I'd say, this is a potential measuring error asking for attention.

How often did you do the test or do you have some soap left in the
container which dissolves after a while?

What is the pH of the flours you use? That would be your baseline and
when you add some acid with the starters, it would go down.
That would be an interesting number to see the effect of 10 % of starter.

One effect may be happening. If you grow one starter on a particular
flour and then on another flour, there may be a higher time of
"retooling" used by the critters to adjust to the new goodies.


I was measuring SD pH's until it got too boring and never saw anything
like it - pH increasing after starter was mixed.

Sam

Doc wrote:
> Just some food for thought. I ran an experiment comparing the pH of
> two samples of the same starter refreshed with different flours. Both
> samples consisted of 10g of starter + 50g water + 50g flour. Both ran
> at the same temperature (75°F to 78°F). One was made with fresh
> ground whole wheat flour, the other was made with enriched, bleached
> high gluten white flour. I think this demonstrates the phenomena of
> whole grain flour buffering the starter and allowing the accumulation
> of more total acid before the LAB growth shuts down at a pH below 4.0.
> The most interesting result is the increase in pH during the first
> hour. Anybody care to speculate on why this happens?
>
> Look here for data:
> http://picasaweb.google.com/DocDough/StarterPH/photo?authkey=W5xf8wUEzog#5217143234399849442"><im gsrc="http://lh5.ggpht.com/DocDough/SGcEIUy8S-I/AAAAAAAABEI/OoT2ArgoJQs/s144/Starter%20pH.jpg
>
> Doc
>
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