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clarification on my starter feeding process

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verve's picture
verve

clarification on my starter feeding process

Hi everyone, 

 

I've been baking with sourdough for nearly two years now and I get pretty good results. I've been reading so much contradicting information online that I would appreciate if a few of you experts could put this straight? PLEASE only reply if you are absolutely sure that what you're saying is the correct method, I'd like to hear from true professionals :) 

 

When I feed my starter, I tend to take it out of the fridge and let it rest for an hour or so to get to room temperature. Most websites say that a starter takes 8-12 hours to double, but that has NEVER been the case for me.

 

My room temps are around 21c and my starter tends to double in 6 hours or less. I use plain flour from the supermarket. SO, in order to ensure that when i wake up in the morning, my starter has only just reached maturity, what I tend to do is empty nearly the entire content of my jar at night time, and the fill it up with at least x4 the amount of flour and water (the idea being that it will take the starter a longer time to 'eat' all the flour and water)... By the time my starter doubles, I tend to get more uniform tiny bubbles all over the place rather than those BIG various sized ones... The only way I get big bubbles is when my starter is a bit less hydrated, and I'm not sure if thats related to my question below or not...

 

My question is, am I weakening my starter every time I empty nearly all of it? Would I have a much stronger starer if instead of emptying the jar, I would just use a much bigger jar and feed the starter a much bigger amount? Basically what I'm getting at is, whether the strength of the starter is the same, no matter what amount of starter is being fed to begin with? or is it a case of    'the bigger the amount of starter that you start with before feeding, the stronger it will be after feeding' ?? 

 

sorry if this is a really silly question, I just dont understand the chemistry in the reaction at all... :-/ 

 

 

 

Thanks so much for the help and sorry about the longgggggggggg question :) 

PMcCool's picture
PMcCool

and we're talking weight here, not volume, then the effect will be the same.  If, per your practice, your proportions are 1:4:4, or one part starter to 4 parts water and 4 parts flour by weight, then the initial quantity of starter doesn't matter.  You could feed 10g of starter with 40g of water and 40g of flour.  Or you could feed 843g of starter with 3372g of water and 3372g of flour.  Or any other set of numbers, so long as the proportion remains 1:4:4.  

Here's the thing: there isn't a "correct method".  That's why answers regarding sourdough maintenance are all over the map.  There are a near-infinite number of ways of doing it and each one works.  So long as you are achieving your objectives with your method, then it's another one of the "correct" methods.

Here's what I will suggest: don't focus on your starter doubling.  Instead, focus on it ripening.  It will be ripe when it has expanded as much as it is able and begins to recede.  You will probably notice that the domed or convex surface will begin to look slightly wrinkled or dimpled as the starter begins to fall back.  At that stage of development, it has the maximum number of yeasts and bacteria that it can support and is ready for a new feeding, which might be the next build of your levain or your final dough.

Hope this helps.

Paul

verve's picture
verve

Thats great help Paul thank you so much!! 

 

I have given up on waiting for a double and normally these days I just wait until the top of my starter is at it's bubbliest form, and of course before it begins to recede... So I guess I'm doing it all the right way... 

 

 

Thanks so much :) 

 

 

David

mardil's picture
mardil

Some additional considerations:

1) The volume increase of your sourdough (for what it's worth) depends on the refreshment ratio. More fresh dough per starter means more food for the same number of microbes, hence more CO2 per dough. If you add just a little bit of flour and water to your starter, it will never double because there simply aren't enough fresh nutrients available to be turned into gas.

2) More importantly (as you've experienced), ripening time also depends on refreshment ratio. Naturally, it takes your microbes more time to eat more food.

For these two reasons, the statement "my starter doubles in x hours" etc. is meaningless if no information on refreshment ratio is given.

It would be nice to know in advance what ratio to use in order to have a ripe sourdough at a specific time. I've been looking for such a formula for a while. There's a rule-of-thumb used by German bakers – the Arkady rule – which states that a starter increased by the factor x will take x hours to ripen. (In your case of 1:4:4, there's  a ninefold increase, ergo 9 h.) This rule, however, is theoretically flawed and practically works only very roughly and in a limited time range. It would work for, say, a dog that eats three times a day, six times in two days and so on – a linear correlation. But sourdough microbes multiply as they feed – the population in your starter doubles every few hours (exponential growth). So as you add more hours, you need *exponentially* more fodder.

Ripening time also depends on other factors such as hydration and temperature.

I've been thinking about this recently and, guided by the famous Gaenzle papers and DebraWink's posts in this forum, made up a few formulas that I can share and discuss when I have a little more time.

Mardil

dabrownman's picture
dabrownman

to say on this and want to add to it.  As Paul said, there are a lot of ways to handle starters and levains, they all work and they all are formulated on using the levian in bread when it is at its peak.  The problem comes in when we try to get people to agree on what is the peak and that is pretty much dependent on what kind of bread you are trying to make.

Many Tartine or Forkish loaves require a levain that is made with white flour, very young, refreshed often, very wet and built at room temperature where Labs and yeast reproduce at the same rate.  These levains are bred for the least amount of sour possible.  No waiting for the levains to wrinkle or collapse there.  But the levains used for these breads are considered at their peak for those types of bread.

I want to make a totally different kind of bread.  I want a multigrain one of at least 50% whole grains and I want it to be as sour as possible.  That means whole grain flour for food, cold temperatures to promote lab reproduction over yeast, a stiff starter to reduce the reproductive rate of yeast further.   I want a starter  that has as little yeast in it as possible and as many labs as i can get in it.   I want to build levains from it at cool temperatures too, 64-69F, to promote labs not yeast and I want to build it in at least 3 stages where I can refrigerate it for 24 - 48 hours between stages to allow the labs to reproduce at 3 times the rate of yeast.  I want to use the levain when it has collapsed after at least doubling after the 2nd stage and also the 3rd stage.

So that is the peak for my levain.  Quite different than a Tartine or Forkish peak for their levains but both are used at the peak that is desired.  So the levain method and peak  is totally based on the bread to be made and desired results. 

mardil's picture
mardil

1) A stiff starter will give you more yeast population, not less. Low hydration means a higher concentration of solvents per ml of water, which does slow down growth, but affects LABs more than yeast. You can check that here:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC106434/

and there:

http://samartha.net/SD/docs/DW-post1-4.html

2) There's a brutal method used by some German rye bakers who want to get a lot of acid (to improve the rye) and no yeast (because they use baker's yeast for leavening): They ferment their final build at a high hydration (see above) and at or above 90 °F, which is where LAB growth peaks while yeasts start dying off.

Les Nightingill's picture
Les Nightingill

@mardil where specifically in those (excellent) articles does it suggest that low hydration gives more yeast population? I couldn't find it.

Also, what do you mean by "solvents". This word is not used in either article.

The suggestion in Emily Buehler's Scientific American article (http://blogs.scientificamerican.com/guest-blog/2012/09/28/enzymes-the-little-molecules-that-bake-bread/) is that increased hydration may give faster fermentation as facilitates the mobility of enzymes, resulting in more simple sugars for the yeast to consume.

thanks in advance for any clarification you can offer

Les

mardil's picture
mardil

Sorry Les, I was really unclear about this point.

What Gaenzle says in the 'Growth' paper, as far as I understand it (and I slept through chemistry), is that when you dissolve salts in less water, you get a higher salt concentration (which Gaenzle calls 'ionic strength') in the water, and that is relevant even if you don't take the unusual step of adding salt to your sourdough. I think either there are salts already contained in the flour, or the minerals in the flour (the ash that remains when you burn it) have the same effect when dissolved in water (I guess 'solvate' would be the correct term). Gaenzle also uses the term 'dough yield' instead of 'hydration', a direct translation from German meaning the ratio of dough to flour (or simply: hydration + 100). Here's one of the relevant passages (the other being under 'conclusions'):

"The ionic strength of sourdough is affected by the ash content of the flour [i.e. how 'dark' or 'white' it is], the dough yield (grams of dough/100 g of flour), and the formula. The effect of ionic strength on growth was studied by adjusting ionic strength by the addition of NaCl. The yeast grows in up to 8% NaCl (I 53.2), whereas the growth of lactobacilli is inhibited by 4% NaCl (I 5 1.9). An increasing ionic strength will therefore inhibit the growth of lactobacilli to a much greater degree than it inhibits the growth of yeasts."

Also, in this very enlightening thread , DebraWink says:

"Lowering hydration will slow all the microorganisms, yes, but yeasts are not quite as sensitive to it as the lactobacilli. In other words, the growth rate of the bacteria declines more sharply than that of the yeasts. Sourdough LAB thrive in warmth at high hydrations; low hydration and cool temperatures really slow them down. Yeast benefit from this, because they have less competition from the bacteria, so they have more space, and the resources to expand."

I shoud add here that low temperatures are not really good for the yeast population. At about 75°, yeast and LAB grow at the same rate; above and below, both slow down, but yeast growth declines quicker than LAB growth (here's a graph).

None of this contradicts the Buehler article – indeed, more sugars become available faster when there is more water. But that is as good for Lactic acid bacteria as it is for yeast – and you can only improve yeast content at the expense of LABs and vice versa. If enzyme activity were the only factor, higher hydration would simply meen a quicker ripening process with a largely constant yeast/bacilli ratio.

mardil's picture
mardil

'Solutes' is the word.

dabrownman's picture
dabrownman

hardly black and white

As DW says -'Sourdough LAB thrive in warmth at high hydration; low hydration and cool temperatures really slow them down.

Exactly the same thing can be said about yeast.

I'm guessing that labs still reproduce at a faster rate than yeast does at lower hydration and 36 F.  I have never seen any data where hydration was changed and reproductive rates verified at different temperatures but I sure would like to see it.  If Labs reproduce faster than yeast at higher hydration and at low temperature than they do at low temperature and low hydration - then i will do cold and higher hydration to promote more sour. 

I just haven't seen any data that says the lab to yeast reproduction rate at 36 F is higher when the hydration is 80% or 100% hydration vs 66% hydration.  My guess is that the difference is hardly noticeable and not like the huge way temperature effects reproduction rates of the two.

Maybe Debra Wink has this data and will share it?

mardil's picture
mardil

I'd like to get my hands on this paper, which seems to look at the effect of such parameters in actual dough:

http://link.springer.com/article/10.1007/s00217-003-0867-0

dabrownman's picture
dabrownman

hydration is discussed in these articles either.  Water is the most abundant solvent on this planet though.  Debra Wink has blogged about how higher hydration favor yeast propagation and can be found with the search tool.

i do disagree with some of the comments on the 2nd article where they say that reproduction ceases at 4 C or 36 F.  This is contrary to Ganzel's date hat clearly shows reproduction is taking place at these temperatures and that labs are reproducing at 3 times the rate of yeast but both are very slow.  At yeast best temperature 82 F the yeast is reproducing at 82 times the rat that it does at 36 F .  Labs slow way down from their peak rate at 92 F by a factor of 44 times less but both are still reproducing,

At 36 F labs will double in 39 hours while yeast will take 120 hours to double.

A more liquid levain at room temperature will favor yeast, while high and low temperatures at lower hydration favor Labs.  It is pretty hard to get outside of the an ideal ph range for labs and yeast in a normal SD culture you have at home on the counter or in the fridge but labs can tolerate more acid than yeast since that is what they produce as a by product . So lower ph favors labs too. 

mardil's picture
mardil

Dabrownman, can you find the DebraWink quote by any chance? I've searched, and all I find is the passage I quoted above, which states the opposite. This thread is also about the Belgian and Italian practice of keeping very firm wheat starters because of their (leavening) "strength".

mardil's picture
mardil

It is pretty hard to get outside of the an ideal ph range for labs and yeast in a normal SD culture you have at home on the counter or in the fridge but labs can tolerate more acid than yeast since that is what they produce as a by product . So lower ph favors labs too.

In contrast, Gänzle has found that

The optimum pH for lactobacilli is 5.0 - 5.5 (which is the initial pH of a sourdough with 5 - 20% inoculum), the minimum pH for growth is 3.8 (they usually produce acid until pH 3.6 is reached). […] Yeasts are different: they don't mind the pH at all, but are strongly inhibited by acetic acid, and to a much lesser extent by lactic acid.

The Vollmar and Meuser sourdough machine […] operates with an inoculum of 50%, which makes the dough so acid from the beginning on the the lactobacilli don't like to grow fast. […] It also has a rather high yeast content (if you've read their publication in Cereal Chemistry; yeasts are above 100 million or more than 10% or the total cell counts, while "normal" starters such as the Sanfrancisco starter or the Böcker Reinzucht Stater have only around 10 million or about 1% of the total cell count.

So according to him, lactobacilli are inhibited by pH, yeasts aren't – though they seem to dislike acetic acid for some other reason (its volatility perhaps).

Skibum's picture
Skibum

When I built my starter at the beginning of the summer using the pineapple juice method, the first couple of lean loaves had an almost sweet flavour and definitely no sour at all.  There is definitely some sour tang now that the starter is older, used and abused.

I would like to try and re capture that young flavour and have an experiment going on.  I took my Forkish starter and fed it 1:1:1 with only bread flour on two consecutive days on the counter.  Today I fed one 1:1:1 starter and 1:4:4.  I will bake off a couple of lean hearth loaves side by each to compare the flavour profiles.  Modifying ones starter to change the flavour profile of ones bread is perhaps the most powerful take away for me in Ken's FWSY.  Interesting stuff this wild yeast baking!

Regards, Brian