carbon dioxide that is responsible for the increase in volume/decrease in density of the dough during the fermentation period so the more yeast cells you have doing this the more carbon dioxide is being produced within any given period of time and the dough becomes greater in volume. Because commercial yeast is somewhat standardized, meaning if you add "X" amount of yeast, within a given period of time you will get a specific amount of fermentation taking place and if you add "2X" amount of yeast you will (with fairly good predictability) get twice the amount of fermentation taking place (assuming there is sufficient nutrient to feed all of the yeast). With a sourdough you have a bacterial culture which can exhibit a different growth rate than yeast and add to that you have no idea of the concentration so it's no wonder that you will see a different change in dough volume, you're sorta comparing apples and watermelons from a microbiology point of view.
All things equal, less yeast means less fermentation (less effects of fermentation on the dough and flour) so a dough made with less yeast will show more signs of under fermentation than a dough made with more yeast at any given point of time. This is not to say that doughs made with smaller yeast levels will always show signs of under fermentation, they will just need more time to ferment the dough to the same magnitude that a greater yeast level did in a shorter time. The characteristics of the finished crust will reflect the amount of fermentation the dough received.
Tom Lehmann/The Dough Doctor

#### Jersey Pie Boy

• Posts: 5454
• Location: Portland, Oregon
##### Re: Volume vs Fermentation
« Reply #2 on: July 11, 2019, 03:21:24 PM »
Thanks Tom...so these five day dough balls may receive proper fermentation ,  though with less CO2, still less volume, if I understand correctly?

#### The Dough Doctor

• Tom Lehmann
• Moderator
• Posts: 5856
• Location: Manhattan, KS
##### Re: Volume vs Fermentation
« Reply #3 on: July 11, 2019, 06:13:52 PM »
No, it just takes more time to achieve the same level of fermentation when using a smaller amount of yeast. This is why we use a higher yeast percentage when making a no-time/emergency dough than we do when making a 5-day cold fermented dough.
Tom Lehmann/The Dough Doctor

#### Jersey Pie Boy

• Posts: 5454
• Location: Portland, Oregon
##### Re: Volume vs Fermentation
« Reply #4 on: July 11, 2019, 08:48:41 PM »
My life would be so much simpler if I had an actual brain, to wit:

So...if my low IDY, long-fermented dough  isn't achieving the same volume as the shorter, higher IDY dough, something is amiss?  (PS) a poolish is part of the equation here if that changes the picture at all. A common formula might be a 40% of total flour poolish, with IDY at 2%  of total formula flour...and that would often be the only IDY in the mix, so not a lot of boost happening...but the oven spring and the flavor is usually very good, Of course, key word there is

So Im testing some dough with this same percentage right now, after going almost 24hrs at RT 64-68. then into cold fridge to hold...We'll see how this works, wuith the thought that sometimes my dough isn't getting enough of a head start with fermentaion early on, snd  that it may not thrive.

Thanks Tom!

A D V E R T I S E M E N T

• Posts: 5654
• Age: 60
• Location: St. Joseph, MI
##### Re: Volume vs Fermentation
« Reply #5 on: July 11, 2019, 09:53:48 PM »
Bill, 2% IDY seems extremely high for anything you have shown us, especially when you say “...so not a lot of boost happening...” Is that what you meant?
-Tony

#### The Dough Doctor

• Tom Lehmann
• Moderator
• Posts: 5856
• Location: Manhattan, KS
##### Re: Volume vs Fermentation
« Reply #6 on: July 11, 2019, 10:06:06 PM »
2% IDY with extended room temperature fermentation time would be considered outrageous. That amount of yeast would probably metabolize all available sugar in 6 to 10-hours.
Tom Lehmann/The Dough Doctor