The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Reproduction Rates of LAB to Yeast (Revisit Please)

DanAyo's picture
DanAyo

Reproduction Rates of LAB to Yeast (Revisit Please)

Can we revisit this chart? Dab introduced this a few years back. Assuming this is accurate, the data below is vital to sourdough flavor. Especially for those who have the equipment to accurately maintain constant temperatures.

Question 1 - I am revealing my ignorance; but what distinguishes L.SF1 from L.SF2? Does this have anything to do with acetic and lactic acids? Hetero- and Homofermentative lactobacilli?

Question 2 - The “L/Y Ratio” is apparently L. SF 1 divided by the Yeast. Why does the ratio only take into account L.SF1 and not also L.SF2. Is the ratio of L.SF2 to Yeast not important? I get Lactobacillus sanfranciscensis. What I don’t get is the two (L.SF1 & L.SF2) distinctions. I have struggled through the papers and am unable to find these answers.

I apreciate your patience as I labor to get a layman’s understanding of this. You can’t possibly dumb this down too much for me ;-))

Dan

inquiring minds want to know

 

Reproduction Rates of LAB to Yeast

Reproduction Rates of LAB and Yeast

 

 

 

 

L/Y

T(°F)

T (°C)

L. SF I

L. SF II

Yeast

Ratio

36

2

0.019

0.016

0.005

3.787

39

4

0.026

0.022

0.008

3.147

43

6

0.035

0.031

0.013

2.634

46

8

0.047

0.043

0.021

2.222

61

16

0.144

0.150

0.114

1.265

64

18

0.187

0.198

0.163

1.145

68

20

0.239

0.259

0.225

1.064

72

22

0.301

0.332

0.295

1.021

75

24

0.374

0.416

0.365

1.024

79

26

0.453

0.508

0.414

1.094

82

28

0.535

0.598

0.417

1.284

86

30

0.609

0.672

0.346

1.760

90

32

0.658

0.706

0.202

3.255

93

34

0.657

0.671

0.050

13.127

 

 

mwilson's picture
mwilson

No. Let's not. Can we erase this chart?

 

"vital to sourdough flavor"

That's absurd!

 

Dan. Focusing on this will not help you to make better bread in any way.

Q1. No and no. L. SF1 and L. SF2 represnt different strains of L. sanfranciscensis.
Q2. Because whomever created this table decided to just disregard half the data.

Honestly. I would forget this.

I mean no disrespect.

DanAyo's picture
DanAyo

So Michael, from the nature of your responce I assume you see no value in the data. In your opinion is the chart, as it relates to temperature, and LAB to Yeast ratio wrong? I understand that this chart is disturbing to you and unfortunately I fear others will be equally disturbed because they hold it as accurate and valuable.

I own a proofer and a retarder. It is my understanding that acetic and lactic acids favor certain temperature ranges as does yeast. I also believe that fermenting at particular temeratures for lengths of time will have a great affect on the flavor of the bread. 

If the chart is heresy in your opinion, would you point me to information that is accurate? My main interest is how temperature affects acetic and lactic acids and yeast.

Pardon me, but I’m not sure what part is absurd about the chart or the post. Please elaborate. I want to learn.

I had, and have NO INTENTIONS of upsetting anyone. If this post is emotional charged, I hope those that reply are disciplined and courteous. After all, we are all friends.

The only purpose of this post is to learn to manipulate flavor using temperature.

Dan

mwilson's picture
mwilson

Everything has value. Even if it is wrong.

The overarching problem here is that this information is being taken at face value and is presented without context.

Every starter is unique and using this data to determine how fast LAB is growing compared to yeast in your unique starter is ultimately pointless because the growth rate of SD microorganisms is dependent upon many, many numerous factors.

For instance, LAB is fundamentally limited by pH whereas yeast is not (according to at least one source).

If the pH is 4.0 what is the LAB to yeast ratio at a given temperature compared to if the pH was 5.0? How does salt effect things? What if my starter is very very acidic?

I'm all for learning and I wish to help you but I don't understand how you think that knowing the growth rates of LAB and yeast in your starter can allow you to manipulate flavour?

Both are responsible for flavour.

Flavour is what is experienced when the bread is eaten and doesn't correlate with the relative growth rates of the microorganisms.

dabrownman's picture
dabrownman

Well I'm sure what got into Michael today but it is time to set the record straight.  The chart is reproduced directly from Ganzel's research report.  I would post this chart he made for it but I can't figure out how to post a chart on this site.  Half the data was not disregarded.

MIchael is right 1 and 2 are different strains of LAB SF.  Ganzel also looked at the effects of: acid, salt and alcohol, on the LAB and Yeast in his study as well as temperature, but Ganzels chart above was his findings for the effects of temperature only and its effects on the reproduction rates and LAB to yeast ratios It doesn't claim to be anything else.  LAB are more sensitive to salt and acid than yeast in the study.  I can't remember which one is more sensitive to alcohol but assume one is.  His report is easily available for anyone to see on the internet and it is a great one to read by the way because salt, acid and alcohol levels and their effects on LAB and yeast are important to know and why Ganzel included them.

On to more interesting things pointed out by Michael.

The thing to remember is that all LAB Fran (In this case 1&2) are not the same even though they are classified as the sam LAB - this study was done before DNA testing as well.  It is just like you land me.  We are mostly 99.9% the same but I am generally quicker, have a higher IQ and am much better looking than most of you, especially Don Baggs, but we are all still Bread Bloggers on the TFL!  Juust kidding of course, but i hope you you get my drift despite your deficiencies:-)   Kidding again but we are different.  They Isolated two different LAB SanFran for this study but they are close enough to drop one if you want to to b ut they are close for a reason.

LAB SanFran is thought to be different than many other LAB, but not all,  most commonly found in SD cultures.  It metabolizes Maltose first and foremost and the yeast in this study does not metabolize Maltose.  Also the yeast in this study metabolize glucose into maltose as a secretion for the LAB San Fran to eat. So, there is supposedly a symbiotic relationship between the two where neither eats the others food and one makes food for the other.

Some of this study is of course based on old 1970's science that may be  totally wrong and really stupid. In reality, there are more than 2-3  dozen each of LAB and Yeast found so far, not counting the hundreds of combinations, that have adapted to live in low pH environments and found in SD cultures - most times multiples of each are found the same culture in fact and they are neven more different than the LAN SanFran in this study.

LAB and yeast both can and do eat many different kinds of sugars and usually no one sugar or the other is elusive to yeast or LAB at all.  The old idea of yeast making CO2 and ethanol and LAB make acids is also less than correct in many cases.  Some LAB, once fructose is depleted. they stop making acid and make guess what - CO2 and ethanol.  Many LAB do this  In fact ,some LAB can make more than half the CO2 and ethanol in a loaf of SD bread.  This sort of makes things more difficult if you have some in your culture no doubt!

The point is that the temperatures mentioned and their effects, and what happens is generally in the ballpark for many yeast and LAB found in a SD cultures regardless what kind of low pH tolerant LAB and yeast you have in your SD culture.  Just like we, you and I, react pretty much the same to the same temperatures because we are human bakers that blog on TFL even though I still am superior to you in many ways and you are superior to Lucy:-)  Kidding again.

When it is hot, we take off clothes to cool off or maybe take a cold shower or jump in the pool,  if you are not Lucy - I prefer a cold adult beverage.  We  move a bit faster, sweat and smell a bit more....pungent.   When it is cold we put on clothes, sweat less,  move more slowly and aren't jumping in the pool to warm up. but we might hit the hot tub and drink a hot adult beverage.    But please, Lucy still has nightmares about that Speedo of yours :-)

That is the way the world is.  It is relative always.  We we are basically the same but slightly different when it comes to the exactness of what we do - Just like LAB 1 and 2, but one is not a single cell microbe able to do calculus, build buildings or quantum computers while the other one can't.  Everything in baking is relative depending on what you have and are trying to do.

Temperature is one of things to take note of and it will help you manipulate and make better bread.  Retarding dough in the fridge to cool and slow it down and putting it in proofers to heat and speed it up are examples of how important temperature can be to bread bakers.  Knowing what it does - is not absurd in any way at all and neither is Ganzel's research or his charts and graphs - even if you have different microbes in your SD culture that act a bit differently. than his.

Success in most things has little or nothing to do with IQ, skill, education or wanting.  It has everything to do with having good character attributes.  That is why so many folks are successful in so many things in life who are not educated, skillful or smart.  They make it because they can and choose to do it. 

They are determined, have perseverance, are fair, decent and honest.  They are persuasive in their gracious, gratefulness and generosity plusa hundred other things required for success.  Skills do and will flow from good character and some skills are nice to have for sure.  Successful folks are tenacious and they are willing to do and sacrifice whatever it takes to get there.  Willingness to do is way more powerful than being smart or educated or skilful.  Beware all wanting, fear, pride and ego.  Fear, pride and ego are the 3 character attributes that cause failure every time and the wanting of anything too much can get in the way of doing what it takes to get it and it is the doing that gets you to success in every endeavor.

The character attributes required for success which are the hardest to have and hold dear are the 3 G's - graciousness, generosity and gratitude.  Without them you can come off as an asshole and everyone can spot one a mile away easy enough, no matter how uneducated and stupid you think they are.  Never forget that the best things in life, good character attributes, can never be bought, no matter how rich you or how much money you spend.  On the other side, many of the things you can buy are probably not worth owning in the first place.

Ask people who you think are successful what made them so I venture to say they will not say they are a great baseball player they are.what a great stock broker they are or what a great painter, oir baker they are.  The is the end resulting skill  The resulting skill happens every time there is good character and none of the bad ones, applied.  Skills are just the gravy that thickens at the end as good character attributes are learned,  gained, molded and used throughout your life.  

Lucy and maybe you, thought this was about, really stupid and uneducated LAB and yeast.....  Silly you :-)  Don't worry, Lucy is laughing at me too and I couldn't care less!

Happy baking

Elsie_iu's picture
Elsie_iu

Most of the concepts you mentioned are not new to me but some of the points are really interesting.

Though I knew that yeast and bacteria have a symbiotic relationship, I have no idea how it works before reading this post. It's fascinating how different species live together in a mutalistic/commentialistic relationship!

I've always thought that LAB either breaks down starch into sugars in aerobic condition or turns glucose into pyruvic acid then lactic acid and ATP during anaerobic lactic acid fermentation. Never have I imagined it is responsible for producing half of the enthanol and CO2!

I always learn something here, not merely about baking but much more :) Please continue to educate us.

dabrownman's picture
dabrownman

and ethanol but many can be made too make some just like they can be made to produce acetic acid instead of lactic.  It's all relative.  When making bread under non laboratory conditions, chances are your LAB are perfectly happy to make acid.  Fructose provides an additional electron receptor for LAB to make acid.  Who said HFCS was bad:-)  Fructose makes up about 2% of the sugar found naturally in flour which oddly seems to be about the right amount - nature is like that many times it seems.  The science is always changing.  97% of all science facts throughout history have been proven wrong by later scientists and why we can never ever have enough of them:-)  They used to say we caught wee beasties out of the air to make a SD culture for bread......now we know they are found right on the gain seeds themselves in way more abundance - almost like they naturally want to be as close to their food as possible - just like Lucy and I

Elsie_iu's picture
Elsie_iu

I treat them the same as other sugar, whether it is plain table sugar, honey, maple syrup or agave. Maybe glucose, fructose, galactose, maltose, sucrose and lactose are all metabolized through different pathways, yet they're still saccharides after all :)

Interesting how nature functions to make everything just right. For instance, the minimum underground depth required to reach the liquifying pressure for gaseous CO2  matches that of where CO2 storage reservoirs are found. As if it's specifically designed for CO2 capture and storage!

The more we learn, the more ignorant we find ourselves to be.

dabrownman's picture
dabrownman

HFCS became evil when the 'Food Police' decided they were bad for you and had to be eliminated.  They decide all kinds of things are bad for you, all the time and want to take them away before you hurt yourself - silly you.  Stuff, like gluten, animal products, wheat, meat, salt, sugar, fat, carbs, bread, plastic straws and utensils, paper plates and cups, soda pop, some want plastic anything banned like tooth picks and ice cream sticks. some want anything made with wood banned or anything that is manufactured or uses too much water to make it, or made with petroleum and who knows what else these whack jobs come up with everyday without end.

They go beyond using their freedom and liberty to think and do what is right for them which is completely normal and think that they are somehow special and privileged enough that they have to do this for you too before you hurt yourself - taking your freedom and rights away. in the process  They moved from normal in every way to Extreme Whack Job Mode so fast and easy they didn't even notice or care at all in any way.  Just ignore them and stay as far away from them as possible.  You can't fix stupid and life is too short!  Plus they will blame you for whatever is wrong with them and call you a Nazi.

When the Whack Jobs want to ban wine, beer and liquor because it uses to much water and is bad for you like they already once - then we have to stop ignoring them:-) 

texasbakerdad's picture
texasbakerdad

Based off of your comment, I think you would like this book... I loved it.

https://www.amazon.com/Art-Natural-Cheesemaking-Traditional-Non-Industrial/dp/1603585788/ref=sr_1_1?ie=UTF8&qid=1532322512&sr=8-1&keywords=the+art+of+...

After reading the book, I was blown away by the stark difference between the sterile commercial cheese making practices vs. the traditional way of making cheese. I learned lots of cool things, some of which is related to bread making, some related to beer brewing, it was just a great book.

Some cool things I learned:

  • All of the microflora needed to make cheese are present in the cows stomach. Young mammels have evolved to have a gut that produces cheese from milk so that milk is easier to digest.
  • Many old cheese makers never cleaned their milking bucket, because the buckets developed a colony of beneficial microflora that they wanted each batch of milk to be exposed too.
  • Keffir grains are awesome!
  • The mold needed to make bluecheese can be safely harvested off of the proper color mold on stale bread.
dabrownman's picture
dabrownman

and my Dad worked there too,  The only cheeses they made that they talked about were cottage and cream cheeses at the pant they worked at. But cheese is one of many food passions for sure.   I worked at the Irish Dairy Board for 20 years in charge of the US operations,  The board was once owned by the Irish government but is now owned by a co-op of Irish dairy farmers and dairy manufacturers who produce milk of course but also make a full range of Dairy Products from milk, butter, dry milk products and all kinds of the finest traditional Irish cheeses.  In the states,the only cheese we made was processed cheese slices - very industrial cool,  but we marketed and distributed not only IDB cheeses but also imported ,warehoused and distributed the finest cheeses and any other food product from all over the world but mainly Europe and Scandinavia.

We distributed  dry, frozen and refrigerated food products.  In the states IDB owned DPI, Distribution Plus Inc where I worked.  I worked there before IDB bought them though.   DPI used to be called Deli Products international, also DPI, when I first started there and it was owned by a private individual in Beverly Hills.  He sold it to Society De Caves in France who owned, Perrier water and Roquefort Cheese with Benier Cheese.  We imported all the very best French cheeses and meats and distributed them all over the USA.  I'm pretty sure that I have seen just about every fine cheese made, aged , shipped, warehoused and eaten:-)  But I have only really made fresh ones myself including goat cheese.   Usually, making aged cheese is way more expensive than buying the very best  but I have always wanted to make them anyway.  We also used to age  hundreds, really thousands of 40# blocks of cheddar cheese for a cheese maker in CA until they were sharp and super sharp  and extra Sharp

I'm sure that I already have this book on a shelf somewhere even though I have never heard of it but I will try to find it at a nearby library:-)  You are right.  It is something that I have always wanted to do and I really need to get after it.  This book seems to be a great place to start so thanks for pointing it out.

In my 20 years of meeting milk and cheese and meat people from all over the world and visiting their farms and plants, farm to table, I never met one that wasn't passionate about it and totally dedicated to the animals and producing the very product possible but these were the finest cheeses in the world too.  So, I don't quite get the author saying The Art of Natural Cheesemaking is the first cheesemaking book to take a political stance against Big Dairy and to criticize both standard industrial and artisanal cheesemaking practices.  I didn't ever set foot in a Kraft cheese plant either though.  But many of the ones I was in were making mass quantities of the best cheese for sure.  So I will give this guy a pass. and chalk his bias up to being ignorant. 

I will say watching cheese being made is really interesting but aging it is like watching paint dry.  Lots of down time and a bit if work every now and then - like making  bread.  I still have a gift tin from Tillamook cheese of their 3 year old white cheddar that has now been aged another 8 years,  the last 3 vac packed.once I thought it was vapor perfect.  I cut some off now and again and it now about a pound :-)  The things we do for perfection!

Thanks again.  

texasbakerdad's picture
texasbakerdad

Most of the author's angst isn't really against the commercial cheese producers. His angst is against the laws that keep people from legally selling cheeses made the traditional way. The way I see it, there are similarities between naturally leavened bread and cheese made the traditional way, except that in America, you can't sell cheese made the traditional way.

dabrownman's picture
dabrownman

Commercial dairy folks have lots of money and lobby legislatures to keep people from doing all kinds of things for fake health reasons that you will kill people indiscriminately or for sport even.   Here in AZ it was illegal to make bread and sell it out of your house.in Maricopa County until last year. and it is still a hassle.   But if you give them enough campaign money, you could probably get them to pass law that you could make biological nerve agents of mass destruction in grade school bathrooms using illegal alien children as workers with no hazmat suits required.

Portus's picture
Portus

If not, I will delete to avoid confusion!

dabrownman's picture
dabrownman

for sure.  I'm pretty sure it matches the chart since they are from the same source.

mwilson's picture
mwilson

Just to be clear this is not an original piece of Ganzle's work.

First clue. It is in colour.
Second clue. It uses Fahrenheit.

This is someone expressing their excel skills.

albacore's picture
albacore

I've always found this chart (which seems to appear just about every week) misleading, at least when taken out of context. It implies that C. milleri is the only yeast in sourdough, even though there are usually plenty of others, including our old friend S. cerevisiae.

S. cerevisiae does not exhibit a sharp decline in growth after 80F is reached (the red curve in the graph). It peaks about 95F.

Lance

dabrownman's picture
dabrownman

It only claims what it claims.  We all know that dozens of different low acid tolerant LAB and yeast are found in SD starters out of the thousands of different kinds that originally could inhabit the culture.  Many studies were done to try to figure out why S. cerevisiae was not found in established SD cultures but was found in ones that were not well established and or started with a pinch of it. and never allowed to get a low pH. S. Cerevisiae is not a strain that likes low pH's and others outcompete it and displace it in established cultures as many studies show but it can be found in tiny traces in some studies I have read.  Some think may be evolving as a different strain better able to handle low pH's better.

mwilson's picture
mwilson

S. Cerevisiae is a species of yeast.

The optimal pH for yeasts varies depending on strain and ecological factors.

Baker's yeast is represented by strains of S. cerevisiae grown industrially which originate from the brewing industry.

S. cerevisiae is found in and originates from the wild. It existed before the domestication and mass production of baker's yeast. It is a key species that has a long history and is responsible for the fermentation of foods and beverages. Notably, beer, wine and bread. It can be found in some cheeses too and many other alcoholic beverages.

Generally speaking yeast prefer an acidic environment.

Wine made from grape must (pH 2.9-3.9) by spontaneous or inoculated fermentation is typically dominated by S. Cerevisiae.

Baker's yeast doesn't do well in a sourdough starter because it is not best adapted to that environment.

However, sourdough starters are often dominated by wild strains of S. Cerevisiae which are adapted to the sourdough environment.

Abe's picture
Abe

"However, sourdough starters are often dominated by wild strains of S. Cerevisiae which are adapted to the sourdough environment".

Would a sourdough starter cultivated, for example, in a cold(er) country naturally do better in colder temperatures than one cultivated in a warm(er) country?

Take any variable wouldn't the yeast and bacteria strains adapt to work best for that environment? Which is why a table predicting a sourdough starter capabilities can't be accurate?

I've been thinking of making a starter from scratch but including 2% salt from the beginning thus encouraging the strongest of strains. Would this work?

albacore's picture
albacore

My hero Gerard Rubaud used salt in his starters and levains, even when creating  a new starter; probably at more like 1% than 2%.

It is a practice that I follow, so far with good results.

Lance

Abe's picture
Abe

I've done salt in starter builds and levains but never from scratch. Mainly just to slow it down.

I think a new experiment is on the way.

albacore's picture
albacore
Abe's picture
Abe

Going to take a look and I'm sure I'll be back for your help.

dabrownman's picture
dabrownman

this yeast dominates a SD starter?  I find plenty where it is supplanted by other forms of yeast that tolerate a low acid and one where a bakery put it in their SD culture every week for some reason but the rest are all dominated and I mean dominated by other strains of yeast.

mwilson's picture
mwilson

If you are looking for proof then surely you need only look at the results of the Rob Dunn project.

http://robdunnlab.com/projects/sourdough/map/

DanAyo's picture
DanAyo

First off, I really what to thank Dab for his patience with me. Your reply above repeats some of what you’ve already written me. But it was not in vain... I often find myself a victim of improper assumptions. I think I am confusing Lactobacillus Sanfranciscensis (L.SF) with Acetic and Lactic acids. BikeProf recommended Debra’s article, Lactic Acid Fermentation in Sourdough , which I went back and re-read again. Believe me when I tell you, I’ve read that article at least a dozen times on separate occasions. Each time I pickup something new. I think I now understand the L.SF1 or L.SF2 or even L.SF13 are variation of the basic Lactobacillus Sanfranciscensis. AND that all “L.SF” can produce (not contain) both Acetic and Lactic acids. According to my understanding of Debbie’s article there are Homo-fermentative (same) and Hetero-fermentative (different) bacteria within all L.SF variations in existence. Now here Is what I think was a great source of confusion for me. LAB is short for Lactic Acid Bacteria, BUT even though these bacteria mostly produce Lactic Acid in the form of Homo-fermentative bacteria they, the LAB also produce Acetic Acids by way of Hetero-fermentative bacteria. AND Hetero produces both Lactic and Acetic acids along with CO2 gas, amoung other things.

So, if the above thinking is correct (and correct me if I’m wrong) the LAB would have better been named LAAB ;-)) LAAB, meaning Lactic Acetic Acid Bacteria. 

Since my driving goal is to produce a sour tasting flavor profile to my liking, what really matters to me is Acetic and Lactic Acids. At this time, unless I learn better, I think the chart shown in my first post is relevant to my goal. Maybe, in the case of my starter, the optimum temp for Lactic acid is 94.5F and the chart claims 93F, I’m still very much in the ball park. 

Dab’s analogy of people being mostly the same finally made sense. Although every starter is probably slightly different, they have much more in common than not. But I will have to say, I am better looking than him, but not nearly as fine as Lucy ;-)) You really would have to see Dab and I side by side in our Speedos <LOL>

Thanks to Michael for his reply. It caused me to dig deeper, and that is always a great thing. If the things we hold dear cannot with stand a challenge, is there any reason to hold on to it?

God, I hope I got most of this right! But if not, I stand to be corrected. But please try to be gentle :D

Dan

dabrownman's picture
dabrownman

All LAB produce Lactic Acid this their name Lactic Acid Bacteria or they would be called something else.  Some produce more than others.  Many can also be forced to produce acetic acid as Dera Wink explains and some produce more than others.  I think that really good SFSD has both the base lactic acid sour and the 'tang' of acetic. This is why if you don't like the taste of your bread that your starter makes then just get some flourn from somewhere else or combination of flours and make a new starter and get a different batch of wee beasties going and your bread will taste different, - you may not like it anymore than before though.  Most people do not like sour bread in the first place and it is us who are nuts to begin with:-)  Knowing what the wee beasties can and cannot do and how to manipulate them is good to know to make the kind of bread you like to eat - especially if you are nuts like us.

The best place to find out anything about bread from all kinds if folks like Debra Wink, Michael, Lucy and David Snyder and so may others is right here.  So many people have taken classes at SFBI and many other professional bread teaching places, great bread book writers like Stan Ginsberg, txfarmer and Shiao-Ping and many pro bakers too, blog about their experiences here.  Plus we see some of the very best bread being produced,with instructions of exactly how to do it, blogged about by some of the very best amature bakers in the entire world right here too.  We get to see it, make some of it, and take in all in every day ....and take it to where ever we we want..

Happy baking TFL way

mwilson's picture
mwilson

Dab my friend. Can you link to or name the paper from Ganzle that includes the chart / table of data that Dan posted please.

Thanks

not.a.crumb.left's picture
not.a.crumb.left

I like the chart from Gänzle  and thank  you Portus for posting.....

I hope I have not totally lost the plot but I think the relevance of this chart is what is the best temperature spot to maximise let's say flavour (although that is subjective) depending on LAB/yeast ratio  associated with not degrading the dough with too long retardation alongside practical timing considerations in baking?

So, what do people say, in an ideal world where we could set our fridge/kitchen/cellar  to XX temp, at what temp would it be best to retard considering balance of LAB and yeast....   Kat

p.s very sorry, if that is totally and utterly over-simplifying.....

 

franbaker's picture
franbaker

Dan, my understanding, limited as it is, is that the same bacteria produce both acids, just in differing amounts under different conditions, one of which is temp.

What I get from this chart is that yeast will be most active at 79-82F (and they produce > 50% of the CO2, so dough probably rises most quickly at those temps), and bacterial activity peaks at 86-93F. What this means to me is that, since the LAB also produce CO2, if I want to bake at ambient temps of 90-93F, when yeast activity is falling off, I may still get CO2 to raise the dough from the LAB activity. And since some bakers raise their dough at something like 90-92F, there must be something about that change in the balance of bacteria and yeast that does something that they want. But the chart doesn't tell me what that is.

I don't think the chart really says anything about the balance of lactic and acetic acids, at least not by itself. What I would need to know is how the metabolism of the bacteria changes at different temps to produce more lactic or acetic acid. 

The rates of activity of the two strains of bacteria look pretty similar, I'm not sure why they left out the second strain, and there may be a footnote or parenthetical statement somewhere in the paper explaining why, but I'm not sure it matters for your purposes.

Does that make sense?

Fran

 

texasbakerdad's picture
texasbakerdad

Do you all have any more info on this chart? Like, what is the LAB and yeast being fed for these growth rates? I am surprised to see the LAB outperforms the yeast.

Maybe it is true that LAB reproduces faster than yeast at all temperatures. The quantity of LAB may not be proportional to the amount of acid. The acid amount is probably the integral of the LAB count over time. Said differently, 50 bacteria over 5 hours produces 5 times more acid than 50 bacteria over 1 hour. And, if the LAB count is also growing as time elapses, your acid totals will grow exponentially. 

bikeprof's picture
bikeprof

is obligately heterofermentative...so homo/hetero should not be what is going on between the two columns.

These data don't do much for me in table form, and there a tons of graphs out there of LAB and yeast growth vs. temp. that I find more helpful in visualizing the relative population dynamics

Even that doesn't really tell us all we need to know, it just gives us one more tool for manipulating fermentation...along with time, refreshment rate, hydration, and flour types (esp. ash content).

And even with all that, in practice the effects of these manipulations to sway the balance in favor of lactic vs acetic acid, or total acid load produced for a given amount of loft, are likely to be effectively deployed in the context of a healthy, vigorous starter (job #1).

Not to say don't worry your pretty little head about such things...learning is always good

On that note...once again...

http://www.thefreshloaf.com//node/10375/lactic-acid-fermentation-sourdough

dabrownman's picture
dabrownman

Detmolder Levain Process and some common sense and the realization that SD cultures can have 10 to 1 more LAB than yeast or 100 to 1 or 1,000 to 1 more LAB thatnyeast, was the basis of Lucy coming up with much of what she does with bread to make it the way we like it - more sour and more flavorful.  So, if you want a less sour bread, you might want to do just the opposite:-)

First off, if you want more sour bread then you want a starter, levain and dough with way more LAB than yeast in it.  More LAB means more acid.  Less yeast means it takes longer for the dough to ferment and proof and the more time that the more LAB have to make acid and more sour bread results.  So, the most important thing is to make your starter, levain and dough have way more LAB than yeast if you want sour bread - you want a high LAB to yeast ratio - per Ganzel's last column of the chart.  Well how do you do this?

There appears to be two ways.  The distance between the maroon (yeast) and blue (LAB) lines on the graph is the LAB to yeast ratio.  The greater distance between the two lines, the greater the LAb to yeast ratio.  what is not shown on the chart or graph is how time affects the bread at each temperature setting but common sense tells us that the more yeast there are and the faster the yeast are reproducing, the faster the bread will ferment and proof and the less time you have before you have to bake the dough. 

What the graph tell us is that the blue and maroon lines are closest together at room temperatures 70-74 F.  The longer you keep the dough at that temperature the lower the LAB to yeast ratio and the less sour your bread will be.  At 93 F, the LAB’s are on steroids but the yeast are restricted.  They act slow, like it is 60 F.  So the LAB to yeast ratio is over 13, the LAB are cranking out the acid like crazy bit the yeast are growing around like it is a cold kitchen giving the LAB to time to make acid before the dough has risen too much and needs to be shaped for proof or baked after final proof.  If you wonder why Lucy says do all of your bench work at 88-94F if you want sour bread?   Wonder no more.  It is the easiest and best way to really put lactic acid sour into your bread.

Debra WInk also says that if you want more sour bread use whole grains.  Dough.Doc and I ran a series of experiments to confirm this where we used tests is whole and white flour at the same hydrations and temperature to determine if this was so and we confirmed it in spades.  The total acid was much greater the more whole grains in the mix at all temperatures and hydrations we tested.  It is like the bran acts as a buffer and provides more nutrients for the LAB to make more acid and to make acid at pH levels that would normally shut off acid production in LAB according to Gazel's work. Rye also seemed to be the best grain for acid production as well for some reason.  Ever wonder why Lucy uses Bran levain?  Wonder no more!  Ever wonder why Lucy used whole grain rye for the NMNF starter?  Wonder no more.  But the NMNF starter process is not based solely on the bran and whole grain rye to increase the LAB to yeast ratio.

You will see that below 60 F the gap between the yeast and LAB lines also widens out making for a greater LAB to yeast ratio.  What is not shown is time but once again common sense come in to play.  We know at low temperatures both LAB and yeast are restricted greatly.  So this means for the LAB to ration to really be meaningfully increase it going to take long time not the couple of hours it takes at 92 F.  When we were working on the NMNF starter project, I contacted Debra Wink about it and she said it is not the temperature that will do what I wanted, Increase the LAB to yeast ratio it was the really really ling time that would be required to make a difference.  She was so right of course and why the NMNF starter is stored in the fridge for up to half a year, at a time very slowly increasing its LAB to yeast ratio as the weeks go by.  But what about the acetic acid?

This is where I rely on the Denolder process that says to get the LAB to make acetic acid you need low temperatures and low hydration.  I have never tested it to know what the best hydration and temperature for how long real are though to fore the LAB to do this switch in acid production.  But if you ever wondered why the NMNF starter is stiffened up to 66% hydration from 100% right before storage wonder no more.  If you ever wonder why so many bakers take their dough, which is also low hydration, and retard it for final proof this is why - they want to get that 'Acetic Acid Tang'.  It is also why Lucy retards her built Bran levains for up to 2 days too.

I once wrote a book about how to solve problems - something they don't teach well in schools for some reason.   Solving problems is what the world is all about.  We all want tomorrow to be better than yesterday.  What drives us and makes the world a better place is we know we are pissed off about some problem.  The first thing that has to happen in problem solving is that you have to realize you have a problem with something and be upset about it enough to do whatever it takes to not make it a problem for you anymore.  If you don't see and feel the problem and pain, you will not do anything to fix it.  So, if you are pissed off about something and want to fix it, then that is good for you and the rest of us most likely.   It is the beginning.

Like most problems, the solution doesn't come from one place.  They are usually both and complex, but still elegantly simple.  Einstein's theory of general relativity comes out of unbelievable complexity but can be written on a piece of paper in less than 2 inches.  But his E-MC2 take the cake for beautiful elegance.  The entire universe is explained on one sheet of paper.  Amazing really and thankfully short reading to know everything about everything ......except LAB and yeast of course:-)

So. someone needs to figure out this Detmolder Process thing once and for all before Lucy goes completely bonkers.so some other, later baker, fixes the problem that your new solution creates, with a new better lie sometime in the future.

DanAyo's picture
DanAyo

In my world, knowledge and understanding, which is much more valuable to me, comes in bits and pieces. It’s kind of like taking a pick axe to a mountain. A little bit here, a little bit there, but given enough small chips, things start to add up. The sum becomes much greater than the individual pieces. For me, it is well worth the mental work, the persistent wondering, and at times the nagging questions. :). Thanks for sticking with me.

With that said I have a question. You said, the bran acts as a buffer and provides more nutrients for the LAB to make more acid and to make acid at pH levels that would normally shut off acid production in LAB”. I don’t doubt this statement, but I don’t understand how that works. I understand that a buffer acts like a shield, guard, or something similar. Would you explain how the buffering affect works as it relates to the quote above?

Danny

dabrownman's picture
dabrownman

Once a white flour culture reaches a low enough pH acid production stops and the culture sits at what ever the lowest pH reached.  But a whole grain one, made with the same amount io LAB in the same starter can continue to reproduce and make even more acid making the culture have a lower pH and a higher Lab to yeast ratio than the white flour one.  There is something in the whole grains, bran and or grrm that allows this to happen but what it is remains another mystery that science need to explain why whole grains do make for a higher LAB to yeast ration and lower pH's than white ones.

DanAyo's picture
DanAyo

So I take it that experimental testing bears the fact, but science is yet to explain it. I appreciate the explanation.

Dan

Bigblue's picture
Bigblue

Epic post. Much appreciated.

dabrownman's picture
dabrownman

on temperature, salt, ethanol and acid

http://aem.asm.org/content/64/7/2616.full#sec-11

mwilson's picture
mwilson

The data posted by Dan does not feature in this paper from Ganzle. There is no discussion of LAB/Yeast ratios.

dabrownman's picture
dabrownman

calculation between the Ganzel LAB and  Yeast data showing that LAB out reproduce yeast at all temperatures.with the higher ratios at high temperatures and low ones.  We are discussing them.  Is that not good enough?.