After 47 hours of incubation the samples were all actively fermenting and beginning to show signs of exhaustion of starch supply. All of them had separated into a mat of gaseous foamy starch on top of a layer of relatively clear water and a layer of stringy, insoluble gluten on the bottom.
None of the samples containing rinsed and not-rinsed red cabbage appeared to be bubbling (evidence of the growth and respiration of yeast and bacteria) any more vigorously than any other. And none of the samples with cabbage were bubbling more vigorously than the control made with only flour and water.
All of the samples with cabbage had an “off” odor suggesting the presence of either bacteria or yeast that is either not desirable in bread starter or a desirable form of yeast that had begun to produce a noxious aroma (e.g. butyric acid). By comparison the control smelled like a typical batch of fermenting (proofing) bread dough.
All, except one of the samples with cabbage were slightly more acidic than the control. Cabbage starter samples ranged in pH from 4.5-4.75 with one sample testing at pH 4.90. By contrast the control tested at pH 4.8.
It is still too early in my investigation to draw any conclusions about the efficacy of making sourdough bread starter with cabbage. Nothing that I have seen so far suggests that the method does or does not work. However, the preliminary results of my little test suggest that adding cabbage to the starter may be introducing a microbe that can produce an “off aroma.”
Since so many people have reported that starter made with a cabbage leaf produces great bread, I suspect that at some point during the build, the colony of microbes that is responsible for the “off” smell dies off.
As I wrote above, I’m a long way away from drawing any conclusions. I still don’t know why or how this method works or, for that matter, if it works any better than more traditional ways of building bread starter.
A Hunger Aritist (Redux) 
I have resolved to making the No knead bread, the recipe to which was printed in the NYT about a year or so ago (perhaps longer). I confess I haven't really followed the debate on adding cabbage to a bread starter but I honestly fail to see the point (I also fail my bread starters which puts us at status quo and a classic impasse) with adding cabbage or any other veggie considering regular bread starters will work as well. And I don't mean as done in this (small) test. I have read about leaveners (starters) that use(d) buttermilk. It have been shown though that using old wooden utensils (bowls) that have been used for traditional bread baking with bread starters will help the process since the starter or some of the "particles" will be confined to the wood. I have no idea how this works, just that it does work in and as an early leavener before commercial yeast as such was available.
If you want to add more sourness to a sour bread which is what a starter ultimately produces, there are numerous theories how do best do this. So far I have not seen adding a veggie to the starter would be more efficient than a regular method used for a long time.
If adding a veggie to a starter works for some then it works for some I would, however, be tempted to worry over bacteria.
Bob,
So what makes the starter a sour dough starter as opposed to just a yeast starter? and would the cabbage add any flavor that contributes to the great bread?
– Chris
Chris
I think the assumption on the part of the people who use this method is that the cabbage adds lactic acid producing bacteria something that encourages bacterial growth. But really I don't know.
With or without cabbage in order for the starter to become sour, it has to contain sufficient amounts of lactobacilli.
Finally, the cabbage itself does not seem to impart any flavor to the starter. I suppose if one shredded up a whole head and put it in, it would add lots of cabbage flavor.
I had a quick look at the photographs on the blog.
May I suggest a visit to http://www.strobist.com/ for a quick course in flash photography? Teaching material on the right hand side.
bob, whilst sitting in my fav pizzeria i read in his magazine for the pizza world that people in BC are using grape remnants added to their starter once the winery is done with their pressings. Any input on this?
Natalie
Grape must (remnants) is loaded with yeast and so i think it is fine to add to starter.
What about the temperature of the liquid? When I bake with my baking machine, I heat water to 50° C before I add it so that the dry yeast get activated.
Could it be that warm water with a sour dough starter will get the yeast going sooner?
Tarjei
Absolutley. The microbes in the starter will reproduce faster when the mixture is warm and go dormant at lower temps.