The Fresh Loaf

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The confusing balancing act of Yeast vs. Lactic acid vs. Acetic acid . . . . and thus my too-Mild Sourdough

Ted Wanderhill's picture
Ted Wanderhill

The confusing balancing act of Yeast vs. Lactic acid vs. Acetic acid . . . . and thus my too-Mild Sourdough


I am trying to synthesize all the varying Fresh Loaf Community opinions about how to bring a starter into “balance”, in other words, how to keep its ability to leaven dough (keeping the yeast strong), whilst simultaneously upping the sour flavour.

My breads have veered from too sour and brick-like (and thus the yeast fell out of balance) . . . to what is going on nowadays, that is healthily rising but too mild (very lttle sour) in flavour.

Of course, Debra Wink’s writings in these blogs have been a guiding light, but I have had a bit of trouble converting their wisdoms into basic practice for a newbie like myself. And other Fresh Loaf bloggers have added to my fogginess, probably more due to my inability to harmonize all the knowledges than in any sense of contradiction to Debra Wink’s sound science.

To lay out some of my confusion . . .

J-Monkey, in an article on “Squeezing more Sour from your Sourdough”, advocates keeping the starter stiff. This meshes well with J. Hamelman’s Bread (p. 354), where “acetic acids develop more readily in cool and stiff conditions.” But as I recall, much of Daniel Leader’s writings in Local Bread describe a stiff-dough levain as making a less-sour bread (for there will be more flour for the yeast to eat?) than a liquid levain. And Debra Wink says that a “firm starter produces a milder bread.” Which way to go, stiff or liquid? Many Fresh Loafers seem to prefer a 100% starter, but the stiff (and yet very mild) starter I have been using is 50%, as that advocated by JMonkey and Hamelman.

As for “room temperature”, J-Monkey says to “keep the dough cool”, and in a recent, similarly-themed thread (“Sourdough isn’t Sour”), Matt H. says “The trick is to do a slow, cool fermentation and rise.” I am thus thinking of cooling down my fermentations of the starter after feedings, as well as the fermentation of the dough, to more like 68 or 70 degrees  . . . but then Debra Wink writes about the heterofermenters (!) liking it warm, so as to produce more acetic acid, but just as long as you are very strict about your feeding (maybe every 12 hours, and never letting it “drop back down from the peak”?). Should things thus be more near 75 degrees? But of course, that makes me wonder about creating too much sour-flavouring, and not enough rise-leavening.

Of course, many write about adding rye to a series of refreshments, to build up the acid communities. Is it as simple as that?  And similarly, some say to just do some very long refrigeration/retardings, and let the starter be what it is. Thoughts?

I guess I am just really confused about the game of increasing acetic at the expense of lactic acid (and, does L. SanFranciscus produce both??), and how to bring these bacteria into flavour-producing harmony without impeding the function of yeast.

As you can see, I’ve fallen into the labyrinth.

I was going to simply move into a basic “healing regimen” of having my starter fed at 12 hour intervals with 70% white 20% whole wheat 10% rye (but I wasn’t sure which hydration to go with), and then keeping it at 75 degrees (closer to the ambient temp. in a bakery, where Lacto. SF. Is fed every day . . . ), and staying away from the refrigerator for awhile . . . all via Eric Hanner and Debra Wink’s dialog at:

. . . but I wasn't really sure what Eric meant by "room temperature."

As I’ve said, many of the other methods above seem to flow in different directions. Please excuse my wordiness . . . just trying to lay out all the issues!

Any advice would be much appreciated---Thanks, Ted

Angelo's picture

... of everything that is confusing me also.

Just under you, I have a thread going with many helpful links to solving the mystery that is sourdough and its flavors. Some links recommend the one, some the other. Everytime I think I have a handle on it, I find another post steering me in the total opposite direction for the same results.


Sorry I can't add to this thread, but I will be monitoring it in hopes that someone distills that wealth of information into something us newbies can use. Thanks for posting this.



Debra Wink's picture
Debra Wink

Ted, the answers to your questions are big and many-faceted, and so I won't try to answer them here, today. But here is a thread that I'm adding to as time permits. It may give you some of the answers you're seeking, over time.

Click here: Very liquid sourdough | The Fresh Loaf


Porkbutter's picture

This very topic gets discussed in podcast #19 at

In fact episodes 18,19,@ 20 all deal with sourdough. Well worth listneng to.

nicodvb's picture

If it helps the only certainty in all my experiments seems to be the inevitable shift towards an acetic flavor when bringing the dough to the fridge.

Mini Oven's picture
Mini Oven

organisms.  How you feed and keep your starter has a lot to do with what is happening in the starter.  The patterns you imprint on your starter influence it greatly.   How long you keep the various microorganisms at certain temps and how you keep the available food levels thru their growth stages has a lot to do with what's going on in your starter as well as its flavour profile.  The various organisms respond to what you do including the lack of food and lack of ideal temperature.  Actually we use them along with known limits and "set them up" for a predictable response.  We simplify by calling them just yeasts and lactobacilli but there are many many more than just two types.  These vary somewhat with the flour and the starter's dominant microorganisms-- the ones that thrive with the specific way you treat your starter.