December 18, 2012 - 4:11am
I want to kill the LABs in my starter
Let's assume that I wanted to kill the lactobacilli in my starter, or at least reduce as much as possible their activity (I don't want them to do anything at all: no acid and no enzyme release).
How could I do it without exposing my starter to molds and without inhibiting the vitality of the yeasts, if at all possible? Could the wild yeasts live in a less acidic or even neutral environment?
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:) The folks who make commercial yeast must know.
You can lower the amount of acidity by more frequent feedings, and adusting the hydrations. As i believe yeast tends to multiply faster in a wet environment, go with a liquid starter and refresh it more often?
On the other side...the enzymes and stuff are what makes sourdough bread what it is, why get rid of them?
the raising power of the wild yeasts but get rid of all the rest, without resorting to baker's yeast (it smells too much for me). Acids and enzymes may sound good, but they have too many undesired side effects. In a sourdough starter they can be somewhat lowered or buffered, but I'd like to get rid of them altogether for special occasions :) .
Now if you want to reduce the lactobacilli in part of your starter. Get your starter up to the ideal temperature for production of yeast only and refresh with every first or second yeast reproduction cycle. About every 2 hrs to 3 hrs. I am guessing here! for about 12 hrs. That should do a major job at increasing yeast over bacteria. Then use the active yeast. After using what you need, let the rest stand until it peaks and falls flat (6 to 8 hrs.,good and ripe) and the labs should be back to protect the yeast. Discard and feed. It's a guess but worth a try.
Another idea might be to activate RNA switches by feeding the starter what you want it for. Sort of oversensitize the labs and make them sick. Feed them sugar and starch, no protein or fats. Maybe that might work.
is the right interval to keep the LABs dormant. I remember Debra writing about technical times to wake up the dormant monsters.
You genetic engineering plan reminds me of when I fed the starter with increasing amounts of sugar. It somewhat worked, but acidity ended up increasing.
I didn't suggest changing the genes. Just the switches. epigenetic. :) (just to prevent confusion later on)
Try adding some salt. A hundred years ago, the published way of maintaining a captured wild yeast culture for commercial baking was to make a salty beer and collect the barm. The hops kept down the level of bacteria, as did the salt. If you don't want to go quite so far as that, try maintaining your culture with some salt in it. I'd start with smaller percentages than for baking bread, and work my way up, if I was trying to accomplish your goal. Maybe start with 0.2%?
but the power of the yeasts is visibly reduced respect to when I used water alone. Maybe it's too much? I'll reduce to 0.2%.
The recipe I have here in front of me is as follows.
40 lbs water
10 lbs malt
4 oz hops
mash for 3 hours, strain out the solids, then cool rapidly
4 lbs store (old barm)
2 oz salt
ferment for 36 hours or until it stops hissing
From "The Technology of Bread-Making, Including the Chemistry and Analytical and Practical Testing of Wheat Flour, and Other Materials Employed in Bread-Making and Confectionary", by William Jago, 1921, page 238.
The panetonne makers have a good handle on what you are trying to accomplish with your starter - just the wild yeast.
I've been baking a lot of panettone over the previous 3-4 years. After a lot of failures I finally found my way that worked well with all recipes I tried, but after some time I began to experience big problems. I didn't change anything (sam recipes, same flours, same method), but evidently something changed in the starter itself. The doughs began to dissolve at the second dough or dissolved during proofing or during baking, as if all gluten was totally destroyed. I may be wrong, but I attribute it to the LABs' work. too many acids? too many enzymes?
Of course I used the panettone way to refresh the starter: 45% hydratation and lots of early refreshments.
A couple of years ago, my starter just went all wrong. The dough dissolved into goo and it wouldn't rise. I don't recall if the problem stemmed from the wrong kind of bacteria, or a situation where the LAB population got out of control relative to the yeast population, or excessive enzyme production. I tried to salvage the starter but had no luck. So, I tossed it and started a new one.
Others have had success with a method referred to as "washing" a starter, which is predicated on restoring a healthy balance between the LABs and the yeasts. You might want to search for that term, along with others like proteolysis or gluten attack, just to get a broader view of the possible sources for the problem.
Best of luck.
Paul
Nico, last winter I went through a nasty stretch with a conversion from whole wheat to white starter, and the result was exactly as you both describe here. At a mid point in the development the dough just broke down into mush. You do not say you are pushing your starter to a different feed stock, but nonetheless, while I would not rule out the possibility of proteolysis as Paul suggested, I would certainly add thiole to the keywords list when you search and read up. You can find my blog about my go-round with thioles here. There are some references from Debra Wink that were very helpful.
Good Luck
OldWoodenSpoon
From what I understand, the starter is just fine but Nico wants to know how to use/get/grow just the yeast without the symbiotic baggage that comes with wild yeast cultures.
When making plain bread the starter works perfectly well, with great spring and no side effects, but when making panettone&friends a lot of problems show up. I attribute them to an excess of proteolytic activity and for this reason I'm searching a way to eradicate the cause of the problems: LABs.
This involution is recent, it appeared in november.
Perhaps the solution is to separately cultivate a fruit-based yeast, "yeast water", for those recipes?
less than excited when I did. I also read that someone complained for a lot of dough deterioration when using water yeast.
To clarify I add that I used raisins.
Maybe I should really decide to use tiny percentages of baker's yeast all alone.
Janet Cook seems to have had success mixing the two cultures in the actual dough. Probably fresh fruit produces a stronger culture than preserved fruit. I know that I completely killed a ginger beer culture with just a touch of bottled lemon juice. I tried and tried to recover it, but all it would make thereafter was something with the consistency and odor of motor oil (clean, not used).
Woodenspoon, I'm aware of this frequent deterioration, but I don't think it's the case.
I had that same problem years ago, and I remember it was much more dramatic than what I'm experiencing now. All elasticity was lost, basically the bread spread to infinity and became gluey, but what I have now is different and shows up only after very long fermentations, that generally means after a lot of acid accumulation.
with too long a retardation. Shorten it. also Some ways to denature the flour like scalding or tangzhong or contact someone with a sweet sourdough. Wasn't that a potato and sugar sourdough culture that is sourless?
or feed the dough with lightly roasted flour so active enzymes are denatured in the flour.
What you've described can also be blamed of too much starch damage in the flour or too low a falling number. Either will result in the problems you've described, everything else be equal, of course. Good luck.
HI, I don't think that my collapses are due to low falling number/high amylase activity (at least with the flour I used most ofen) because the fermentation rate of the starter itself seemed to be a bit slower when I refreshed it with that particular flour. As for the others everything can be, of course.
Try refreshing the starter for the usual 4hrs at 28C but in water. When I did this it wiped out the acidity dramatically. Bare in mind that washing away the acidity will compromise the strength of the dough.
It is, fortunately, impossible to kill off a sourdough's entire lactic-acid bacterial population, as long as the culture's medium is grain-based. Think of it this way: every sourdough fermentation is, by essence, a co-fermentation, because there is never just one culture at play. Not unless you throw away your sourdough, create semi-sterile conditions (i.e., laboratory-grade), and directly inoculate a sterile, vacuum-sealed media (e.g., glucose) specifically tailored for whichever yeast culture(s) you might wish to use. The yeast culture(s) will of course be dried, having been isolated, phenotypically sorted, and mailed to you from another lab.
I say this because sourdough is called sourdough for a reason: every sourdough culture that has been documented in the world contains lactic-acid bacteria, but not always yeast, and none of these yeast or bacteria are in any way exclusive to grain-based fermentation systems (de Vuyst, et al., 2005), with the one exception of Lb sanfranciscensis, which itself has too many exceptions to delve in here.
Think of a medium, like, whole wheat flour, as a neighborhood, the place where these bacteria and yeasts sleep, eat, fuck and shit. Depending upon the conditions of the neighborhood, the population's demographics might change, with new, different immigrants moving in and taking over. So, to not stretch this metaphor too thin, a home or artisan baker is more of a real-estate developer than anything. Your neighborhood's conditions affects who decides to move in; maintaining those neighborhood conditions makes them stay, which is the reason bakers insist on using the exact same sourdough regimen daily.
Scientists have charted many known associations between the two groups based upon their environmental circumstances, and have discovered that the lactic-acid bacteria and yeasts that thrive in the grain-based media bakers prefer have also co-evolved to their media and co-inhabitants in such a way that, and especially when Lb. sanfranciscensis is involved, they cannot function optimally (or at all) without the other. This is why the known metrics that govern yeast and lactic-acid bacteria are nearly identical under every imaginable fermentation condition, with a few exceptions.
Sourdough fermentation without lactic-acid bacteria is therefore not sourdough fermentation, at least in any conventional sense. This being said, there are some scientists who have wondered why the artisan-baking community has been so relucant to accept the use of isolated, dried cultures. From their perspective, such cultures affords greater control and predictability over a bread's desired outcome, and it might be one way for you to eliminate the use of lactic-acid bacteria. (There have been a couple of studies on this very subject, all with the same result: bread created with isolated, "wild" yeast cultures is far inferior to bread made with both yeast and lactic-acid bacteria).
I hope this might help.
ahead :-(
Actually I expected this very same reply and for this reason I didn't mention "sourdough" at all, just "starter". I realize that when I use something "wild" by definition I can't have a lot of control on its activity. I can try to direct it in a desired direction, but after all it does what IT wants.
Now, off the top of my head I don't remember why on earth I decided to insist on culturing a sourdough starter knowing in advance that it would give me a lot of troubles. Fortunately I'm still in time.
Technically speaking, "starter," from the context phrased in the question, can only imply a natural starter, as the spontaneous fermentation of wild microflora in a yeasted preferment will have such a negligible impact on the end-state that one might as well chart the influence of other, random outliers, like, say, the lunar cycle.
But here's the thing, and probably more important to note: bakers exert more control over their sourdough culture and its eventual end-result than one might even realise. Through just the three variables of time, temperature, and inoculation amounts a home baker can realise dozens of known, stable yeast-bacterial associations that have repeatable, quantifiable outcomes. When other controllable variables are added, and there are quite a few, a baker can, if she chooses, create a custom culture that behaves in very way she can predict (a very astute baker has all the resources available via Google to calculate, within a precise margin of error, every relevant data point, from exact CO2 output to choosing the quantity and, more importantly, type of volatile aromatic compounds generated). Let us remember that we should not conflate "wild" with "unpredictable." Yes, geese are wild, but, as an entire species, behave in an entirely predictable way, year in, year out.
The question every home baker should really be asking him or herself, and this extends to the whole of the artisan-baking community as well, is: What sort of bread do I want to make? The answer to this question should then imply the materials and methods used, and not the other way around.
Well put, ars pistorica.
Nico, what temperature are you keeping the starter between refreshments, and how acidic does it get? Just barely tangy (if at all), puckeringly tart, or somewhere in between? -dw
Hi Debra!
The temperatures range between 22-23°C during the day and 21-22°C by night. My phmeter is broken, so I can sense the sourness but not measure it. The smell isn't sour at all; the taste is mildly tangy, but it feels as an aftertaste only after several seconds rather than immediately. There's also a mildly bitter tone that I didn't perceive when the starter was in good conditions. The color is creamy. The hydratation is around 45%.
I always refresh my starter with double flour, e.g. 20 gr starter, 18 gr water, 40 gr strong flour (and recently 0.5% salt to try to block the LABs).
Does my description ring any bell?
Thanks,
Nico
Well, firstly, your refreshment ratio isn't going to help in your misguided quest, as you're sporting a 27.5% inoculation rate, which will allow too much acid-transfer, and your fermentation temperature does not offer any comparative growth advantage to wild yeasts over lactic-acid bacteria at the stated temperatures. If you really want to change the nature of your starter to minimise lactic-acid bacterial growth, maintain your starter at a constant 28°, use small inoculation amounts, shit flour, and refresh often. If you can, I'd recommend feeding your starter four times a day to start with, and eventually increasing the refreshment rate to six times a day. Four-hour intervals at the mentioned temperature using bad-quality flour should select for a wild-yeast culture whose main competitive advantage is fast-growth.
I follow your reasoning, but why is shit flour supposed to promote the growth of the yeasts? Is it generally poorer in lactic-acid bacteria or hamper their reproduction?
Hi Nico,
You and I agree on this, I'm sure. Using poor quality flour in the leaven just makes for lack of tolerance in the final dough.
Stronger flour takes longer to break down. I don't follow the logic of using "shit flour" at all.
Debra is on the money with her focus on temperature.
My best wishes to you
Andy
of course I don't understand why not using a resistant flour, unless Ars Pitorica doesn't necessarily intend weak flour as shit flour.
Always nice to see you are present!
Nico
A shit flour is just that: a flour's that not very good, which would tend to mean something from the industrial-milling sector, overly "corrected for" and blended to produce a retail- and wholesale-product with long-term, repeatable . The focus on shit flour here, along with the insistence on inoculation percentage, relates to how available substrates types, as well as population dynamics over time, can select for or against the presence, as well as prevalence, of particular cultures or associations of cultures. This is more of a determinative factor when trying to achieve a particular result than any other stated parameter, because performative differences in every known sourdough yeast and bacteria is shown to be species and not strain specific. Considering the hundreds of known sourdough yeasts and lactic-acid bacteria, as well as their vastly different metabolic requirements, activities and end-products, there would should ostensibly be an infinite number of permutations. Thankfully, there is not, but there are many kinds of outcomes. Surely, then, which culture a baker chooses to employ, whether or not she knows it, is the most important choice she makes.
Just a note to some of the comments. A weak flour does not imply a shit flour, but a flour deficient in certain qualities that allow for fermentation-tolerance, like protein content, incorrect moisture-content, substrate availability, native starch damage, and so on.
Hiya Nico :-)
21-22ºC is a reasonable temperature range, and by your description it seems that the starter is fairly mild. So, if I understand it right, the issue is mainly the unexplained changes you're noticing? I.e., bitterness in the starter, and break down of the dough structure through the long fermentations of the panettone process. Any other problems? Is it rising well?
I have a few more questions:
Let's start there,
dw
Debra, I've been maintaining my starter always at room temperature refreshing every day with that regime since november 2011. The starter itself grows well: it triples in 4-6 hours (less time during the early refreshes) and it gives me wonderful breads every time (I use 1 part of starter and 5 parts of flours, using all possible combinations of bread, durum, wholemeal and white rye flours in the bread dough). There's no bitterness whatsoever in the bread, no other aftertastes other than the mild sourness that breads of this type are supposed to have. The breads raise very well, too, tripling in 8-10 hours at most.
There was no change after the seasons changes, at least not in the autumn->winter transition. Well. by summer the temperatures at home ranged from 30 to 35 degrees, so the turbo mode was activated, but I didn't have any bitterness nor dough breakdown until early december.
I'm following a very traditional process: refresh every day and repeat three early refreshments whenever I have to do a panettone or a very rich dough, delayed by 3-4 hours from each other. Nothing else, no variations. The early refreshments were always made with equal weights of starter and flour, always at 45% hydratation.
I hope I've been a dilgent pupil:). I doubt that my starter can complain with me:)
I'm curious what are the parameters that define "shit flour" ...
Yes please elaborate! I would like to know if my flour is "shit" or not.
I was going to ask ars pistorica to mind the language. But since everyone else is echoing that description it hardly seems worth it. "poor quality flour" would have been fine.
I'm growing a bit bulgar with age, but you are perfectly right Michael:)
Thanks, Micheal, for the reminder.
Sorry, for those speaking French it's farine merde. Google Translate might be able to help for other language speakers!
just like my starter.
For reference here is the full process of my Italian style starter.
Fed always 100g leaven, 48g water 110g flour. Kept at 18-20C every 16hrs in cold water.
Upon refresh i remove the soggy outer layers and take only the inner dough, which is dry and not at all broken down. Protese activity is almost non-existent in my starter.
Before using for panettone I refresh three times at 29C (100g leaven, 100g flour, 48g water). Typically I take 110g leaven on the second and third feed to ensure it'll have the power to move these very rich doughs.
I am having a bit of trouble parsing your sentence. "Kept at 18-20C every 16hrs in cold water." Does this mean you are feeding every 16 hours? Thanks. -Varda (And thanks for your heads up on the language. )
Apologies for the poor wording. Yes fed every 16hrs. Once fed it sits in a bowl of cold water @ 18-20C until the next feed and so on...
Thanks so much for clarifying. -Varda
I'm almost ashamed to ask but... could it be butter to liquify my doughs? I'm perfectly accustomed to the slackening effect of butter, but in my case the dough is really liquified, like a cream.
Butter in italy is almost always a by-product of parmesan production: first milk and its cream are left to ferment (thus acidify) for a lot of time, then part of the fermented cream is removed and treated with some chemical additive to mask part of the sourness before being beaten and sold as butter. Parmesan's pH is supposed to be around 3.4-3.5, thus very acidic. Previously I used to use german butter in my doughs because I liked its taste much better, but since it vanished from the store where i bought it I had to use local butter. German butter is not fermented, it's obtained from cenrifugated and unfermented milk cream, this it's much less sour.
Yesterday I baked another loaf with my starter and it came out great once more. This morning I was preparing another panettone and everything was going really great until I begain to mix in butter. Guess what? it's a cream:-(
Good morning, Nico (well it's morning here---not sure just how many hours separate us : )
Before we try and fix something that maybe isn't broken after all, I want to make sure we're on the same page. When you say ...
... are you talking about leaner "naturally leavened" breads, and only having trouble with richer panettone?
(If you can remember) did your problems begin when you switched from sweet to cultured butter? What butter do other panettone bakers in your area use, and are you using a typical amount? -dw
Good morning, Debra.
As you guessed my lean naturally leavened breads came out well; only rich doughs like panettone are giving me troubles. Now that I think of it last winter I used only german butter(s). My problems emerged only with this particular brand of cultured butter. I'm not totally sure, but generally artisan bakers use Corman butter, a belgian (or maybe dutch) brand famous for it high melting point (it's especially good for laminated doughs such as croissant).
http://www.lechef.be/index.cfm?Content_ID=535144009
The amount of butter in my doughs ranges from 66% to 80% respect to flour. yes, it's heart-clogging but life is short and ...:-)
The other butters I used last winter made the dough very slack, but after a lot of kneading the dough always returned in solid form, while this last one is behaving very differently.
What can you tell me about the parm cheese-making process? Do you know if there are any enzymes added (like rennet or rennin) to coagulate proteins?
Surely there's rennet added to coagulate milk proteins, but I don't know if it's added before the cream is separated from the cheese mass or after it's been separated. As for other enzymes I'm quite sure there aren't: the disciplinar used to make parmesan is very strict and nothing else than milk, rennet, selected ferments and salt is allowed. I should have thought of it!
Well, at least this lines out what your next test should be. If you can't find another butter, you could try making your own from fresh cream (although you may need a lot of it!). Hopefully this will either confirm or rule out the butter as your culprit. I think we need to rule it out before making any other changes :-)
at work:-)
:-)))
This is interesting. I use cultured butter almost exclusively in my baking and I've never encountered the problem you are describing. Mind you, I've never had the joy of making panettone!
The butter's not the problem. Just a random outlier.
To be clear, the concern isn't so much that the butter is cultured, it's that the brand in question is a by-product of cheese-making. And the cheese-making process possibly involves different cultures, and enzymes that alter the structure of proteins. Gluten is protein, and gluten structure is what seems to be at issue in Nico's butter-rich breads. Knowing Nico, I wouldn't dismiss observations like these ...
... as random outliers, without further investigation. Investigate is what we scientists do, because assuming will get us into trouble :-)
That's great, but it's still a random outlier!
Hi! In order to kill bacteria, but not yeast in your starter, feed it with flour and hops tea (instead of pure water) a couple of times. Hops sterilize starters from bacteria, but yeasts are immune to hops action. The only LAB capable of withstanding hops action is actually L.brevis (several strains of L san-francisco).
This method (using hops tea instead of pure water) is used by people who want to cultivate home-made yeasts, not sour starters. I.e exactly what you want: lots of yeast, little or no lactic bacteria. I tried it, and it works perfectly well. You basically boil hops in water and let them sit for 20-6o min. Then strain the liquid, let it come down to room T and use it as liquid when feedinl your starter. After all LAB are gone, you switch back to clean water and flour for a couple of feedings, in order to cleanse the starter from bitter flavor and taste of hops.
mariana
Very interesting.
However the most common strains of LAB found in Italian starters are l.brevis and l.sanfrancisco.
l.brevis spp lindneri and l.sanfrancisco is the same microorganism, according to the genetic analysis. I wasn't talking about 2 different bacteria, only one survives in hops tea/infusion.
They are not the same organism! Well, they are, for all intensive purposes, virtually phylogenetically identical, except for two key differences: Lb sanfranciscensis is the only isolated sourdough microflora exclusive to the sourdough medium (the other 16 varieties of known Lb. brevis are commonly used in a whole range of food-related lactic-acid fermentations), and by the amino acid in the interpeptide bridge of the peptideglican. Lb sanfranciscensis has L-alanine, and Lb. brevis ssp lindneri D-aspartic acid. This makes quite a huge difference in the long-run due to their metabolic potentials. The bulk of this information has been researched by Gobbetti and Vogel (separately), with Vogel's 2011 work revealing many intriguing genomic features of sanfranciscensis. Due to separate evolutionary pressures, sanfranciscensis is considered to be its own species, and the original sourdough organism.
On a separate note, the hops idea is a great thought experiment, but does not work. The inhibitory effects of hops are only realised when there are sufficient quantities of hops resins diluted in the concerned substrate. This works in beer, where the wort is not diluted down. These compounds stay intact, at their required levels, in the finished product. Given your example, as soon as the "hops" starter is refreshed spontaneous fermentation and then re-colonisation by native and ambient lactic-acid bacteria would begin, again, instantly. Oh, and all gram-positive bacteria will still be alive!
Thanks for this tip. I don't know where I can find hops and probably it's unbecessary (these two doughs I prepared with another butter didn't liquify), but this method is worth trying.
That sounds like a very interesting way to test a starter for L san-franciso. Not completely because one could have L.brevis too but if one was not happy with their starter flavour…. To test part of a starter and cultivate the remaining lactobacteria in hopes of improvement toward a SanFrancisco flavour would be interesting. Testing would be like flipping a coin; "heads" it could direct the sour flavour "tails" would be a non-sour yeasty levain.
Hops is grown all over Austria. It even grows wild in my neighborhood. (reminds me of kudsu) For several years grew a wall of it to make shade/blind in part of my garden. The blossoms look like small tissue paper pine cones and hang in clusters.
Hi Mini.
I agree that this info is helpful to test for these strains however your thinking is not the way things are. L.sanfrancisco isn't as special as you make it out to be. It doesn't contribute a special sourness and it's not limited to San Francisco.
L.sanfrancisco is a subspecies of L.brevis. Genetically they are very similar. They are hetero-fermenters found commonly in starters that are continually propagated (ie. starters fed daily) and kept on the warmer side of room temp.
Sourness has more to do with technique than LAB strain.
Michael
Michael, where did that come from?
I'm thinking narrowing down the numbers of Lacto beasties in the culture is another tool in the tool box. I wouldn't dream of messing with my Austrian starter, unless I couldn't find or didn't want to use commercially provided yeast. ...and I just might try it. I certainly know how a lot about manipulating my starter and dough. I don't recommend it for the beginner just getting the grasp of growing starters.
Then again... if hopfen blutten tea was used for starting a starter... would it take two to three weeks to get the right varieties of labs growing? To read that hops tea and hops beer was once the drink of the day as it killed many strains of harmful bacteria in water from the time it arrived from China to Europe in the middle ages, gives me all kinds of ideas. Maybe a Chinese cook or a beer brewer was responsible for propagating the strain or narrowing it down in a more pure form without even knowing it. Chinese medicine applied to a sick starter or bad-water treatment turned it famous! (bet you didn't know I was thinking that!)
Agreed, the bacteria exists in Europe too and elsewhere. Doesn't hurt to have a predictable strain of lacto-bacteria to work with.
Mini Merrye Christmas!
I have a hops vine growing on a trellis (have to work hard to keep it from going wild) and you've got me thinking about experiments come spring. -Varda
The only way to have "a predictable strain of lacto-bacteria to work with" is to purchase a pure culture and run a starter off of it. However, that culture would need to be matched with a proper strain of yeast and probably restarted on a fairly regular basis.
A small update. In order to dispell a myth going on in an italian cuisine forum regarding the use of microwave I've started to refresh a branch of my solid starter with tap water boiled in the microwave the night before. I observed that -contrary to the usual- after 24 hours the dough is still completely intact, not at all slacker.
This makes me wonder if the tap water I use every day for the ordinary refreshments contains "something" (in any form) that makes ordinary refreshments gluey after 24 hours. The flour I use is very strong (almost 15% proteins), there's no reason why it should not resist 24 hours with a 45% hydratation.