The Fresh Loaf

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How much commercial yeast to add to the final dough when using pre-ferments?

Andresito's picture
Andresito

How much commercial yeast to add to the final dough when using pre-ferments?

Hi to everybody,

I was wondering...

How much commercial yeast (if any) do I need to add to the final dough when using pre-ferments?

Let´s say I want to bake a recipe that calls for a poolish or a biga.

The questions are:

1. Do I also need to add commercial yeast to the final dough? (notice that I´m talking about adding commercial yeast to the final dough, not the poolish or biga themselves, which they already have a tiny bit of commercial yeast)

2. Will the dough leaven properly just by the action of the poolish or the biga? (maybe it´s not neccesary to add additional commercial yeast to the final dough?)

3. If it´s not necessary to add commercial yeast to the final dough when using a poolish or a biga, What would happen if I actually add more commercial yeast to the final dough?

4. Is there any ratio I should use when trying to calculate the amount of commercial yeast to add to the final dough? (assuming of course, that I´m also adding a poolish or a biga to the final dough)

 

Let´s take the following example:

 

My final dough (without using pre-ferments):

flour = 165 g

water = 105 g

commercial yeast = 10 g

 

My poolish:

flour = 15 g

water = 15 g

commercial yeat = 0,01 g

 

My final dough (using the poolish):

flour = 150 g + 15 g = 165 g

water = 90 g + 15 g = 105 g

commercial yeast = X + 0,01 g = Y

 

What should be the value of X?

In other words, how much commercial yeast should I add (if any) to the final dough? (in addition to the 0,01 g of commercial yeast that it´s already contained inside the poolish)

I hope someone can enlighten me about this issue.

Thanks in advanced!

 

 

 

tgrayson's picture
tgrayson

Ultimately it depends on how fast you want the final dough to ferment. It will be affected by how long long your poolish fermented and what percentage it forms of the final dough.

When making sourdough, for instance, the preferments contain all the yeast that your final dough will ever have.

You don't have to add any commercial yeast when using a preferment, but the final dough will probably take a long, long time to rise. Every recipe I've seen adds quite a bit more yeast in the final mixing.

Now, looking at the numbers you provide, you're using a huge amount of yeast and your poolish is a very small percentage of your final dough. If your non-poolish dough is 165 g, I wouldn't use more than 1.6 g of yeast, with 3.2 g maximum.

Andresito's picture
Andresito

Thanks for your insight tgrayson,

The poolish ferments for 18 hours.

You say I'm using a huge amount of yeast, so would you say that I shouldn´t use more than 2% of yeast in relation to the total flour weigth? (this case 165 g)

You also say that the poolish is too small percentage of the final dough. The poolish is around 9% of the total flour weigth (165 g).

Is 9% too small? what percentage should I use then?

I want to clarify that the dough is for making pizza and not bread, maybe this can justify the small percentage of the poolish? 

tgrayson's picture
tgrayson

2% is in the range of "ordinary bread"; those shooting for maximum flavor often use less in order to increase the fermentation time. Again, depends on what your goal is. A highly enriched dough might need a bit more power to rise and long fermentation may not help too much when the other flavor components dominate.

I didn't actually say the poolish is "too small", I just said "small". Just pulling a book off at random on my shelf, Amy's Bread has a poolish quantity that's almost 50% (Baker's percentage) in her baguette recipe.

I don't have a recommendation for pizza dough; you need to test the flavor of each variation yourself. Rather than using a poolish, though, you might just put the final dough in the refrigerator for a day or two.

 

Andresito's picture
Andresito

Thanks for your input tgrayson,

When you say " Rather than using a poolish, though, you might just put the final dough in the refrigerator for a day or two."

It makes me wonder, what happens if I put a dough with poolish in the refrigerator for a day or two?

If I use a poolish on the final dough, am I not suppose to put it in the refrigerator?

tgrayson's picture
tgrayson

You can put a dough with some other preferment in the fridge; I do that all the time.

Lazy Loafer's picture
Lazy Loafer

I make a couple of different breads with a pre-ferment. One of them uses around an 1/8th of a teaspoon of yeast per loaf in both the poolish and then in the final dough, the other uses a small amount of yeast in the biga starter and a larger amount in the final dough. In the first case, I mix the dough in the evening and let it sit for a couple of hours at room temperature, then it goes in the fridge to bulk ferment overnight. I actually forgot to add the bit of yeast to the final dough for this bread once and it turned out just fine; apparently the length of the ferment allowed the tiny amount of yeast in the poolish to populate the dough. The second kind of bread (with the biga) doesn't have this long ferment time (the biga ferments at room temperature overnight but the final dough doesn't have a long bulk ferment). And also, for this second dough, a large percentage of the flour is in the pre-ferment.

So I guess the answer, as always, is "it depends"! :)

Andresito's picture
Andresito

Thanks for your contribution Lazy Loafer!

From what I´ve read so far it seems it depends on the fermentation time of the dough.

Do you know any relationship between the fermentation time vs the amount of yeast to use.

It will be good to have a table which indicates the amount of yeast in relation to the fermantation time of the dough.

Something like this:

Fermentation time                  Amount of yeast

2 hours                                          X g

5 hours                                           Y g

8 hours                                           Z g

Overnight                                       P g

mwilson's picture
mwilson

0.1% per 16-20 hours
1% per 7-9 hours
2% per 3-5 hours

Fresh / cake yeast (instant, divide by 3). Fermentation temp = 21C.

Above all else the poolish must be exposed to the air!

source: http://www.pizzaioliingiroperilmondo.com/ricette-e-info/il-poolish/

tgrayson's picture
tgrayson

I use an air tight container for poolish all the time. Works fine.

mwilson's picture
mwilson

It may work fine..

However to echo the writings of the masters when trapping CO2 you slow the development of acidity.

perhaps you'll see an improvement if you heed their advice...

tgrayson's picture
tgrayson

Well, I have only your say-so that this is true. And even "masters" sometimes pass along old wives tales because they never saw fit to actually test them.

But regardless, it's not an "above all else" sort of issue.

mwilson's picture
mwilson

I see your predicament. But Italian bakers of notation are scholared and adhere to scientific and technical knowledge. I have read much and this consideration for environmental conditions is repeated often. It is the whole basis for biding lievito madre to delay acidification.

"above all else" echo's their sentiment!

Perhaps you should read the linked article. It may settle your turmoil. 

rgconner's picture
rgconner

Co2 mixes with water to make carbonic acid.

So exactly how would trapping the CO2 prevent acidity?

Now, if you said I needed to leave it open to ensure a flow of oxygen to encourage the growth of acid producing bacteria I would buy that.

But we are talking commercial yeast only here, and that does not require oxygen to ferment. (or wine would not ferment in sealed bottles)

mwilson's picture
mwilson

Makes no scientific sense! How so??? Do explain...

Both aspects hold true.

By trapping CO2 the area surrounding the dough or batter is dilute of oxygen an important factor as you point out.

More relevantly the technique of binding employed with the maintenance of lievito madre will trap CO2. Carbonic acid is acidic and under pressure even more so. Lactic acid bacteria are pH sensitive. Acidification is delayed with the accumilation of CO2 due to pH.

Yeast doesn't require oxygen in the short term but it's vitality does depend on it. Secondary fermentation in the bottle happens if there is residual sugar available and if the alcohol content isn't already too high.

Ultimately CO2 like other metabolites, like acids serve to slow fermentation.

rgconner's picture
rgconner

Yeast does not need oxygen, long or short term. It can do it's job in a totally anaerobic environment. 

There are NO BACTERIA in commercial yeast! So no oxygen is needed. No Lactic Acid Bacteria means no Oxygen needed to feed them.

"Acidification is delayed with the accumilation of CO2 due to pH."

"Ultimately CO2 like other metabolites, like acids serve to slow fermentation."

Isn't acidification what we are trying to achieve? You said trapping the CO2 would slow acidification, now you are saying the opposite. 

CO2 does not increase PH, it lowers PH, which is what we call ACIDIC. MORE C02 means MORE ACID.

Which is what we want to do! 

 

mwilson's picture
mwilson

I've confused you and I've drifted outside the topic at hand to make clarity on my point. However you don't understand.

The growth of yeast is greatly limited without oxygen.

The acidification of dough is due to the development of lactic acid bacteria. Stating "there are no bacteria" is wrong and short sighted.

LAB will develop in commercially yeasted preferments especially if the maturation is long. LAB drive the lowering of pH.

Acidification due to CO2 is temporary.

Carbonic acid is acidic I never said it increases of pH. I'm not sure how you got that, you must be tired.

 

rgconner's picture
rgconner

Yeast do not need oxygen!

 

http://www.the-scientist.com/?articles.view/articleNo/31027/title/Yeast-Don-t-Need-Oxygen/

 

You said right here:

"Acidification is delayed with the accumilation of CO2 due to pH."

Since CO2 lowers PH, the only way CO2 could delay it is if it RAISES pH.

Which it does not.

I am not the one that is tired if you think that your claim of C02 and pH makes any sense. CO2 accumulation will not delay acidification because it is an ACID when dissolved in the dough, or it makes no difference if it is not. 

"Stating "there are no bacteria" is wrong and short sighted."

There is NO BACTERIA in COMMERCIAL YEAST. 

Which is what I said. I did not say there were NO bacteria. 

Sure, there are some in the dough, but seeing how it takes at least a week to get them going in a home grown sourdough, I cannot imagine any case where a day or two would make any difference.

Most start from scratch starters don't start bubbling till the 2nd or 3rd feeding. So how does a 12 or 24hr establish any significant population of wild bacteria?

mwilson's picture
mwilson

Interestingly titled article given each successive mention on the subject admits the opposite.

Acidification by LAB. Thant's what you are missing. With the biding of lievito madre, forcing the dough to mature in an enclosed space saturates levels of CO2 decreasing the pH quicker than would happen normally. Which means the LAB shut down quicker, delaying the production of acids by them, ie, lactic and acetic. Make sense now?

This is a little off-topic. But I'm explaining it to highlight how trapping CO2 creates a different fermentation..

In commercial yeast? Well in fresh there most definitely is. Regardless the point is LAB play a significant role.

LAB in commercial yeast preferments will achieve levels equal to that of SD in 24 hours. Yeast act as a catalyst.

Andresito's picture
Andresito

Hi mwilson!!

Thank you for this table!

It will be of great utility :)

Just allow us to clarify some points:

1. This table of yeast vs ferementation time is for the poolish or the final dough? or both?

2. The percentages are based on the total flour weigth of the final dough? Or the total flour weigth of the poolish?

3. If the table is for the poolish, Is there a similar table for the final dough?

mwilson's picture
mwilson

1. just the poolish

2. flour weight for the poolish

3. Not in this case. The article linked details instructions specifically for the poolish pre-ferment.

Andresito's picture
Andresito

I understand mwilson, Thanks!

However, regarding point number 3

Isn´t it logical to assume that the table will also work for the final dough?

At the very end, the poolish is just flour, water and yeast (and the yeast is a % of the flour)

If we make an analogy, the final dough is flour, water and poolish (the poolish acts like the yeast now and it´s also a % of the flour)

For instance, let´s take my example:

poolish

flour = 15 g

water = 15 g

yeast = 0,01 g (0,06% of 15 g)

fermentation time = from 18 to 24 hours

 

Final dough

flour = 150 + 15 = 165 g

water = 90 + 15 = 105 g

poolish = 15 + 15 + 0,01 = 30,01 g (10% of 150 g)

fermentation time = 1 hour?

It would be something like this

Or maybe not?

mwilson's picture
mwilson

Different methodologies.

With the poolish one is seeking to maximise fermentation to ultimately enhance the end product with respect to flavour, texture and shelf life.

With the main dough, getting it leavened properly, ie, time of bulk and proofing is the important factor.

Andresito's picture
Andresito

I see...

Let me see if I get this rigth.

Let´s assume that I already have a poolish or a starter that achieved the maximum fermentation point (to provide the flavour, texture, etc)

At this point, flavour is not the main goal (because that it will be taken care of by the poolish). The main goal now is to leaven the final dough properly.

So the fermentation of the final dough IS NOT with the purpose of achieving flavour. The fermentation of the final dough IS JUST to leaven it properly.

Is that it?

Bulk and proofing have anything to do with flavour and texture?

barryvabeach's picture
barryvabeach

When you are making bread, in general, bulk fermenting is for flavor, both bulk and proofing impact texture. Most dramatically, if you over proof, your bread will collapse. 

mwilson's picture
mwilson

That's about it.

Throughout the entire process fermentation is underway. Flavours are being created all the time. The longer the process, the greater the potential to make better bread.

In this case of using a pre-ferment you offset the fermentation to a portion of the flour. Working this way, the indirect method provides you with greater options. Add to that different pre-ferments provide different results. For example, wet starters like a poolish help to improve extensibility and firm ones like a biga help to boost strength. Both improve flavour.

Bulk fermentation is ultimately for one thing and that is to develop strength, so that when you form the dough it holds it's shape.

Proofing allows you raise the dough to a point where maximum volume can be realised via the bake.

Andresito's picture
Andresito

Can someone else shed more ligth on the problem?

barryvabeach's picture
barryvabeach

Andresito,  actually, you said you were making pizza dough, and while the ingredients and some of the steps are the same, some are different. In bread, we normally bulk ferment until doubled ( in some cases tripled is size) , then divide and shape , then final proof and then into the oven at some point before it is 100% proofed.   It is not uncommon to use preferments for pizza dough, but more commonly the dough is mixed with yeast, or a natural starter, and is left in a bulk ferment - usually at a cooler temperature for a long time.   Some leave it as a bulk ferment until it is taken out from the cooler, usually an hour or so before shaping, it is then shaped and then cooked.  In some cases, the dough is reballed while in the cooler, though that is similar to a stretch and fold to develop gluten, and perhaps redistribute yeast, but it is not very common that one waits till it is doubled in size before reballing, and in either case, it is removed from the fridge not as some percentage of proofing, but instead at a time when flavor is maximized.   Since you are interested in pizza, here is a link to some experiments on bulk ferment, and reballing. http://www.pizzamaking.com/forum/index.php?topic=16618.0  BTW,  you can spend years reading different recipes, approaches, and different types of pizza, this thread is on New York Style.   

Andresito's picture
Andresito

Thanks for you contribution barryvabeach!!

Interesting post and interesting forum!!