Author Topic: Choosing a Starter.  (Read 3250 times)

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Offline arspistorica

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Choosing a Starter.
« on: November 16, 2013, 07:08:34 PM »
The topic of selected species and strains for the use as sourdough starters is an inherently divisive one, with very little of the relevant data published for public consumption.  This paucity reinforces the mythic quality surrounding sourdough cultures, lending the subject an aura that's persisted for centuries.

Personally, I am part of a small but growing movement within the professional baking and pizzamaking sector that aims to bring light onto this and many other topics, a ragtag bunch found in North America, Europe and Australia.

I invite all members of this forum to be sceptical but to remember that the burden of proof, especially on this topic, lies not with me but with those who make the ostensibly outrageous claim they can guarantee the dominance and subsequent stability of selected sourdough starter strains.

Outside of the bigger companies that produce these starters on a commercial scale, like in Germany and Italy, those who sell them lack the training, technological means, financial motivation and/or access to genomic research to even identify the microbiotic composition of the cultures they sell.

This is problem number one.  The second and bigger problem, in my mind, is the ever-changing nature of the game.  Particular lactobacillus and yeast isolates are being regrouped and renamed on a continual basis by researchers as the means of identification increases.  This is particularly problematic for the smaller companies that regularly isolate and breed cultures; without the proper technology and guarantee of laboratory-grade aseptic conditions, cross-contamination is all but an insured end.  Lastly, all sourdough cultures are in a constant state of flux, as a sourdough community is defined by whichever species or group of species are best suited for a particular sourdough matrix at the time.

“...Since these ecosystems are cultured over an extended period of time, even for years, the dynamic component is a fundamental feature of this complexity; particularly for type I sourdoughs, where backslopping propagation allows the regular introduction of water and flour but also the removal of a portion of the sourdough volume.  As a consequence, the stability of sourdough characteristics is frequently disturbed.  Interestingly, this dynamic perspective has rarely been taken into account in the literature.  Even if an apparent stability is observed, sourdoughs still continue to evolve slowly.” +

Compounding this issue is the lack of research into these topics.  The science here is very new, set atop an ever-shifting landscape as the human understanding of the microbiotic realm continues to change.  This is increasingly the case in what is now referred to as the “post-genomic era” of microbiology.  That we know more now than ever before still does little to answer all the questions bakers and pizzamakers have regarding the nature of their cultures.

Decades-old assumptions are being over-turned on a weekly basis, such as the idea behind geographical specificity in determining the composition of microbiotic cultures.  As Luc de Vuyst, et al., writes:

“Whereas it has been initially thought that a relationship exists between geographical origin of a particular sourdough and its associated microbiota, this apparent region specificity seems to be a consequence of the interpretation of concomitant research results.” *

This new era of research is showing there is great uniformity to the world's food fermentations, especially as more and more species are discovered and their entire genomes mapped.  Differences now seem to lie at the strain level rather than species.

Because microorganisms evolve at a much faster pace than the larger organisms they inhabit, backslopping enables the creation of an environment always in flux.  Few, if any, bakers or pizzamakers control the wheat lots and their subsequent fraction blended into flour she uses, or assures exact temperature specificity when feeding her starter.  There are simply too many variables at play for a person to control.

One industry microbiologist points out, "If you take this sourdough culture and move to Tunisia and start baking there in the ambient temperatures, if we tested the culture after a few months, we'd find something very different.  The strains that currently serve you well, they would begin to be lost and other strains that are there in the background would start to do well.” &

Dr Marco Gobbetti, one of the world's leading researchers in this field, puts it more succinctly:  "Yes, I know that several people claim to have stable sourdoughs for decades.  In my experience, this is extremely rare.” &

In the case of selected strains for the use as starters, their stability has been called into question in the last decade's worth of research, due to the “competition between the spontaneously growing microbiota and the added sourdough starter culture may lead to the dominance of autochthonous LAB species and/or strains and hence eliminate the added started culture.  This is possibly due to lack of adaptation of the starter culture to the environmental conditions of the particular sourdough ecosystem.” *

This being said, there have only been three studies published on the subject of the viability and long-term stability of selected starter cultures, all with similar results:  few, if any, of the selected strains tend to dominate. (There's also a wealth of unpublished data, which I am willing to share privately, as some has not been published yet.  Again, most of these researchers are very approachable and willing to answer unsolicited e-mails from the general public; contact information is available with me.)

“...Only three of the nine starters used dominated throughout 10 days of propagation carried out under rigorously standardised conditions.  The others were outcompeted by the autochthonous population of the wheat flour and disappeared progressively starting from the first day of propagation . . . One autochthonous strain of L. sanfranciscensis was found to be dominant in all sourdoughs.” #

This will likely be my last post on these boards, which I have found less than welcoming.  I hope those reading this keep an open mind, and, more than anything, contact those who sell starter cultures and ask the relevant questions:  What is the composition of the culture (i.e., which species and strains)?  What methods were used in the identification of the species?  What methods were used to test the putative dominance of these species?  How many trials were performed and on how many flours, etc.?

--
+ “Description of a French natural wheat sourdough over 10 consecutive days focussing on the lactobacilli present in the microbiota,” Leeuwenhoek et al., 19 May 2011, Springer Science & Business Media.

* "Microbial ecology of sourdough fermentations: Diverse or uniform?”  De Vuyst, et al.  February 2014.  Food Microbiology, Volume 37, Pages 11 – 29.

& “Could the 100-year-old sourdough be a myth?” BBC Food, 16.September.2012.  Angle, Emily.  Weatherhill, Emma.

# “Taxonomic Structure and Monitoring of the Dominant Population of Lactic Acid Bacteria during Wheat Flour Sourdough Type I Propagation Using Lactobacillus sanfranciscensis Starters.”  Siragusa, Sonya, et al.  2009, Applied Environmental Microbiology.
« Last Edit: November 16, 2013, 09:38:38 PM by arspistorica »
"Senza il mio territorio sarei solo un panificatore."
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Offline arspistorica

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Re: Choosing a Starter.
« Reply #1 on: November 16, 2013, 09:18:51 PM »
Two rules of thumb.

First, if the company or person plying you with a selected sourdough culture cannot specify both the species and strain, then he or she cannot guarantee the dominance or stability of the culture; both are prerequisites to performing controlled experiments to verify the dominance of a particular strain through repeated propagation, especially via different process parameters and materials (e.g., flour type or fractions used).  Knowing the particular strain is important due to the ubiquity at the species level (as below).

Second, to those who think they "taste" a difference between two different starters, remember that flavour in cereal fermentations comes from only one of three places:  the fermentative culture used, the type of grain, and the baking process.

Because of the high degree of uniformity in starter microbiota at the species level, the metabolites that form aromatic volatile compounds and their precursors from cultures also tend toward uniformity (especially if propagated in the same grain), with the highest degree of difference coming from type of lactobacilli.  I.e., whether the organism is obligately homofermentative, facultatively heterofermentative or obligately heterofermentative.

"With respect to the microorganisms involved, on the basis of a survey of 87 publications, Lb. plantarum, Lb. brevis, Lb. fermentum, and Lb. sanfranciscensis are the prevailing LAB species during sourdough fermentation, irrespective of flour type used." *

Three of the four mentioned are obligately heterofermentative, with two strictly metabolising maltose as the preferred carbon source (Lb fermentum and Lb sanfranciscensis), and all producing approximately similar volatile aromatic compounds and/or precursors under equal fermentative circumstances.  The odd lactobacilli out is Lb plantarum, a facultative homofermenter that is the most ubiquitous organism in any human food fermentation.  In sourdough fermentations, it tends to be a part of the secondary microflora, but when it is the dominant organism, the flavour profile generated is easy to spot (there's usually an overproduction of ornithine, resulting in an overabundance of "roasted" and "burnt" notes, as well as lopsided and "harsh metallic" flavours).

All this being said, most dominant organisms in sourdough fermentations are obligate heterofermenters, thus producing similar flavour profiles; for those who "taste" differences, I would argue it's as much placebo as anything else.  Yeast species are even less diverse.

It's been my sincere belief for quite some time that we are all making the same pizza and the same bread, that the similarities are much greater than the differences.

--

* As above.
« Last Edit: November 16, 2013, 09:27:11 PM by arspistorica »
"Senza il mio territorio sarei solo un panificatore."
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Offline Mmmph

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Re: Choosing a Starter.
« Reply #2 on: November 16, 2013, 10:59:46 PM »
All these posts remind me of that character from "Good Will Hunting".

How do you like them apples?
« Last Edit: November 16, 2013, 11:09:26 PM by Mmmph »
Sono venuto, ho visto, ho mangiato

Mal

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Re: Choosing a Starter.
« Reply #3 on: November 16, 2013, 11:31:45 PM »
The topic of selected species and strains for the use as sourdough starters is an inherently divisive one, with very little of the relevant data published for public consumption.  This paucity reinforces the mythic quality surrounding sourdough cultures, lending the subject an aura that's persisted for centuries.

Personally, I am part of a small but growing movement within the professional baking and pizzamaking sector that aims to bring light onto this and many other topics, a ragtag bunch found in North America, Europe and Australia.

I invite all members of this forum to be sceptical but to remember that the burden of proof, especially on this topic, lies not with me but with those who make the ostensibly outrageous claim they can guarantee the dominance and subsequent stability of selected sourdough starter strains.

Outside of the bigger companies that produce these starters on a commercial scale, like in Germany and Italy, those who sell them lack the training, technological means, financial motivation and/or access to genomic research to even identify the microbiotic composition of the cultures they sell.

This is problem number one.  The second and bigger problem, in my mind, is the ever-changing nature of the game.  Particular lactobacillus and yeast isolates are being regrouped and renamed on a continual basis by researchers as the means of identification increases.  This is particularly problematic for the smaller companies that regularly isolate and breed cultures; without the proper technology and guarantee of laboratory-grade aseptic conditions, cross-contamination is all but an insured end.  Lastly, all sourdough cultures are in a constant state of flux, as a sourdough community is defined by whichever species or group of species are best suited for a particular sourdough matrix at the time.

“...Since these ecosystems are cultured over an extended period of time, even for years, the dynamic component is a fundamental feature of this complexity; particularly for type I sourdoughs, where backslopping propagation allows the regular introduction of water and flour but also the removal of a portion of the sourdough volume.  As a consequence, the stability of sourdough characteristics is frequently disturbed.  Interestingly, this dynamic perspective has rarely been taken into account in the literature.  Even if an apparent stability is observed, sourdoughs still continue to evolve slowly.” +

Compounding this issue is the lack of research into these topics.  The science here is very new, set atop an ever-shifting landscape as the human understanding of the microbiotic realm continues to change.  This is increasingly the case in what is now referred to as the “post-genomic era” of microbiology.  That we know more now than ever before still does little to answer all the questions bakers and pizzamakers have regarding the nature of their cultures.

Decades-old assumptions are being over-turned on a weekly basis, such as the idea behind geographical specificity in determining the composition of microbiotic cultures.  As Luc de Vuyst, et al., writes:

“Whereas it has been initially thought that a relationship exists between geographical origin of a particular sourdough and its associated microbiota, this apparent region specificity seems to be a consequence of the interpretation of concomitant research results.” *

This new era of research is showing there is great uniformity to the world's food fermentations, especially as more and more species are discovered and their entire genomes mapped.  Differences now seem to lie at the strain level rather than species.

Because microorganisms evolve at a much faster pace than the larger organisms they inhabit, backslopping enables the creation of an environment always in flux.  Few, if any, bakers or pizzamakers control the wheat lots and their subsequent fraction blended into flour she uses, or assures exact temperature specificity when feeding her starter.  There are simply too many variables at play for a person to control.

One industry microbiologist points out, "If you take this sourdough culture and move to Tunisia and start baking there in the ambient temperatures, if we tested the culture after a few months, we'd find something very different.  The strains that currently serve you well, they would begin to be lost and other strains that are there in the background would start to do well.” &

Dr Marco Gobbetti, one of the world's leading researchers in this field, puts it more succinctly:  "Yes, I know that several people claim to have stable sourdoughs for decades.  In my experience, this is extremely rare.” &

In the case of selected strains for the use as starters, their stability has been called into question in the last decade's worth of research, due to the “competition between the spontaneously growing microbiota and the added sourdough starter culture may lead to the dominance of autochthonous LAB species and/or strains and hence eliminate the added started culture.  This is possibly due to lack of adaptation of the starter culture to the environmental conditions of the particular sourdough ecosystem.” *

This being said, there have only been three studies published on the subject of the viability and long-term stability of selected starter cultures, all with similar results:  few, if any, of the selected strains tend to dominate. (There's also a wealth of unpublished data, which I am willing to share privately, as some has not been published yet.  Again, most of these researchers are very approachable and willing to answer unsolicited e-mails from the general public; contact information is available with me.)

“...Only three of the nine starters used dominated throughout 10 days of propagation carried out under rigorously standardised conditions.  The others were outcompeted by the autochthonous population of the wheat flour and disappeared progressively starting from the first day of propagation . . . One autochthonous strain of L. sanfranciscensis was found to be dominant in all sourdoughs.” #

This will likely be my last post on these boards, which I have found less than welcoming.  I hope those reading this keep an open mind, and, more than anything, contact those who sell starter cultures and ask the relevant questions:  What is the composition of the culture (i.e., which species and strains)?  What methods were used in the identification of the species?  What methods were used to test the putative dominance of these species?  How many trials were performed and on how many flours, etc.?

--
+ “Description of a French natural wheat sourdough over 10 consecutive days focussing on the lactobacilli present in the microbiota,” Leeuwenhoek et al., 19 May 2011, Springer Science & Business Media.

* "Microbial ecology of sourdough fermentations: Diverse or uniform?”  De Vuyst, et al.  February 2014.  Food Microbiology, Volume 37, Pages 11 – 29.

& “Could the 100-year-old sourdough be a myth?” BBC Food, 16.September.2012.  Angle, Emily.  Weatherhill, Emma.

# “Taxonomic Structure and Monitoring of the Dominant Population of Lactic Acid Bacteria during Wheat Flour Sourdough Type I Propagation Using Lactobacillus sanfranciscensis Starters.”  Siragusa, Sonya, et al.  2009, Applied Environmental Microbiology.

Fantastic post. This questioning of geographic diversity in starter cultures is not limited to sourdough. Recent research in the US on the microbiata of cheese cultures has called into question many aspects of "terroir" in traditional european cheese. Technique, not terroir seems to be the overwhelming contributor to diversity of end product.

Offline arspistorica

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Re: Choosing a Starter.
« Reply #4 on: November 16, 2013, 11:46:06 PM »
Fantastic post. This questioning of geographic diversity in starter cultures is not limited to sourdough. Recent research in the US on the microbiata of cheese cultures has called into question many aspects of "terroir" in traditional european cheese. Technique, not terroir seems to be the overwhelming contributor to diversity of end product.

Blame it on the light being shed from this so-called "post-genomic" era.  The same's happening across the spectrum in every human food fermentation being researched at the moment, regardless of chosen substrate:  in traditional meat-based fermentations, such as air-dried sausages or hams (Lb sakei and/or Lb curvatus); in wine and all naturally-fermented alcoholic beverages (Oenicoccus oeni); vegetable and/or fruit pickles (Lb plantarum, if microaerophilic); and so on.  The idea of "terroir," as you say, is slowly being ditched by the vanguard in winemaking research, something especially easy given global warming's impact on the wine-growing regions of the world!
"Senza il mio territorio sarei solo un panificatore."
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Offline arspistorica

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Re: Choosing a Starter.
« Reply #5 on: November 17, 2013, 12:24:31 AM »
All these posts remind me of that character from "Good Will Hunting".

How do you like them apples?

I appreciate the sentiment!  It's easy to be an armchair critic, while it's another thing entirely altogether to put your money where your mouth is.

A bit about myself, briefly.

I am the founder and owner of Australia's only 100% sourdough bakery and pizzeria, specialising in what I'd call quasi-Italianate bread, pizze, and viennoiserie (the latter is what sets me apart from everybody else).  I also founded the country's first and only chemical- and pesticide-free wheat pool (sort of like a grain coop), which specialises in heirloom grains, especially those that are a part of the Land Institute's wheat germplasm (for annualised wheat), as well as a flour line that mills flours extracted similarly to those found in Northern Europe, by ash content (as well as a whole lot of considerations we have been working with millers and milling scientists around the world to get right!).  The wheat pool is of particular importance to me, especially as climate change wreaks havoc on the main grain-growing areas in this country, as well as guaranteeing an above-market fair price for those small farmers who are dedicated to the long-term effort of growing grains that have a lower yield with greater uncertainty; we are trying to increase interest and production in those grains that will thrive better in land that is, both, highly arid and saline, the growing conditions that not only face Australia but most of the world's grain-growing centres.

I was born in the States and raised in Texas, Arizona and Kansas.  I was a regular customer and friend of Chris Bianco's in the late 1990s, before he or his burgeoning empire became the media darlings they are today.  He remains my biggest culinary influence.  The lesson I learned from him has to do with sourcing, which is why I make my mozzarella from local milk, cultured from scratch; use a local cold-climate olive oil; work directly with local growers to develop the tomatoes I want, as well as growing rare-breed fruits and vegetables; make our own salumi; build relationships with grain growers and custom-mill our grains; and so on.  For me, using what's around you is the essence of the true Italian culinary spirit, rather than a slavish devotion to importing ingredients of suspect origin from Italy.

I am youngish (35) but have worked in hospitality for 20 years.  Professionally, I worked and trained in New York City, where I helped run restaurants for Mario Batali, Thomas Keller, Sam Mason and Gordon Ramsay, amongst others, as well as for Daniel Chirico in Melbourne.  I left NYC for Australia at approximately the same time Anthony decamped to SF; I've been here ever since.

I also have Asperger's, which often makes me aloof, as I'm very passionate about what I do.

I am not new to this forum; I have different handles and have been here since the beginning.

I began a project in earnest (on my own time and money) to help link the cereal and milling sciences as well as relevant fermentation microbiology to the independent baking and pizzamaking community.  I have found experts on the science side of things to be very welcoming and helpful, as well as those in the worldwide professional baking and pizzamaking community to be very open to what's being discovered by researchers at the moment.  I do all this while also working 100 hours per week.

If you (or anybody else on the forum) are not interested, that's cool.  Please, critique away, but, if you are, please make it substantive.  In general, I'm just here to learn and share what I know.  As Danny Meyer says, "All boats rise with the tide."
« Last Edit: November 17, 2013, 02:21:46 AM by arspistorica »
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Online TXCraig1

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Re: Choosing a Starter.
« Reply #6 on: November 17, 2013, 12:54:43 PM »
It's easy to be an armchair critic, while it's another thing entirely altogether to put your money where your mouth is.

I'm curious; specifically what are you saying this comment?

As for not feeling welcome, I suggest you grow thicker skin. As far as I'm concerned, you are welcome here. Notwithstanding, when you come in and try to buy credibility by gratuitously throwing around a bunch of $20 words in answers to questions that weren't asked or at best are tangentially related, you might expect some push back.

What is the name of your bakery/pizzeria?
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
Craig's Neapolitan Garage

Mal

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Re: Choosing a Starter.
« Reply #7 on: November 17, 2013, 01:22:48 PM »
I'm curious; specifically what are you saying this comment?

As for not feeling welcome, I suggest you grow thicker skin. As far as I'm concerned, you are welcome here. Notwithstanding, when you come in and try to buy credibility by gratuitously throwing around a bunch of $20 words in answers to questions that weren't asked or at best are tangentially related, you might expect some push back.

What is the name of your bakery/pizzeria?

I've been aware of Ian (Arspistorica)'s work from various other websites and he is absolutely the real deal. Without doubt one of the most knowledgable (and experienced) people I've come across with regards to all things sourdough. Pizzamaking.com is truly fortunate to have him as a member.

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Re: Choosing a Starter.
« Reply #8 on: November 17, 2013, 01:30:15 PM »
I've been aware of Ian (Arspistorica)'s work from various other websites and he is absolutely the real deal. Without doubt one of the most knowledgable (and experienced) people I've come across with regards to all things sourdough. Pizzamaking.com is truly fortunate to have him as a member.

On what other sites  have you followed his work?

I don't doubt he has some knowledge. I'll withhold judgement whether or not PM is fortunate to have him as a member.
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
Craig's Neapolitan Garage


Mal

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Re: Choosing a Starter.
« Reply #9 on: November 17, 2013, 01:37:45 PM »
On what other sites  have you followed his work?

I don't doubt he has some knowledge. I'll withhold judgement whether or not PM is fortunate to have him as a member.

The Fresh Loaf and also his own blog (which is sadly offline last I checked?  but he had some incredible posts on there at the beginning of the year). Last I heard, Ian was setting up a bakery/pizzeria in Tasmania with a related milling project which I believe one of the guys at The Fresh Loaf (PiP aka Phil?) , an accomplished baker in his own right, visited earlier this year.
« Last Edit: November 17, 2013, 01:40:29 PM by Mal »

Online TXCraig1

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Re: Choosing a Starter.
« Reply #10 on: November 17, 2013, 01:43:01 PM »
The Fresh Loaf

He posted there for what? a month? And you got all that?
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
Craig's Neapolitan Garage

Offline arspistorica

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Re: Choosing a Starter.
« Reply #11 on: November 17, 2013, 04:12:33 PM »
He posted there for what? a month? And you got all that?

A month's nothing, as I osmotically-transmitted my knowledge to Mal! (Thankfully, my knowledge base is very, very small.)
"Senza il mio territorio sarei solo un panificatore."
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Offline arspistorica

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Re: Choosing a Starter.
« Reply #12 on: November 18, 2013, 02:08:25 AM »
I'm curious; specifically what are you saying this comment?

As for not feeling welcome, I suggest you grow thicker skin. As far as I'm concerned, you are welcome here. Notwithstanding, when you come in and try to buy credibility by gratuitously throwing around a bunch of $20 words in answers to questions that weren't asked or at best are tangentially related, you might expect some push back.

What is the name of your bakery/pizzeria?

My bakery's called Apiece Bread & Coffee, a neighbourhood joint specialising in naturally-leavened breads, pizze and viennoiserie.  AB&C, like so many Italian bakeries, does not differentiate between its pizze or bread; these are both products it happens to serve.

As far as pizze are concerned, I am only practically limited by my oven, a four-deck steam-injected Moffat Artisan.  Its maker bills it as a "pizza" oven, but its deck height is too high to be thought of as such, despite being able to reach consistent top-end temperatures of nearly 385°C.  Its deck length is also too short to be thought of as a proper bread oven, too!

AB&C makes three styles of pizza.  Two are in the Roman a' taglio vein, owing much to Campo de' Fiori, Pizzarium, and Sullivan St Bakery.  The subsequent doughs are made from high-extract flour (90%) with a low- to medium-protein content and are generously hydrated, often up to 90%.  The primary difference between the two is that one is hearth-baked, while the other is baked in rectangular sheet-trays.

The second style is hearth-baked, with its parentage somewhere in, both, Campania and New York City.  Its heritage pays homage to Pino 'Joe' Pozzuoli, Chris Bianco and Dom DeMarco, as well as countless joints throughout Campania.  This dough is also highly hydrated for its category, sometimes up to 76%.

I love working with high-hydration doughs; no bread is done with less than 80%.  All doughs are based upon flour that is as freshly roller-milled as close to the day of making them as possible, in addition to receiving a healthy dose of freshly-milled whole-wheat flour in the bakery.

Perhaps the only other thing I can add is that I do not retard any of my starters or doughs; I use only ambient-temperature fermentations, as almost all Italians do.  So, while some may want to categorise as what I do as being overly analytical and lacking any soul, I'd beg to differ, as I try to flow with the rhythm set by my doughs, and not vice-versa.  I agree with Chris Bianco's sentiment that when "you watch these guys in Europe, they stand there with a cigarette and when the ashes hit the ground it's time to proof out the dough, or -- there's a cadence to it, a very organic cadence to it."  Science, for me, is the jumping off point, and answers very little in the ultimate scheme of things, as it does not account for taste or creativity.


[Edit:  Sorry for lopsided photos.  I tend not to take a lot of photos of my work, but I can and will if people are interested, all pizze included!]
« Last Edit: November 18, 2013, 04:45:35 AM by arspistorica »
"Senza il mio territorio sarei solo un panificatore."
                                  -Franco Pepe

Offline arspistorica

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Re: Choosing a Starter.
« Reply #13 on: November 18, 2013, 02:11:13 AM »
Guess the only difference between what I do and most bakeries is there's no commercial yeast in house!

It should also be said I always thought I would open a wood-fired pizza joint first and a bakery second, especially because I have a very strong wine and beer background.  I still plan on doing so one day, but life's circumstances dropped a bakery that also does pizza in my lap first.
« Last Edit: November 18, 2013, 02:40:28 AM by arspistorica »
"Senza il mio territorio sarei solo un panificatore."
                                  -Franco Pepe

Mal

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Re: Choosing a Starter.
« Reply #14 on: November 18, 2013, 05:38:57 AM »
Great pics Ian. Lovely to see your bakery in full swing. Kudos on the sourdough-leavened cornetti! With those pastries, does the acidity affect the dough strength? and if so are there extra measures you take to ensure good oven spring/layers/"open" crumb in the final product?

Offline arspistorica

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Re: Choosing a Starter.
« Reply #15 on: November 18, 2013, 06:27:24 AM »
Acidity matters less in Italian-style breakfast pastries, despite most Italian pastry chefs fretting over the final acid load.  This is due to primarily to a much higher than average sugar content (most Italian-style viennoiserie products contain more than double the amount of their French or Austrian counterparts, minus a lot of the sourdough cornetti formula out there), which, due to osmotic stress, has a suppressive effect on LAB but an immediate impact on yeast activity.  The only worry with too much acid would come from either refrigerating the product overnight and/or from an inordinately long rise time, at which point the sucrose amounts would be depleted to levels the LAB could cope with.  Additionally, all my morning pastries are made with dough starters that prepare the culture for the increased osmotic stress it is about to encounter in the final dough, which is no different than typical production for panettone, pan d'oro, etc.  Everything at the bakery is made in "real time," so there is no overnight refrigeration, etc.

This being said, all my "pasta di mattina" products don't really go through a proper bulk (two to three hours), per se, and require six to twelve hours of a final rise, in shape, at room temperature, including bomboloni, brioscia, cornetti, danimarci, girelle, and so on, in order to achieve the same "openness" as a related product made with commercial yeast.  The only other obvious change, formula-wise, would be the amount of flour prefermented, which, for most of my products, is around 36% of the total flour.
« Last Edit: November 18, 2013, 06:39:53 AM by arspistorica »
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Offline Bill/SFNM

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Re: Choosing a Starter.
« Reply #16 on: November 18, 2013, 06:45:17 AM »
arspistorica,


Please tell me more about the cornetti. Are they the same as Parisian croissants? I make sourdough croissants (ferment/proof @ room temp) at least once a week, often in my home WFO when it is available at the right temp. Currently I am experimenting with different ratios for the butter. If you are willing to share your experiences, please start a new thread in the "Off Topic Foods" board and I'll join you there. I'm more than a little obsessed with croissants lately.   


Offline arspistorica

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Re: Choosing a Starter.
« Reply #17 on: November 18, 2013, 06:50:08 AM »
arspistorica,


Please tell me more about the cornetti. Are they the same as Parisian croissants? I make sourdough croissants (ferment/proof @ room temp) at least once a week, often in my home WFO when it is available at the right temp. Currently I am experimenting with different ratios for the butter. If you are willing to share your experiences, please start a new thread in the "Off Topic Foods" board and I'll join you there. I'm more than a little obsessed with croissants lately.

See you over there.
"Senza il mio territorio sarei solo un panificatore."
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Re: Choosing a Starter.
« Reply #18 on: November 18, 2013, 09:17:07 AM »
My bakery's called Apiece Bread & Coffee, a neighbourhood joint specialising in naturally-leavened breads, pizze and viennoiserie.  AB&C, like so many Italian bakeries, does not differentiate between its pizze or bread; these are both products it happens to serve.

I definitely respect you passion for SD.
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
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Re: Choosing a Starter.
« Reply #19 on: November 18, 2013, 09:42:42 PM »
Ian,
In addition to having multiple cultures that despite have been kept under substantially the same conditions for several years, still have meaningfully different characteristics,  here is an another observation that does not seem to be explained by the science as you have cited it. I’m curious as to your thoughts on this:

I keep the Ischia culture (from sourdo.com) both on the counter at 76F and in my fridge at 35F. The one in the fridge is really just there as a back-up. It is fed every 3-4 months. The culture at room temp has a distinctly sour smell. So long as I feed it at least every 3-4 days, it doesn’t change. However, on several occasions, I have let it go for a week or more without feeding, and when I feed it after the extended period, it develops a cloyingly sweet aroma. It doesn’t matter how frequently I feed it after that, the sour aroma will not return. It maintains the sweet smell. The leavening power doesn’t change materially, just the aroma.

If I take some of the culture from the fridge and revive it, it has the expected sour aroma. I have kept a jar of this on the counter next to the jar that went sweet for several months. Feeding both the same flour in the same ratios, and on the same 3-4 day schedule, the sour one stays sour and the sweet one stays sweet.
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Offline arspistorica

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Re: Choosing a Starter.
« Reply #20 on: November 19, 2013, 12:12:54 AM »
Ian,
In addition to having multiple cultures that despite have been kept under substantially the same conditions for several years, still have meaningfully different characteristics,  here is an another observation that does not seem to be explained by the science as you have cited it. I’m curious as to your thoughts on this:

I keep the Ischia culture (from sourdo.com) both on the counter at 76F and in my fridge at 35F. The one in the fridge is really just there as a back-up. It is fed every 3-4 months. The culture at room temp has a distinctly sour smell. So long as I feed it at least every 3-4 days, it doesn’t change. However, on several occasions, I have let it go for a week or more without feeding, and when I feed it after the extended period, it develops a cloyingly sweet aroma. It doesn’t matter how frequently I feed it after that, the sour aroma will not return. It maintains the sweet smell. The leavening power doesn’t change materially, just the aroma.

If I take some of the culture from the fridge and revive it, it has the expected sour aroma. I have kept a jar of this on the counter next to the jar that went sweet for several months. Feeding both the same flour in the same ratios, and on the same 3-4 day schedule, the sour one stays sour and the sweet one stays sweet.

Great question but hard to answer without knowing more about the feeding regimen, such as flour type (extraction's of particular importance here), final dough temperature, inoculation percentages during refreshments, hydration, and so on.  Lastly, if you have a pH meter, that'd greatly help me understand the scenario.

I'm not sure I understand what a "cloyingly sweet aroma" means for starters, as it can imply several aromatic compounds and starter types.  What does it taste like, both aromatically and in the mouth?  By "sweet" do you mean like orchard fruit, like pineapple, like sweet grains, like honey, like sweet butter, like ...? (One important thing to keep in mind is that "sweet," as a perceived aroma, has nothing to do with residual sugar and/or amount of acid produced; rather, it's an aromatic outcome and there are a wide variety of scenarios that can produce this outcome.) If you keep your starter in 100% hydration I have a good guess as to the what and why, though, as this is a common outcome for wet starters that are left to go for a week or so before being reactivated.

Just some observations, though.  The Ischia culture is likely Lb SF-based, as almost every sourdough culture from central and southern Italy tends to be, process parameters notwithstanding; a three- to four-day feeding cycle has most certainly shifted the culture to a more acidophilic dominant LAB.  Lastly, everything you're saying completely jibes with the science from my perspective:  you've shifted the dominant microbiota of one while maintaining the other.

Sorry I couldn't be of more help.
« Last Edit: November 19, 2013, 12:53:41 PM by arspistorica »
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Re: Choosing a Starter.
« Reply #21 on: November 19, 2013, 12:56:04 PM »
Great question but hard to answer without knowing more about the feeding regimen, such as flour type (extraction's of particular importance here), final dough temperature, inoculation percentages during refreshments, hydration, and so on.  Lastly, if you have a pH meter, that'd greatly help me understand the scenario.

I'm not sure I understand what a "cloyingly sweet aroma" means for starters, as it can imply several aromatic compounds and starter types.  What does it taste like, both aromatically and in the mouth?  By "sweet" do you mean like orchard fruit, like pineapple, like sweet grains, like honey, like sweet butter, like ...? (One important thing to keep in mind is that "sweet," as a perceived aroma, has nothing to do with residual sugar and/or amount of acid produced; rather, it's an aromatic outcome and there are a wide variety of scenarios that can produce this outcome.) If you keep your starter in 100% hydration I have a good guess as to the what and why, though, as this is a common outcome for wet starters that are left to go for a week or so before being reactivated.

Just some observations, though.  The Ischia culture is likely Lb SF-based, as almost every sourdough culture from central and southern Italy tends to be, process parameters notwithstanding; a three- to four-day feeding cycle has most certainly shifted the culture to a more acidophilic dominant LAB.  Lastly, everything you're saying completely jibes with the science from my perspective:  you've shifted the dominant microbiota of one while maintaining the other.

Sorry I couldn't be of more help.

The culture is fed almost exclusively KAAP. On the rare occasion it is fed something else, it’s KABF. It has never been fed any other flour.“Sweet grains” is probably the closest to what it smells like after it changes. It still has as acidic taste though perhaps a bit less pronounced. Notwithstanding, the question I’m asking is much more basic than you’ve assumed in your response. Consider these data points:

1) The culture when fed every 3-4 days does not change noticeably – even over the course of a year or more.
2) On when left unfed for ~7 days, and then fed and revived (by the second feeding it will respond vigorously) the smell of the culture completely changes from sour to sweet. Reguardless of how you define sweet, the smell is distinctly different.
3) Once the smell changes to sweet, regular feeding does not change it back to sour.
4) I can take a sample of the (ostensibly same) culture in the fridge and use it to populate a new culture at room temperature, and it will have the sour smell. So long as I feed it regularly, it will maintain the sour smell.
5) I kept the two (sour and sweet) side by side on the counter for several months, feeding both the same flour in the same ratios at the same time, every 3-4 days. The culture with sour smell kept the sour smell, and the culture with the sweet smell kept the sweet smell.

Quote
you've shifted the dominant microbiota of one while maintaining the other

This much seems obvious, however the observation would also seem to indicate that the shift is only possible when the culture is sufficiently weakened. Neither the flour nor the external environment nor a combination of the two causes a change without the culture being weakened.

The culture in the fridge should also be very weak, right? 99.9%+ of the LAB should be dead according the paper we discussed earlier, yet this does not seem to open the door for the change? I populate a new culture at room temp from the refrigerated culture the same way I feed the culture at room temperature. The difference being the inoculation comes from the refrigerator vs. room temperature. One possibility is that there is something different about the effect of cold exposure on LAB living in a flour suspension vs. CDM or MRS.

So herein lies the question, how can you dismiss out of hand the possibility that the Ischia culture can maintain its integrity if kept healthy? Even if your first response is that the flora in Ischia had already been replaced with different flora, if this happens with whatever replaced Ischia, how do you dismiss the possibility for Ischia or other established cultures for that matter?
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Offline arspistorica

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Re: Choosing a Starter.
« Reply #22 on: November 19, 2013, 01:54:39 PM »
So herein lies the question, how can you dismiss out of hand the possibility that the Ischia culture can maintain its integrity if kept healthy? Even if your first response is that the flora in Ischia had already been replaced with different flora, if this happens with whatever replaced Ischia, how do you dismiss the possibility for Ischia or other established cultures for that matter?

If you want a simple answer, then here you go.

Lb SF has the smallest genome of any lactobacilli; in fact, at the time of its draft sequencing, it had the smallest genome size of any free-living organism.  This is important, and should not be taken lightly.

We know the conditions under which Lb SF will always be dominant; your "predictive model" is based upon such data.  Anything outside of that range and Lb SF falls to the fringes.

Why does it require such a specific pH range for an organism that excretes acid?  Why does it only tolerate a very narrow temperature window for a mesophilic bacterium?  Because those are the external selective conditions its genome evolved to.  Its dominance is only assured in the sourdough matrix, and in that matrix under the conditions we humans put before it.  Those conditions are represented in your predictive model.

Lb SF does not rely upon genetic safeguards to insure its survival, as it doesn't need to; as long as humans make sourdough under the same conditions we always have, it'll remain alive and kickin'.  This same trend is seen across the spectrum of food-based fermentations, with lactobacilli falling into one of two categories:  generalists and specialists.  The specialists have small genomes and rely solely upon the external conditions commonly created by us within their specific substrate and its associated fermentative practices for their dominance; those conditions are responsible for winnowing these bacterial genomes to their miniscule sizes and, as long as those conditions are commonly practiced, then the genome will stay its current size.  Specialists, then, are very particular niche dwellers; they'll die out as soon as their niche does.

Generalists, on the other hand, have much larger genomes and a greater array of genetic stress responses (e.g., Lb plantarum).  Some of these genomes are over 100 times the size of Lb SF, and allow this generalist population to survive under a greater range of conditions than the specialists -- Lb SF included -- can or will tolerate.

The data we know about cold-stress is specific to Lb SF, not most lactobacilli, which have a greater set of genetic responses to up- or down-regulate accordingly to a wider array of stress conditions.  So, Lb SF will dwindle to 1% of its population at 7 days, and 0.1% at 30 days under refrigerated conditions.  We know this.  However, this data is specific to Lb SF and Lb SF only.  One of the reasons I urge bakers and pizzamakers not to put their culture in the fridge (especially longer than 3 - 4 days) is because of the chance of secondary microbiota becoming dominant, ones with larger genome sizes that can tolerate more aciduric or prolonged cold conditions, etc.

There are approximately 60 species of lactobacilli generally found both in the human gastrointestinal tract as well as human food fermentations, and almost all have been recovered from sourdough fermentations.  All have different metabolic requirements and thrive under various life conditions, some hardier than others under a wider set of circumstances.  Think of these as micro-Bear-Gryllses, ready and willing drink their own urine at the drop of a hat.

Research has shown conclusively that in order to be dominant Lb SF-based cultures must be fed on a daily basis when held at ambient temperatures.  If not, other organisms become dominant, which is likely the case with your Ischia culture at room temperature.  The culture out of the fridge had an obvious change, shifting to a culture that is more cold-tolerant (Weissella's, Leuconostoc's, as well as certain Lactobacillus ssp. come to mind).
« Last Edit: November 19, 2013, 02:03:58 PM by arspistorica »
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Offline nickr

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Re: Choosing a Starter.
« Reply #23 on: November 19, 2013, 02:31:54 PM »
This is some fascinating stuff. If I am understanding this right, then Ian you are saying that most likely our refrigerated Ischia culture is no longer Ischia? Is Craig's room temperature culture Ischia?

- Nick

Offline arspistorica

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Re: Choosing a Starter.
« Reply #24 on: November 19, 2013, 02:38:51 PM »
This is some fascinating stuff. If I am understanding this right, then Ian you are saying that most likely our refrigerated Ischia culture is no longer Ischia? Is Craig's room temperature culture Ischia?

- Nick

Hell if I know, but probability strongly points to no, almost certainly not on both cases.  We know there are two different cultures at play in Craig's scenario, which shows cultures can (and do) evolve.  Read up-thread for more specifics.  All I'm saying is, don't bother wasting your time or money purchasing a "culture."  Chances are it's changed from the first time you've refreshed it, and will continue to change if you continually change the conditions under which its held.
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