Starter 2.0 (now THAT'S what I'm talkin' about).

[Shakespeare]

So, this was my last update about the state of my starter:

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=236&topic_id=55339&mesg_id=57218

The rye flour intervention seems to have gotten off to a very successful start. After 48 hours, there's foaming and bubbles, a little rise and collapse, a noticeable change in texture (grainy to viscous), and the one thing that was missing from version 1.0: a definite whiff of alcohol. The original starter did develop the good sour odor, but no whiff of alcohol (the byproduct of yeast production, which is an indication the starter is healthy and growing).

Here's the re-energized starter:



:woohoo:

[Lucinda]

1. Excellent! I'm glad you're back in business!

I just started a rye and AP biga for another type of bread I'm trying, but I plan on giving sourdough a try soon. Your efforts are very inspiring! :D

[Warpy]

2. If you want to keep yeast producing alcohol

the fermentation has to be anaerobic. That means the starter needs to be kept in something that's a lot deeper than it is wide so you'll have a nice blanket of CO2 on top of it, keeping oxygen out of it. If the yeasts have access to oxygen, they'll just continue the process and produce acetic acid, the "sour" in your sourdough starter.

[Shakespeare]

4. It's the bacteria that produce the acetic and lactic acids. The yeast produces alcohol.

The problem with my white flour starter is that yeast is much, much slower to ferment (and produce alcohol) than it is in rye flour.

This is the same jar I've used for years for my starter--so I know it's a good home for it. I just needed to provide a more hospitable nursery for the wild yeasts (with the rye flour), and so far so good. :hi:

[Warpy]

5. No, the yeast produce it

which you'd know if you'd ever been an amateur beer brewer and had a fermentation lock dry out. There's nothing worse than skunky beer.

(or had gone through microbiology in nursing school)

Any bacteria are inhibited by either alcohol or acetic acid.

[Shakespeare]

6. From housewolf's site (because that was the quickest/easiest to pull up):

From a scientific perspective, a sourdough starter is a natural leaven - a mixture of grains and liquid (usually flour and water) inhabited by so-called "wild" yeasts and bacteria which leaven and flavor bread dough. These yeasts are the yeasts that thrive naturally on the surface of grains, fruits and vegetables, in the air and in the soil. The bacteria are certain strains of the so-called benign or "friendly" bacteria Lactobacillus, rod-shaped bacteria that can convert simple sugars into lactic and other acids.

To understand more of what a sourdough is, we need to understand what yeast is. In simplest terms it is a plant. More specifically a fungus, a one-celled life form which digests sugars (such as those contained within the starch in flour) and produces a bit of ethanol (alcohol) and some carbon dioxide (which is what causes the bread to rise). The natural yeasts in a sourdough starter are strains of a yeast family whose scientific name is Sacchraromyces exiges. They are of the same family of yeast as commercial bakers' yeast, whose scientific name is Saccharomyces cerrivasae. The two have what might be called a distant family relationship but differ in one important way. Commercial bakers yeast cannot survive in a very acidic environment whereas natural yeast is very happy to live in such an environment. This is important because the lactobacilli in a sourdough culture produce a lot of lactic and acetic acids (which are what gives sourdough bread its flavor). The acids create an environment too acidic for commercial bakers' yeast, so only natural yeast can live with them.

In a healthy sourdough starter, yeast and lactobacilli thrive in a harmonious symbiotic relationship. This means that they do not compete for the same food and the yeast may actually help feed the lactobacilli. In turn, lactobacilli produce an acidic environment that the yeast like but which is inhospitable to other organisms. Thus the acids in the culture act as a sort of "antibiotic" so that lactobacilli contribute by providing a protective environment for the yeast.

Lactobacilli help bread rise, too. Just like yeast, they digest simple sugars found in flour and produce ethanol and carbon dioxide. In addition, the lactic and acetic acids that they produce flavor the bread with a rich complexity of flavors, sometimes giving it a sour tang.

http://www.angelfire.com/ab/bethsbread/WhatisSourdough.html

Ethanol is a byproduct of yeast development; lactic and acetic acids are produced by the Lactobacillus sanfranciscensis.

[Warpy]

7. Sourdough starter is innoculated with lactobacillus

which tolerates the acetic acid produced by yeast during aerobic fermentation.

Regular aerobic fermentation produces both alcohol and acetic acid, although in smaller quantities. However, these are the things that give leavened bread its characteristic "yeasty" flavor.

[Shakespeare]

8. Edited--I don't know why you keep suggesting that the bacteria doesn't produce the acids.

That's where a portion of its name comes from (lactobacillus/lactic acid). Both the yeast and the bacteria contribute to what becomes sourdough, thanks to their symbiotic relationship. Each have byproducts of growth. The yeast produces SMALL amounts of acid, but its primary byproduct is ethanol. Most of the acids in sourdough come from the bacteria.

:shrug:

[Warpy]

9. I don't know why you think somebody who used

to tutor microbiology doesn't know the metabolism of carbohydrate by yeast!

If you had read my post all the way through, you'd have seen a distinction between commercial sourdough starter which is inoculated with lactobacillus and baking yeast which is not.

[Shakespeare]

10. I DID read your post all the way through.

And please don't assume that I don't know anything about microbiology. I'm not saying you don't understand the process, but I do think you (briefly, and certainly accidentally) confused the function and respective byproducts of the two critters in your earlier response.

You keep saying that the yeast is responsible for producing the acids in the bread. That's not the case. You also said in your original post that fermentation should be kept anaerobic: "If the yeasts have access to oxygen, they'll just continue the process and produce acetic acid, the "sour" in your sourdough starter."

But yeast DO need oxygen: "Unlike bacteria, there are no known yeast species that grow only anaerobically (obligate anaerobes). Yeasts grow best in a neutral or slightly acidic pH environment." Quoting this: http://en.wikipedia.org/wiki/Yeast (take your pick from the bibliography at the end RE sources).

You never brought up baking yeast v. sourdough culture until this post, so I have no idea why you mention it now; we haven't been discussing anything about baking yeast, or how it differs from a sourdough culture.

You also said: "Any bacteria are inhibited by either alcohol or acetic acid." Not entirely; the lactobacillus in sourdough culture tolerates a certain amount of alcohol produced by the yeast, and the yeast in turn tolerates--and in fact flourishes in--a certain amount of acid produced by the bacteria. It's that balanced, symbiotic relationship that makes for a good sourdough.

You seem bent on picking on my original response to you, and I have no idea why. Nothing I said was incorrect. You suggested that I don't have my starter in an appropriate container, and I'm saying I do, and explained why (and it certainly flourished for a couple of years in that container the last time I regularly baked sourdough).

[housewolf]

3. Looking much better!

Kudos to you and good luck with it!

[Shakespeare]

11. Another couple of helpful sourdough sites for starting a starter.

They dovetail nicely with housewolf's sourdough site (heck, she probably knows the authors, too):

http://sourdough.com/blog/sourdom/beginners-blog-starter-scratch

and

http://www.breadtopia.com/sourdough-starter-management/

Spongebob was all perky and bubbly this morning; shouldn't be long now until I'm up and running again with a lively, usable starter. I've REALLY missed regular sourdough baking, and taking a little whiff of that jar a few times a day multiplies my impatience.

More pics as activity increases, and then I'll bore you all to death with endless "look what I baked!" pics. Since I have the pleasure of living with an adventurous eater now, I'm going to try as many variations using the starter as I can find. Should be fun.

But I STILL want to know what kind of freaky microbes decided to squat in my original starter and have a two-day rave on that miniscule amount of honey I put in out of curiosity. :7

Edited to add a couple more pages from the excellent wildyeastblog:

http://www.wildyeastblog.com/2007/07/13/raising-a-starter/

http://www.wildyeastblog.com/2007/09/29/maintain-starter/

http://www.wildyeastblog.com/2007/12/07/stiff-starter/

[Lucinda]

12. Cool! Thanks for these.

I'm still digging through housewolf's site and will bookmark these to check out too!
We're looking forward to sourdough trials around here. I haven't had good sourdough since I left California. I'm hoping to remedy that!

[Shakespeare]

13. Day 5, and Spongebob is happily doing his sourdough thing.

Probably about halfway to the point where I'll use it to make bread:

[Lucinda]

14. It's gorgeous!

The more you post the braver I get. :)