Author Topic: The Nature of the Yeast  (Read 9551 times)

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Offline varasano

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Re: The Nature of the Yeast
« Reply #20 on: October 05, 2006, 04:15:46 AM »
Pizza, Bread, Cake, Souffle, Popovers...

Let me clarify some of the logic on this whole issue of whether spring is caused by steam vs. yeast continuing to eat. This has been referenced on several threads and I'm really addressing all of these threads here. Pete, as I've said before, the bread making guys are looking for an explanation that fits what they are doing and they found it with the yeast rise theory.  A 45 minute bread bake leaves their bread yeast in the warm zone for a good 20 minutes so there's enough time to do some real metabolic activity and create some CO2 based rise.

Some of these pizzas are cooking in 1 minute, leaving the yeast in the warm zone for all of 30 seconds and there's just no time for any real eating or metabolic activity to occur.

Yeast is not necessary for foods to rise. Souffles & Popovers have no yeast at all. Trapped Steam is the primary leavening agent in their rise.

A tiny amount of water, turned to water vapor, is a huge volume. At standard temperature and pressure 1 gram of water has a volume of 1 cc. Converted to vapor the volume is 22,414cc (Mole volume) / 18 (molecular weight of H20 = 1+1+16) = 1245 cc. Now account for the temp difference.  The baking institute says rise stops at 153. That is 340 Kelvin which is 24.6% higher than standard temperature and pressure (273 Kelvin). So 1245cc*(340/273) = 1551 cc. So one gram of water is equal to over a liter and a half of water vapor at 153F.

Someone on another thread complained that steam could not be the answer because the dough did not reach boiling temp therefore there was no steam. This is faulty logic. Water does not begin to turn to water vapor at the boiling point. Water will turn to water vapor at any temperature. Even ice evaporates.

What causes water to convert to water vapor and at what temperature?

Water molecules on a surface have varying temperatures. Temperature is a measure of AVERAGE velocity of the atoms. At any given moment, almost all molecules are either above or below that average. The temp is like the peak of a bell curve. Few molecules are exactly on the peak line, they are all over the curve. Pool balls make a good analogy.  During a break the average velocity of the balls is high, but at any moment, if you looked, some balls are almost stopped and others are moving very fast. An individual surface molecule evaporates when, during the pool-table like jostling, it happens to get up enough speed to pass a threshold - It's moving so fast that it can break away from some electric forces which are holding it to the other water molecules. In other words, the items at the top of the bell curve escape.  This lowers the average temperature of the remaining molecules - they keep losing their best players. This is why water is always colder than the surrounding area. Oil, which does not evaporate, does not feel cold on your skin. Here's an example: you have 10 molecules with an average speed of 50 - a total momentum of 10x50 = 500 . But this energy is not distrubuted evenly. As molecules bang in to each other the transfer the energy around from one to another. The total remains the same, bu the distribution is always changing. Let's say that one has a speed of 200 and the remaning 9 split up the remaining 300 units of momentum. If the fast one is moving inwards towards the others, it will hit one of them and slow down. But if it's moving out from a surface, it will have enough speed to break away. So let's say that the 200 molecule breaks out. Now you have 9 remaining molecules with a total momentum of just 300, so they average just 33 per molecule. They are now colder, by definition.  Get it? 

Continuing our example, the escapee pushes off the other 9 at a speed of 200. This means that the water is exerting an outward pressure. Molecules are literally jumping ship, pushing out. This is 'vapor pressure'. It occurs at all temperatures. It does not start at 212. If it did, then room temp water would not evaporate or feel cold on your skin. Even ice evaporates and has vapor pressure. The pressure is the sum of the momentum of all of the escapees. Air also has pressure. At sea level Air has a pressure of something like 760 millibars of mercury. If you had a pool of mercury, (a heavy liquid metal), and it was 760 millimeters deep, it would push down on the bottom of the pool with a certain amount of force. It's heavy. Regular air at sea level exerts the same amount of force. It's the heavy weight of all the air up to the top of the atmosphere pushing down.  Water at room temp exerts wapor pressure. But at room temp the pressue something like 22 millibars.  So the peak of the temp bell curve is so low then only a few molecules all the way to the right of the curve are energetic enough to escape. Evaporation is slow. But as the sample rises in temp, the whole bell curve moves over and more and more of the right side of the curve is over the threshold. As the more vertical part of the curve moves over the threshold, small increases in temp result in larger and larger increases in vapor pressure. At 212, the vapor pressure is 760. This is the boiling point because now the vapor pressure is more than the air pressue and a majority of molecules have enough energy to escape. The water stops rising in temp at that point because as energy is pumped in, water molecules use it to escape, leaving the cool ones behind, until they've all escaped.

The point is that the increase in pressure does not begin at the boiling point of 212. Rather, the pressure rises along a curve up to that point. At lower pressures (higher elevations) the boiling point is lower because the threshold is not 760 mb but lower.

Only 1 gram of water turning to vapor is over a liter and a half in a risen dough. This is plenty of volume to account for the rise of the dough.

As I said on my site, yeast is needed to start the bubbles. The yeast creates what amounts to a foam - a body with lots of small air pockets and LOTS of surface area.  This surface area is where the water evaporates into. Water in a cup evaporates slowly. Spread on the counter, it evaportates quickly. Both samples are at room temp. The water in the cup evaporates slowly because the energetic molecules in the center bump into other molecules in the center, transfer their energy and don't escape. Only molecules at the surface escape. The water spread on the counter has lots of surface area. The vapor pressure is the same because pressure is measured per area of surface. But the amount of surface is greater, so the amount of evaporation is greater. Risen dough is essentially a foam. It has lots and lots and lots of surface area, mostly on the inside. It's like your lungs. Look how much water vapor comes out of your lungs with each and every breath. The volume of air you exhale is greater than the volume of air you inhale, because the air you exhale has more water vapor in it. The lungs have a huge surface area inside, just like the dough. Dough without yeast would have no bubbles inside. It would heat like the cup of water. Only the surface would evaporate. Interior molecules would simply bump into other molecules an not evaporate. As it heated, it would eventually heat enough that the vapor would press out and create escape routes, but it would not be anything like the even expansion that you would see in an airy foam.

A souffle is a similar type of foam with beaten egg whites forming a foam of air and proteins. Both Souffle's and popovers are good examples of steam-only rises. No CO2 gas producing leavening agent such as yeast or baking powder is needed. Only steam and a protein is needed.  Unlike breads, souffle's have no geletanized starches to hold their shape so they are fragile and fall when cooled because the vapor pressure stops. Popovers, sit somewhere in the middle. They have starch, but since popovers do not have the benefit of being foamed before their rise, the distribution of the expanding gas is not spreadout through the batter. Instead the expansion simply occurs in a few large pockets. No latticework of geletanized starches is created. Therefore when cooled and the vapor pressure is reduce, popovers will also collapse. This is why it is best to poke the popover before it cools, to let the steam out before it condenses (condensation reverses the evaporative pressure).

Beating the hell out of a dough is like disturbing a souffle or popover. You are breaking the structure - weakening it's ability to capture whatever gas is trying to expand it. The amount of gas produced might be similar, but the structure will not hold it in the same way. November is correct about overrisen dough. In fact overrisen dough has plenty of live yeast in it. If you culture it, you will see that. But overrised dough has weakened it's gluten structure in at least two ways.  It may have expanded too much creating thin and fragile bubble walls, and it has chemically broken down some of the gluten by producing too much acid. When the steam is created during baking, it just leaks out.

Look at the video that someone posted (I think it was Bill) of the brick oven bake. There's a bubble that you can actually see expanding. Most of the expansion is done in under a minute. This is a straight physical process.
« Last Edit: October 05, 2006, 04:19:22 AM by varasano »


Offline November

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Re: The Nature of the Yeast
« Reply #21 on: October 05, 2006, 04:53:31 AM »
And to add to varasano's very descriptive and 99% correct post, you can read more about protein stability here where every mechanism under the sun that either denatures or destabilizes protein is described:

http://employees.csbsju.edu/hjakubowski/classes/ch331/protstructure/olhydrophobprot.html

varasano, the missing 1% (which would probably go over most people's heads anyway) is the consideration for gas pressure within the dough that has an accountable, albeit sometimes negligible, effect on the water's heat of vaporization.  As the pressure rises within the dough, the temperature required to evaporate also increases.  Again, this is usually negligible, but I figured I would mention it as long as you were going overboard with your explanation.

Offline shango

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Re: The Nature of the Yeast
« Reply #22 on: October 05, 2006, 08:12:04 AM »
well, comparing pizza and biscuits is like comparing  :angel:s and  >:Ds.  I make somewhere between 400 and 600 pizze in a day and I can say that in the case of making a good pizza it is absolutely essential that the yeast is alive at the time of baking. 

Unless you are making biscuit pizza I guess.
pizza, pizza, pizza

Offline Pete-zza

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Re: The Nature of the Yeast
« Reply #23 on: October 05, 2006, 08:18:13 AM »
Jeff and November,

Thank you both for your contributions on this point.

I'd like to ask either or both of you what the practical takeaways are for the average home pizza maker, particularly those using standard home ovens, which represents a large percent of our members. For example, when I have used large amounts of yeast, I found that I did get greater oven spring but, like Jeff, I have also been able to use almost minuscule amounts of yeast and achieve good oven spring. Is there such a thing as using too much yeast from an oven spring perspective or will the excess just die off when the dough temperature gets high enough?

High hydration is often credited with producing greater oven spring but is there a practical limit or range beyond which it is not a good idea to go? In other words, is it possible for a dough to become too "waterlogged" to produce a good oven spring, assuming that one is able to actually handle and shape the dough into a skin and be able to load it into the oven? Finally, is it a good/bad idea to be rough with the dough and press out the gases at the time of shaping by slapping it around as many videos of professional pizza makers show? I have seen this done many times and yet the pizza crust had good oven spring. In most cases, a very high temperature oven was being used, and I wonder whether the very high oven temperatures were a major factor. Or whether something happened earlier with the dough to make this possible.

Peter

Offline Pete-zza

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Re: The Nature of the Yeast
« Reply #24 on: October 05, 2006, 09:01:31 AM »
The purpose of the refrigerated rise is to allow the dough to form glutens (elasticity) for a good stretch and a nice smooth texture.  It also allows the dough to develop a softer mouth feel and a better flavor.


Edan,

The reason I asked the question about cold fermentation is because of an exchange I had some time ago with pizzanapoletana (Marco) at http://www.pizzamaking.com/forum/index.php/topic,1298.msg13410.html#msg13410 (Reply 125). I know that under the tenure of the former chef at A16, Christophe Halle, cold fermentation of the dough was also used at A16. Given a chance, I would have asked the same question of Chef Halle.

Peter

Offline varasano

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Re: The Nature of the Yeast
« Reply #25 on: October 05, 2006, 09:51:37 AM »
Edan,

You are coming into a long running academic debate spanning several threads - I don't want you to think that I'm recommending baking dead dough or something.

Pete,

The more I look at this issue the more I want to go back to the drawing board. In some of my lectures I give a talk on the concept of mastery. Mastery is a two steps forward one step back process. But every once in a while when mastering a skill it's good to rip up your whole procedure and try somethings way outside your norm. This is one of those times for me. The procedure on my site definitely works extremely well. I think that I've had so many bad pizzas and I've seen 100 ways it could go wrong, that it's easy to conclude that some methods don't work and then they get abandoned. I've been looking for one solid cohesive plan. But perhaps there are also 100 ways to do this right that may differ wildly. This whole topic has me wanting to run more experiments rather than giving advice. Logically, a super wet, dough would produce lots of gas and a super well kneaded, highly windowpaned dough would capture that gas best. I've assumed that for a long time. Yet that is not my current procedure, which works well. I don't mix to the highly windowpaned stage.  This is the area that I want to play with. Large amounts so of pre-bake rise doesn't seem to work well with lightly mixed doughs. But perhaps if I kneaded more, then things like highly risen dough and punched down, re-risen dough and more yeast become viable options.

So take the rest of this as my current thinking, but I might rip it up soon:

> when I have used large amounts of yeast, I found that I did get greater oven spring
I personally have not found that. I think that small amounts of yeast can produce as much dough rise as large amounts, just slower. I don't think that the starting amount is as important as the overall amount of pre-bake rise. Obviously, I think we've all concluded that small amounts and slow rise are better for flavor. To me the question is how much dough rise is the right amount, rather than how much starting yeast is the right amount.

However, I'm really open to anything after seeing some of scott r's photos that he posted recently. These showed excellent spring using a cool oven (550) and incorporating a triple rise, punch down and another triple rise. Those photos really surprised me. They definitely showed me that there is more than one way to skin this particular cat. They are the opposite of what I do which is a single 50% rise, and a hot oven (825F).

Scott, could you address the exact procedure you used for those. Did you mix really really well, all the way to a very fine windowpane? Even though I show some highly windowpaned examples on my site, I typically do a much lighter mix and consequently I have found that too much dough rise weakens the structure. I get an excellent spring with my procedure. But if I were to manhandle the dough, I think it wouldn't work. Perhaps with more kneading to the fine windowpane stage, it could take more rise and more handling. The one time that I did handle an uncooked Patsy's dough it was unbelievably windowpaned, unlike anything I've ever tried to produce. I know that sounds strange since I'm on this Patsy's quest, but I've just not gotten around to that particular experiment in the zillions of other things I've tried in my limited time. I really want to make a single batch that I pull balls out of the mixer at 5, 10, 15, 20 and even 25 minutes and see how they compare.

>is it a good/bad idea to be rough with the dough and press out the gases at the time of shaping by slapping it around as many videos of professional pizza makers show? I have seen this done many times and yet the pizza crust had good oven spring.
I've seen this rough handling, like the baroanda video posted yesterday. But I've seen these pizzas come out flat. You do not want to eat the baroanda pizza, I promise. That was all show. I would think that to stand up to that treatment the dough would have to be extremely well developed - highly kneaded.

>High hydration is often credited with producing greater oven spring but is there a practical limit or range beyond which it is not a good idea to go? In other words, is it possible for a dough to become too "waterlogged" to produce a good oven spring, assuming that one is able to actually handle and shape the dough into a skin and be able to load it into the oven?

Marco posted a focaccia with an 85% hydration that had lots of big bubbles. Popovers are made with a batter.  So I'm not sure that the dough can be too water logged. I just saw a video a few minutes ago of the guy from Pepe's in New Haven spreading his dough. It looked super wet to me. He couldn't even really pick it up. He just put it on the counter and pushed it and it spread out. But then he bakes a 10 minute pie, so it still didn't have much spring.

If spring were the only consideration, I'd guess that very, very wet, and very very well kneaded would give the most spring. Having said this, spring is not the only consideration and I'm not sure that this procedure would be the best pizza. 

I'm going to run some more tests...

Offline November

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Re: The Nature of the Yeast
« Reply #26 on: October 05, 2006, 12:45:23 PM »
I make somewhere between 400 and 600 pizze in a day and I can say that in the case of making a good pizza it is absolutely essential that the yeast is alive at the time of baking. 

I used to make hundreds of pizzas a day many years ago, and I can say that it's not absolutely essential.  In fact, regardless of how many pizzas either of us have made, we're talking about the constituent actions leading to dough rising in the oven, which is not like comparing angels and devils.  Whether it's by chemical reaction, metabolic process, or politicians billowing air, it's all still an observation of the same function: oven rise (or oven spring as some would call it).  Now if we we're talking about flavor, of course the comparison would be different.  However, even in that case, I doubt that having yeast alive when placing the pizza in the oven will make any difference since they die a quick death before you taste it anyway.  Flavor, as it relates to yeast, should be expressed as a function of yeast amount * available nutrition * metabolic rate * time.  Generally, the difference between the highly objective "good vs. bad" tasting crust is found between two points on a nonlinear scale.  It's not as easy as, "the yeast must be alive when in the oven."

Which leads me into my response for Peter.  I've pointed to several factors before that have relevance to your quandary.  At some point I may have to resort to a "grand metaphor" to explain the day in the life of yeast and how it relates to pizza crust, but for now I'll try to keep it as short as possible.  Yeast are much like any other living organism, they need food, water, and trace minerals for cellular respiration to occur.  They're also fond of space and nitrogen containing compounds for reproduction and colonization.  To make one comparison to farm animals for a moment, yeast are in competition for nutrients just like animals on a farm.  When lots of animals are confined in a small space, they become agitated, nervous, and even frightened.  The reason for this state of being is due to a concern over food supply.  When one animal spends all of its time near other animals, the animal is hardwired for concern over whether it will get the food it needs to survive.  This condition causes health problems for them (and eventually for us) as excess cholesterol is released in the body as a precursor to forming steroids which will provide the animal the aggressiveness to compete for the food.  Yeast act the same way, but with less hardwiring.  That is to say they don't react to stimuli as complex as social interaction, but they do react to their environment.  The more yeast you have within a defined space, the more they will be able to sense nutrient depletion in their surroundings.  When nutrients aren't as readily available due to overpopulation, the yeast react by producing chemicals within to compensate.  It's kind of like with animals that don't get enough protein in their diet, so their digestive system cannibalizes muscle tissue and tract lining.  As a result of nutrient depletion and chemical re-synthesis, the yeast become lethargic and respire at a slower pace.  Both the flavor and the CO2 levels suffer in the end.

Maybe sometime soon I will post a concise formula that can be used to determine the exact amount of yeast byproducts given the amounts of everything added to the dough.

Offline scott r

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Re: The Nature of the Yeast
« Reply #27 on: October 05, 2006, 01:10:17 PM »

However, I'm really open to anything after seeing some of scott r's photos that he posted recently. These showed excellent spring using a cool oven (550) and incorporating a triple rise, punch down and another triple rise. Those photos really surprised me. They definitely showed me that there is more than one way to skin this particular cat. They are the opposite of what I do which is a single 50% rise, and a hot oven (825F).

Scott, could you address the exact procedure you used for those. Did you mix really really well, all the way to a very fine windowpane? Even though I show some highly windowpaned examples on my site, I typically do a much lighter mix and consequently I have found that too much dough rise weakens the structure. I get an excellent spring with my procedure. But if I were to manhandle the dough, I think it wouldn't work. Perhaps with more kneading to the fine windowpane stage, it could take more rise and more handling. The one time that I did handle an uncooked Patsy's dough it was unbelievably windowpaned, unlike anything I've ever tried to produce. I know that sounds strange since I'm on this Patsy's quest, but I've just not gotten around to that particular experiment in the zillions of other things I've tried in my limited time. I really want to make a single batch that I pull balls out of the mixer at 5, 10, 15, 20 and even 25 minutes and see how they compare.


Jeff,  the dough I pictured was actually mixed for a shorter amount of time than the procedure shown (so perfectly and thoroughly) on your site.  I started with about half the flour all the salt and IDY (only) in the mixer and mixed for 1 minute, then did a 10 minute autolyse.  After the rest period I added the oil and the remaining flour over the course of about 5 or 6 minutes. This whole procedure was done at the slowest setting.   I stopped as soon as the doughball formed around the roller.  I would actally say that it was about half the kneading that you have outlined on your site, and the minimum amount that I could really do and make a decent doughball without chunks in it.

There are a few things to consider that may have helped to create my huge voids even though the dough was lightly mixed, baked at 550, and was fermented to the point of almost being dead.

1 The dough had quite a bit of oil in it. Probably more than usual. That could help to seal in the gasses right?
2 The dough was really wet, At the time I was attributing it to the extra long fermentation, but I do remember it being very very gelatinous when I shaped it and went to shake it off the peel.
3 Light mixing, as shown in a wonderful post of Giotto's a few years back can create very large voids.
4 The sugar in the dough could have helped to feed the yeast, essentially making it so that the yeast didn't know it was overfermented.

Here are my notes from that particular dough so Pete-zza can dissect my recipe and get all analytical on my ass.   ;D   Sorry I didn't measure my flour, but it was very wet.  My guess is that it was at least a 65% hydration, but it could have been higher.

740g water, 30g salt, 20g sugar, 45g oil, 1/4 teaspoon (plus a few pinches) of IDY. dual autolyse (10 at beginning, 20 before 1 minute fold at end) wet dough, light knead, Half General mills full strength flour half KASL flour.  It was a hot summer day, so the dough tripled in 8 hours, spent 24 hours in the fridge, then tripled in volume again before baking.

Jeff, I noticed from my notes that the dough actually spent 24 hrs in the fridge, I think I had originally told you it was only 12.

If anybody feels like trying this recipe I can highly recommend it. I am not norally a big sugar or oil fan, but my goal here was maximum flavor with IDY, and to have a dough that can get crispy even with the wimpiest of ovens, yet still stay soft in the middle.  The recipe was a definite success, so much so that my wife (and main pizza tester) thought it was possibly my best ever normal temp NY style dough.  I have also repeated the recipe with excellent results using 100%  KASL or all KA bread flour.  The oven I used for these pies was very average for 550.  Probably a true 550.  I have found some ovens that cook much slower at 550, and some that seem much hotter at 550.

Offline Pete-zza

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Re: The Nature of the Yeast
« Reply #28 on: October 05, 2006, 01:28:41 PM »
scott, 

Can you provide a link to the Giotto post you mentioned?

Also, how many pizzas do you make from the amount of dough you used, and what size pizzas did you make? And do you remember the dough ball weight? With that data, and assuming a 65% hydration, I think I can come up with the total dough formulation and be able to use the Lehmann dough calculating tool for scaling purposes.

But next time I expect you to weigh the flour ;D.

Peter

Offline scott r

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Re: The Nature of the Yeast
« Reply #29 on: October 05, 2006, 01:45:54 PM »
Peter, I wish I had kept better notes.   I think they were 14 inch pizzas with 330g doughballs, but I could be wrong.  Sometimes I have a little dough left over at the end of making balls that I just throw out.  I made 6 pizzas.

I have been trying to find giotto's post, but I am out of time.    It was a picture of two french breads, once mixed longer than the other.  They were sliced right down the middle so that you could see all the voids, and the lighter mixed dough had larger voids.

Thank you so much for helping Peter.
« Last Edit: October 05, 2006, 01:51:45 PM by scott r »


Offline varasano

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Re: The Nature of the Yeast
« Reply #30 on: October 05, 2006, 02:14:46 PM »
Ok, this was not the answer I was expecting. Now I'm baffled... I'm going to have to read this again when I get more time.

I'm glad the 10 minute autolyse worked. I want to test all the way down to 5 minutes. I really think that is all that is needed, but since I haven't tested it I don't recommend it in my recipe. The problem is that now that everyone knows about my pizza, I always have so many guests and I don't want to disappoint, so I don't run as many tests anymore.

Scott don't throw out that extra piece of dough. Fry it in a 1/8 inch of olive oil, turn to get all sides and dump a spoonful of table sugar on it.

Jeff

Offline Pete-zza

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Re: The Nature of the Yeast
« Reply #31 on: October 05, 2006, 02:18:19 PM »
scott,

I'm pretty sure this is the post: http://www.pizzamaking.com/forum/index.php/topic,524.msg5514.html#msg5514. I specifically remember it because I had brought the progressivebaker website referenced in the above post to giotto's attention. That website had a wonderful course on bread making, and giotto and I frequently referred to it, including some photos that showed different crumb structures, which is what you recalled. Unfortunately, the website was taken down and not replaced by anything else of value. So the progressivebaker link in giotto's post no longer work. Unfortunately, giotto's links don't work anymore either.

Peter

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Re: The Nature of the Yeast
« Reply #32 on: October 05, 2006, 02:26:14 PM »
Re:Quality NY toppings & techniques
« Reply #30 on: August 27, 2004, 07:07:27 PM »

Yes I had this link saved Peter and i'm pretty sure it's the one with three baguettes cut cross section-showing different mix times.
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Offline Pete-zza

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Re: The Nature of the Yeast
« Reply #33 on: October 05, 2006, 02:32:43 PM »
As I noted in an earlier post, a few weeks ago I posed a question to Tom Lehmann on the PMQ Think Tank on the matter of “oven spring”. Apparently he missed my question while he was in Orlando. In light of the recent heightened debate on the matter of oven spring, this morning I sent an email to Tom in which I repeated my original question, as follows:

Can you explain from a technical standpoint, with as much detail as you would like, what "oven spring" is, what specifically causes it, and what factors should be considered to get good oven spring?

Almost immediately I received the following reply:

Oven spring is the increase in volume that the dough undergoes as a result of being put into the oven. Contained within the dough is water and yeast (along with other added ingredients); these are mixed in a dough mixer to develop the gluten from the flour proteins. During this mixing action air is incorporated into the dough to form a matrix of nuclei within the dough. After mixing, the dough is allowed to ferment and/or proof for a period of time; this allows the yeast to activate (begin feeding) and produce byproducts of carbon dioxide, acetic acid, lactic acid and propionic acid (these are the major acids formed). When the dough goes to the oven for baking, the gasses contained within the dough, including the air within the nuclei, begin to expand (Boyles Law) creating pressure within the dough. This pressure causes the dough to expand, creating what we call "oven spring".
 
If this is for a school project I want to know what grade you get on this assignment.


After assuring Tom that I was not worried about school anymore, I followed up with a question on the role of steam vis a vis yeast/carbon dioxide on oven spring. I also copied and pasted Jeff’s long post and November’s follow-up post. I soon received the following reply:

Oven spring is not caused mainly by the carbon dioxide and other volatiles produced by the yeast DURING the oven spring period; instead, the main factors for oven spring are those ALREADY produced by the yeast. The dough has already more than doubled in many cases when it goes to the oven and that increase in size is due to the byproducts of yeast fermentation; now, if you believe in BOYLES LAW (a law of physics and hard to challenge) you must accept the fact that those trapped gasses will expand upon heating and it is this heating and expanding of entrapped gasses, and water vapor (not steam) that contribute to oven spring. The "official" definition of Oven Spring taken from the AIB Glossary of Bakery Terms is as follows:

Oven Spring (oven kick)
The quick rise or expansion of a bakery product caused by the heat of the oven. The heat expands the gasses within the product and also produces a vapor pressure from the moisture within the product, causing the cells in the dough or batter to expand.

There you go. That's the official definition that is recognized by the baking industry.
Tom Lehmann/The Dough Doctor


Whether one agrees with Tom or not, there is no questioning his willingness to share what he knows with others, even those of us who are not professionals. 

Peter

Offline scott r

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Re: The Nature of the Yeast
« Reply #34 on: October 05, 2006, 02:39:58 PM »

Scott don't throw out that extra piece of dough. Fry it in a 1/8 inch of olive oil, turn to get all sides and dump a spoonful of table sugar on it.

Jeff

Problem is, unlike peter I have gained 8 pounds since joining this forum!  Sounds really yummy though!

As a side note, I had rons fried calzone at Il Pizzaiolo and it was better than what I remember of the two fried calzones I had in Naples!  Buffalo Ricotta, wow.

Jeff, This thread is obviously an indicator that we still have a lot of mixing time/methodology research and testing to do.  I make dough just about every day when I am not out of town, and I still have so many experiments to try.  One huge issue keeps popping up in my head.  I still have not been able to make a dough that has seen the fridge with a texture that is as good as my room temp doughs.  I think something happens when the dough gets really cold.  So many mysteries...................  Oh  how I long for the days when Marco was talking.

Offline varasano

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Re: The Nature of the Yeast
« Reply #35 on: October 05, 2006, 02:55:15 PM »
boyles law will expand the gases by about 13-14% (which I account for in my calculations and referenced in another posts where I talked about the relative kelvin temp increase). I'm glad to here that they acknowledged the role of vapor pressure.

Offline varasano

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Re: The Nature of the Yeast
« Reply #36 on: October 05, 2006, 02:57:10 PM »
> I still have not been able to make a dough that has seen the fridge with a texture that is as good as my room temp doughs.

My experience is the opposite. But I know there is a good warm rise technique waiting for me out there. I just don't have the time to make this more than once a week (unless I'm totally procrastinating my real job, like today).

jeff

Offline Pete-zza

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Re: The Nature of the Yeast
« Reply #37 on: October 05, 2006, 03:18:15 PM »
boyles law will expand the gases by about 13-14% (which I account for in my calculations and referenced in another posts where I talked about the relative kelvin temp increase). I'm glad to here that they acknowledged the role of vapor pressure.

Jeff,

I think the use of the term "steam" may have led some people (including Pizza Shark) to think you were referring to it in the common sense as noted, for example, at wikipedia:

In common speech, steam most often refers to the white mist that condenses above boiling water as the hot vapor ("steam" in the first sense) mixes with the cooler air. This mist is made of tiny droplets of liquid water, not gaseous water, so it is no longer technically steam.

Peter

Offline Pete-zza

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Re: The Nature of the Yeast
« Reply #38 on: October 05, 2006, 04:18:31 PM »
scott,

For all the ingredients you gave other than flour, I calculated a weight of about 838 grams. If you made six dough balls weighing 330 grams each, I calculate that the flour component is 1142 grams. With water at 740 grams, the hydration comes to about 65%, just as you said. For the 330-gram dough ball weight and corresponding 14” pizza size, I calculate the thickness factor to be 0.0756.  The baker’s percents look like this:

100%, Flour, 1142 g.
64.8%, Water, 740 g.
2.63%, Salt, 30 g.
1.75%, Sugar, 20 g.
3.94%, Oil, 45 g.
0.273%, Instant dry yeast (IDY), 3.12 g.
Total dough batch weight = 1980.12 g.
Individual dough ball weight = 1980.12/6 = 330.02 g.

I ran the above numbers through the Lehmann dough calculator at http://www.pizzamaking.com/dough_calculator.html and the numbers look right. They are not exactly what I calculated using a hand calculator, because of the number of decimal places I used, but they are very close. So it is safe to use the dough calculator to scale the dough formulation up or down. I didn’t allow for any scrap, so the final numbers may be a bit different. Maybe at some point you can test out the above formulation and report back on whether it is accurate. Any changes might support a new thread rather than putting the results on this thread, even though the formuation achieves a good oven spring and a nice open crumb, both of which are relevant to this thread.

Peter

Offline varasano

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Re: The Nature of the Yeast
« Reply #39 on: October 05, 2006, 04:57:07 PM »
I think the use of the term "steam" may have led some people (including Pizza Shark) to think you were referring to it in the common sense as noted in wikipedia:
LOL... pete, pete pete. You are too nice. I think Pizza Shark's confusion exceeded my use of an accurate, but not common coloquial usage of a word...


 

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