August 10, 2023 - 9:23am
Looking to build a low PH starter
I'm having trouble souring starter. Leaving it unfed for long periods, 50 100 and 150 percent hydrations, cold and room temp storage and can't get it to move below 5.4 PH. Tried 100 rye, rye with white bread flour and fresh ground ww in varying percentages.
I'm trying to get to about 4 ph or even less
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just.baked,
I've used the following information from our very own Debra Wink to alter my sourdough breads to both high and low levels of sourness (acidity). You can find the full description of the process at the B&T website for parts 1 & 2.
https://brodandtaylor.com/blogs/recipes/make-sourdough-more-sour
Key Factors Influencing Acidity in SourdoughMature when fully risen
Ferment at 70-76°F (21-24°C)
Mature after fully risen
Ferment at 82-85°F (28-29 °C)
Ripe at or before peak rise
Ferment at 70-76°F (21-24°C)
Ripe after peak rise
Ferment at 82-85°F (28-29°C)
Rise to 1½ – 2 times volume
Ferment at 70-76°F (21-24°C)
Rise to 2 ¼ - 3 times volume
Ferment at 82-85°F (28-29°C)
Retard at 40-50°F (4-10°C)
Sources: Debra Wink, Michael Gänzle, Brød & Taylor
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https://brodandtaylor.com/blogs/recipes/make-sourdough-more-or-less-sour-part-2?_pos=1&_sid=8835c6cab&_ss=r
Mother Culture10g whole grain rye flour
Levain25g whole grain rye flour
66g whole wheat flour
48g high-extraction wheat flour
Good luck
Tony
The process calls for "mature culture" (starter?) to make the mother. Should not the levain step call for "mother culture?" It calls for "mature culture," which makes no sense. What's the mother in step 1 for if it is not used is step 2?
It's a little confusing because they add a small amount of the mature culture to the mother culture. The way I understand it is that after a few refreshment cycles, a small amount (30g, in the 'More Sour' column of the Levain, above) is added to the Levain and called Mature Culture in the Levain.
Here's an example:
For me, I have a small amount (60-70grams) of yeast/flour/water as my 'culture' or 'starter' that I store in the refrigerator which I refresh a couple of times before I prepare to make my leaven/levain.
To refresh: I discard 2/3 of the culture's volume, add a new mix of flour/water equal to the amount discarded to refresh and then let it mature. I usually do this 2-3 times and then remove what I need for my leaven/levain.
After I have removed what I need for my leaven/levain I refresh it 1 last time and then refrigerate it.
Note: In the documentation you'll see a nomenclature used to indicate the culture:flour:water ratio, for example 10:50:25. This is a shorthand for the measurement units you are using, i.e. 10 grams culture:50 grams of flour:25 grams of water. This ratio is one of the ways described to make the culture more or less sour.
I hope this helps,
Tony
If Im reading you right, you are not taking 10 g of your refrigerator starter and creating a "mother"
In essence you're mother is the refrigerator starter fed and allowed to rise (double, triple?) a couple of times then 30g of it used to make the levain?
In the "More Sour" example above that is correct.
Here's my routine as an example:
Morning - Mother Culture comes out of the refrigerator and 2/3 of it is discarded. I add the flour/water mix and let it mature for ~8 hrs in the proofer.
Evening - Mother Culture comes out of the proofer and 2/3 of it is discarded. I add the flour/water mix and let it mature for ~8 hrs in the proofer.
Morning - Mother Culture comes out of the proofer and 2/3's is discarded. I add the flour/water mix and let it mature for ~8 hrs in the proofer.
Evening - Mother Culture comes out of the proofer and 1/3 is discarded and ~1/3 is used in the leaven. I add the flour/water mix and it goes back into the refrigerator.
Tony
Do you have any notion of what your mother's ph is after that feeding routine? Seems like fresh flour after more fresh flour and yet more would be reducing the acid, making it less sour. Is the bread you produce turning out sour, moderately sour using this routine? And do you know what the ph of the mother coming out of cold storage is before you begin the feeding routine?
I don't have an acid monitor so I can't tell you the ph level.
I use 100% rye flour in my mother. It's not the acid stored up, it's the ratios of yeast and bacteria in the mother, leaven, and final dough that produce the different acids and hence the sour taste (acidic) vs. yogurt taste (lactic).
Tony
If you leave any starter unfed in the fridge for a couple weeks it will get a lot of acidity. Your yeast will not be strong but you’ll have your ph < 4.
My refrigerator is at 38 F. After three weeks unfed a 100% rye starter is at 5.8 ph
Too cold?
How are you measuring pH?
The pH of white flour is typically in the range of 5.8-6.1. Guessing, I would expect whole rye to be 6.5-7.2.
So the figures you have provided thus far, indicate little if any fermentation.
Can you tell us more about the maintenance of your starter / steps? And when you take pH measurements?
Starter is used once per week, fed after taking what i need and back in the refrigerator. I tried a separate batch left for three weeks with no feed, but acid didkn't rise. PH meter is calibrated and is accurate with a known PH water.
What meter do you have?
A known PH water? What is that exactly?
Calibrated with a one point offset?
I have an HM but resolution was only .5 so got a Yinmik with .1 resolution. After calibratiing in ph solutions I measured the PH of purified water, which i do frequently to verify the meter has not drifted on me. Calibration is done exactly as the manufacturer specifies.
I have a two-year-old 100% hydration all-rye starter that I refresh at 1:10:10 and store in the the fridge. My experience is similar to @jkandell's—my starter is plenty acidic on storage. Levains that I have made with it do become acidic (pH 3.5–4).
I assume you are using a pH meter. Have you checked the performance of the meter to ensure its accuracy? My experience with pH meters (lab career) was that the probes could be fussy with respect to cleaning and storage. I don't have a pH meter at home; I use narrow range pH paper instead.
Besides the actual pH value you are trying to attain, what is your ultimate goal in building a low pH starter?
Is the finished bread not sour enough?
Does it fail to produce the necessary acidity for high% rye doughs?
Looking for more sour. Meter is calibrated and test results in known PH water are correct.
how often are you refreshing?
I refresh on an irregular schedule, on average about every 2 weeks. I have also used unfed starter in some breads.
I find that the sourness of the bread does not necessarily depend my starter. I have made some rye breads that are very sour (Frisian Black Bread, Mountain Oat Bread from The Rye Baker; Oldenburg Rye, Finnish Rye, and Danish Rye from theryebaker-dotcom). Other rye breads (Latgalian Rye from TRB-dotcom) and some wheat (Do-Nothing Sourdough from King Arthur Baking) that have had only a mild sour flavor.
I have been trying to make a San Francisco SD with a strong tang but I have been unable to, despite preparing other tangy breads. I even purchased the recipe for SFSD from Northwest Sourdoughin in my quest. None have worked to my satisfaction.
It is my understanding that the sourness of the bread may depend more on the conditions of the inoculation, bulk fermentation, and proof conditions than the pH/acidity of the starter.
A more advanced test you can try is to determine the total titratable acidity (TTA) of your starter. The TTA will tell you how much total acid is present, not just dissociated acids (H+). TTA also has an impact on the dough and the flavor (sourness) of the bread. You will need a wine acidity kit (link) from the homebrew store and a digital scale. The endpoint can be a little tricky if your starter is dark-colored.
How is the pH meter calibrated and maintained? Do you perform a 1- or 2-point calibration with buffer standards? Is it stored with proper storage solution? I ask only because I know from painful experience (failed chemical manufacturing batch) that a probe that has gone bad is not always apparent.
I am trying to get to a SF level of sourness, from which I figure I can back off once I understand the variables. I'm using three points for calibration of meter - 4 - 7 - 10 PH. After calibration, I test a purified water brand and use the same bottle to periodically check the meter for drifting. I has not moved more than .1 either way since calibrating 4 months ago.
As for acids, I've read two completely opposite takes. One is that it is acidic acid that provides SFSD flavor and others say it is the lactic acid that accounts for it. That's a bummer, because I assume my meter is giving me a PH based on both . If that's the case, isn't the meter reading TTA?
I am to the point where I think getting a starter below 4 ph doesn't matter. I see after building a starter with fresh flour and water for a bake raises the PH, so no matter what the ph of the starter, the process of refreshing/building appears to do nothing but diminish acid.
That leaves the bulk phase to let the yeast start to starve and allow bacteria to get a foothold in my mind. I tried the method of fermenting in the Galal paper but knew something wasn't right with it when it called for a final proof of the loaf for 4 hours at 96 humidity and 105F. Got exactly what I thought I'd get. A balloon with complete gluten breakdown that went flat when handled even gently.
Replicating the flavor of SFSD bread is something I have attempted off-and-on over the past couple of years, to no avail. I even tried the Galal method by proofing directly in the baking vessel. I managed not deflating it, but it had only a hint of sourness. I have also tried a couple of @doughooker’s methods for SFSD but the breads are still not sour enough.
The sour flavor of SFSD is the result of a combination of acids. According to Galal, the main acid is lactic acid, followed by acetic acid and some minor organic acids. Our perception of acetic acid may be more pronounced than lactic acid, but both will elicit a sour taste. However, the pH meter is blind to the source of the acid; the source of the H+ is immaterial. What it measures is essentially the concentration of H+ ions in solution, but not the total quantity of acids (that's where TTA is useful). Here are a couple of TFL threads on sourness:
https://www.thefreshloaf.com/node/43065/sources-sour
https://www.thefreshloaf.com/node/71522/what-makes-rye-sour-function
I would try calibrating the meter again at pH 4 and 7; a 3-point calibration is unnecessary for your requirements, and pH 4 and 7 cover the range you are interested in. Checking the pH of purified water is not a good test of function. Purified or distilled water contains essentially no ions (low ionic strength). Standard pH probes are not designed to measure low ionic strength solutions and the results can be odd. You could also try using narrow-range pH paper (link) to verify the pH. I just smear a little of the levain or dough on the paper and wipe a little to see the color.
This gets a little technical, but acids can be either be dissociated into ions (H+ and an anion) or not. Organic acids like acetic and lactic do not fully dissociate into H+ ions. However, the TTA procedure will measure both H+ and the non-dissociated acids. The endpoint determination (pH 8.4) with your pH meter will be easier than with the included color indicator. Here are some helpful videos on TTA.
https://youtu.be/de0qJIoQMRg
https://youtu.be/sjlxxStd_Nw
https://youtu.be/ZZmwt6Ug-Zg
https://youtu.be/l_8UDwFETZo
have some reading and watching to do.
as for testing meter in water, my thinking is simple (but hopefully not simple minded). Calibrate the meter -take the water reading immediately and then periodically with the same water. Not worried about how accurately the meter is reading the water (ph testing of bottled water is all over the map anyway) but how much variance there is between water readings using the same water and meter. Tells me if the meter is drifting and needs recalibration.
lot of reading and video watching the past week, but so much conflicting info I decided to follow my gut and made progress.
I used my standard 70% hydration 500 g loaf of bread flour, fresh ground hard white and rye, but reduced starter from 20% to 3%
After 10 hrs of bulk ferment at 75 F it had not moved at all. Went to bed and by hour 18 it had tripled. Rested, shaped, and into banneton and directly into 38F fridge for 25 hrs. There was zero rise in the fridge.
Baked and got a bit of spring, very small openings in crumb but main concern was taste. It turned out pleasantly tangy and right where it needs to be for my taste.
I think tripling may have exhausted the yeast. Next test will be shooting for a bulk rise of double (guessing 14-15 hrs at 76F) and loaf right into 38F fridge for 24 hrs. Analyze for taste, rise and crumb and go from there. Want to see some rise in the banneton during cold stage. If not, will likely leave loaf a room temp for an hour before refrigeration on third test, or maybe take it out an hour or two before baking to see if I get some rise.
Trial II method and results:
Same loaf as previous but 14-hour bulk at 75 F to achieve a doubling of dough.
After 24 hrs at 38 F, there was no rise of the dough in banneton. Set it out at 75 F for 2 hrs before baking and got about a 25 percent rise before it went into oven. Photos show the oven spring and crumb, both better than the 18-hr bulk loaf of my first loaf. The 14-hr bulk loaf was less tart than the 18-hr one, but still a bit of tang. Next try will be a bulk stage at a cooler temperature in a wine refrigerator at 50 F untill doubled to see if I can get an acid level a little higher.