Way back in July (7/21 to be precise) Michael Ruhlman posted about a method of kick starting sourdough starter. The method, which he learned from Carri Thurman of Two Sisters Bakery in Homer, Alaska called for the addition of a red cabbage leaf to a mixture of flour and water.
Both Ruhlman and Thurman, as well as several of the former’s readers, reported remarkable results. Yet no one could explain why the cabbage had the reported effects.
Some speculated that the cabbage was loaded with wild yeast, while others (myself included) thought that bacteria might be responsible for the uptick in microbial activity and signs of fermentation (gas bubbles). Since no one could provide a plausible explanation for what might be occurring, I decided to test the idea with a series of tests.
Last night I conducted the first test. The purpose of this particular test was to answer the question “Will adding rinsed and un-rinsed organic red cabbage to a mixture of flour and water make any difference in the rate at which the mixtures ferment?”
Test Design
I made up 7 samples. Each sample contained 20 g of unbleached non-organic bread flour (I wanted as little as possible yeast in the flour) and 50 g of unchlorinated tap water.
- In three of the glasses I put 5 g each of red cabbage that had been rinsed (as per Carri’s method) under luke warm water.
- In three glasses I put 5 g each of red cabbage that had not been rinsed
- In one (Control) glass I put only flour and water
Each sample was mixed with a spoon which was washed with hot water and soap to avoid cross-contamination of the samples. The I left the samples uncovered on the counter in my (68 degree F) kitchen overnight before checking them 13 hours later.
By 7 Am this morning, none of the samples, not even the control have shown any signs of fermentation. Even now (almost 14 hours after mixing) there are no obvious signs of fermentation.
Ruhlman and Thurman suggest that additional flour (a “feeding”) and 48 hours of incubation is required to produce vigorous bubbling. I will let my sample go at least that long before drawing any conclusions. (I will not add more flour.) If after 48 hours, two or more of the samples with cabbage appear to be fermenting more rapidly than the control, I will assume that the cabbage is contributing something to the process and move to the next phase of the testing which will be designed to answer the question
“Will limiting the supply of oxygen have an effect on how the flour cabbage mixture ferments?”
This question is designed to begin to get a handle on what (if any) microbe on the cabbage is responsible for the enhanced fermentation reported by Ruhlman, Thurman and others.
Filed under: bread, cooking techniques, science | 17 Comments »
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