The Fresh Loaf

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Inquiring Minds Must Know!! Can Blueberry Yeast Water be Pushed to the Limit?

breadbythecreek's picture
breadbythecreek

Inquiring Minds Must Know!! Can Blueberry Yeast Water be Pushed to the Limit?

The question I had is what would happen if you fed a Blueberry Yeast Water/Bread Flour levain additional Blueberry Yeast water, using seeds from previous levain builds.  Namely, what is the effect of increasing population of blueberry yeast over a series of builds while holding the overall volume constant.  Would there be an improvement or degradation in rise times or volumes?  Would there emerge a limit as to how quickly a doubling or peaking would occur?  Would it explode into a new black hole? These were the questions that I just had to answer for myself.

Methodology

I started with 10g blueberry yeast water (BYW) and 10g Bread Flour (BF). This was left to rise to its maximum height and plateau, whereupon it was chilled for the night.  The next morning 7 grams of this levain was fed 7g BYW and BF, and again left to rise to it’s maximum height and plateau, then chilled or refreshed.  Using time-lapse photography (thank you RonRay), I was able to track the level of growth for each build on 15- minute intervals. I intended to continue this refreshment pattern and observe the action until the growth/plateau cycle was found to closely resemble the previous builds or something else happened to draw my attention away. 

 Findings

 The following graph shows the results. 

 

Just looking at the doubling times, clearly the more iterations of builds shortens the time required for the levain to double.  R1 took almost 7 hours to double, whereas R2 took 5 hours, and R3 took 2.5.  Most of the trials R3-R7 in this 2-2.5 hour range to double. By far the fastest doubler was R8, at just 1.5 hours.

There is also interesting phenomena with respect to the period of growth before plateauing.  R1 took about three hours take off, presumably adjusting to the new food/environment, and didn't fall off until almost 8 hours after the first feed (5 hours of active growth).  R2 took an hour get going, but fell off an hour quicker than R1, (six hours of active growth.  R3 didn't lag at all. It grew from the time that it was fed and continued steadily for almost 6 hours.  R4-R6 all took off from the get-go, and enjoyed a solid 4-4.5 hour growth stage before plateauing.  The standouts were R7 and R8, which both not only took off from the start, but also, grew for an astonishing 6 hours before exhaustion.  So something about more yeast in the culture allowed for a longer growth stage, despite a finite and constant supply of food.

The peak volumes also varied with the yeast concentrations.  The lowest amount of yeast, R1 was barely able to double (2.3X) before giving up.  R2 was slightly better at 2.5X. R3 and R4 made it just to 3X. R5 and R6 got to 3.5X, but again, look at R7 and R8. They got to an impressive 4X! It took them a long time, but they never lagged, they just kept going, and going and going.

From a temperature perspective, there is apparently an outside, uncontrolled effect.  As we can see, the cycles R3-R8 closely track each other.  The cycles of R7 is very similar to R5, both of which were started first in the day, from seed chilled overnight in the refrigerator.  R8 proves to track closely with R6, indicating a typical afternoon pattern. So there may be a distinct positive effect from room temperature (it gets hot in the afternoon here now (86*F+).

In conclusion, I believe a YW builds should be fed subsequent builds with more active YW until a doubling can be achieved within about 2 hours and the capacity of growth is around 3x or more, usually by the third build.  Given the time and desire for even stronger levains, subsequent builds using active yeast waters will not have a detrimental effect on your doughs, although some care should be taken to avoid overproofing.

An aside... In a separate experiment, I discovered that this Blueberry Yeast Water is the least effective of my collection, bested by far by the Cherry Yeast Water.  I intend to repeat this analysis using the Cherry Yeast Water instead.

Again Stay Tuned...

-Pamela

Comments

RonRay's picture
RonRay

Pamela, your plot even looks familiar.  As you concluded, these repetitions clearly show improvement in the rate of rise with successive back slopes. If I understand your procedure, each day's test batch consisted of a portion of the previous day's test batch and a refreshment of 50/50 BYW & B/F.  Thus, each day the WBBs in the test culture seem to selectively be more inclined to consume the fresh BYW & B/F  that served as their refreshment. Your data certainly supports this.

Another way to state this might be to say that you are generating a new culture, not of 'stronger' BYW, nor of 'weaker' Bread flour WBBs, but of a different Hybrid WBBs sourdough that tolerates blueberry in their water.

I am NOT saying that is the case - I have no idea if this new levain gets the sour of SD, or maintains the sweetness of the BYW, but what I am suggesting is there is no way to tell the difference in this method, without some independent method of checking what is going on at the WBB level.  Other than taste-testing for a sourdough flavor having entered into the breads used with this levain, the only thing I can think of would be a the microscopic or DNA levels.

I hope I made made it clear what I find confusing, or I guess 'unclear', would be a better way to say it. However, I think your experiment is very interesting, and am pleased to see it posted.

Ron

breadbythecreek's picture
breadbythecreek

Hi Ron, I concede that you are the "godfather" of these experiments. Thank you for your insight on procedures and methodology. 

To restate my objective: I wanted to see if there would be an effect (beneficial, detrimental or nul) of ever increasing proportion of yeast on a finite food source using successive builds of bread flour and BYW.   Although I am not able to say what yeast is surviving, BYW, BF or some hybrid, but, I can definitively say that the blueberry loaf made with hungry R4 was not in the least sour. It was excellent both with cream cheese for breakfast and brie for dinner.  

BTW, the cherry test trial #1 is taking off like a shot!

-Pamela

RonRay's picture
RonRay

Pamela, no way I am any kind of "godfather" ROFL

I tried the same type of back sloping with Apple YW. It was only after the 6th build (each of 24 hours) that the sour started to come in. Of course, that was a different set of conditions and a different YW and a different flour (A-P F). And one point on the line,  a trend does not make ;-)

Keep experimenting and posting the data - I think there is far too little of that done !  And praise you for doing it (^_^)

Ron

Frequent Flyer's picture
Frequent Flyer

I assume that R1 was the initial refreshment on day 1 and R8 was the eighth refreshment on day 8 and that each refreshment was 7 g of yeast water and 7 g of bread flour.  Is that right? 

If you were to use R8 to make bread after it was in the fridge for a week, how would you refresh it?

FF

breadbythecreek's picture
breadbythecreek

Hi FF, thanks for reading this long post. It was a fun experiment and quite puzzling. Like how could the final runs exhibit such sustained and voluminous growth using the same amount of food as the others?

R1 was the initial mixture of blueberry yeast water (10g) and bread flour (10g).  The second, third, fourth...eighth consisted of 7g of the previous number's culture as seed and fed 7g BYW and bread flour (tossing out 1g to make up for the overage and keeping the volume the same). As a note, these builds were done consecutively, not simultaneously, and as close together as possible, but allowing for rests overnight (some of the faster runs happened in the AM and PM of the same day), so it didn't take eight days to run the entire experiment.  

You are asking, what if I were to hold onto R8 after it had finished it's cycle (I didn't; I tossed it), and refrigerate it for a week then use it to bake bread?  Well, I guess I'd take it out, let it warm up a bit (it's hot here so maybe 30 minutes, then feed it enough flour and BYW to equal the amount in my recipe (say ~75g).  I take all 20gs, not just 7g, and feed it 28g flour and BYW, let that double (not letting it get to it's full potential height), then finish the recipe.  

I'd treat it just like any other starter.  It may cause my final dough to rise faster, so I'd have to keep a better eye on it to avoid overproofing.

Did I answer your question or am I still misunderstanding? Please let me know.

-Pamela

Frequent Flyer's picture
Frequent Flyer

Thanks.

FF

nova's picture
nova

All,

Pamela's experiment pushing the feeds sequentially was exquisite ( I was a environmentsl Tox researcher for 7 yrs)....Ron has heard from me, since I confided to him I have become gluten intolerant....but I am so fascinated by the Fruit yeast waters and how they could be used in a gluten-free mode, allowing for still using wild yeast fermentation of non gluten flours.  Keep posting your excursions into this alternate universe of fermentation....Great Stuff!

nova

breadbythecreek's picture
breadbythecreek

For taking the time to read about this stuff.  I am purely an amateur. Hubby was trained as a molecular biologist and I spent a lot of my youth waiting for him in the lab while he worked at the bench. I guess after all these years since he left the bench, it's finally coming out in me.  What cheaper hobby but flour and water? Great fun.

-Pamela