August 9, 2021 - 1:40pm
pH Guided Dough Processing
I chanced upon a new Youtube video by The Bread Code about using a pH meter as an aid to deciding on process step changes in breadmaking.
If this is an area that interests you it might be worth a watch.
Personally, my pH guided breadmaking has not been entirely successful yet. In my last bake I was looking for a pH of 4.4 to end bulk and start shaping. My levain had a pH of 3.85 and intitial dough pH was 5.39, so everything looked good, but I struggled to get to pH 4.40 and only achieved it when the dough had increased in volume by 144%!
I had used 20% levain - next time I'll try 10% to see if that helps.
Lance
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What kind of dough was that? Curious.
Nothing special - 10% whole grain spelt, 5% whole grain rye, rest BF. 75% hydration.
Lance
Thanks! Did you think it was actually overfermented?
I reckon it was!
It didn't help that I did an ambient proof for 1hr 50mins at 25C before retarding to get the pH down to 4.13.
Having said that, the loaf had a good ear and crumb, but lacked height/volume. Flavour was very good.
Lance
Hey Lance, as you know I’ve been using my pH meter and looking at pH. I have the opposite issue really, the loaves reach a low pH before rising as much as I expected. My levains I’ll use around pH 3.9-4.0 and I’m using about 9% or less prefermented flour and most recently made a stiff levain of 60% hydration. The dough pH is also around 5.3-5.4. The pH drops quickly and when the pH was 4.15 the aliquot jar only showed a rise of 25% this is when I shaped. I allowed further bench proofing until the pH dropped to 3.85 which I think is too low. However, Balzslo on IG has some great data on volume increase and pH and he has been experimenting with baking at a pH of as low as 3.6 for 100% bread flour doughs. I generally bulk at warm temperatures of around 82ºF.
Benny
Yes, definitely the opposite problem, Benny! Laszlo seems to indicate a 70% rise for pH 4.30, or thereabouts.
You use a rye starter, don't you - I wonder if this has any bearing? I've got a rye starter on the build at the moment. It was actually built for a different purpose, but I'll be giving it a try soon and will report back with pH and rise results.
I follow Laszlo and his posts are very interesting. I don't know how he gets those amazing volume increases. His loaf specific volume seems to be coming out at about 3.65 ml/g (as best I can calculate as I don't know his loaf weight)). That is a very impressive figure for sourdough.
Lance
Lance
Yes I do have a rye starter, but my levain builds are all quite high ratio, I aim for 1:6:6 or higher so despite rye starters being more acidic there isn't that much of the starter in the levain. I don't know how he is getting those crazy volume increases. I know if I went to such low pH my loaves would be over proofed and flat.
I'll be interested in hearing what you find with your new rye starter.
If you have used a pH meter to check your dough pH during bulk, your results would be welcome. Danny, do you have any data?
Lance
Not on BF. I only kept data on starter ferments. I am IG illiterate. I have tried to learn from Balzslo, but didn’t find enough to go on. I like discussion, not snippets here and there. Too bad for me.
Hi Lance, I made a dough last night.
Consisting of:
11% whole rye
89% strong white flours
12% of which is pre-fermented and composed of strong white flour.
Low-medium hydration: 67%, but slightly soft and slightly tacky, probably due to the rye.
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2 hours after mixing, in the fridge for approx. half-an-hour of that time, pH is 5.34. Core temp is still 26C. Fridge setting 5C
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Next day, 10 hours later.
Immediately after removing from the fridge: pH 5.02, estimated volume increase from eyeballing, about 30% increase from mixed dough. Core temp reads 9.0C (taken about 20 mins after removing from the fridge).
Left at room temp in bowl of tepid water to warm up and reach the desired point for shaping (aka bulk end).
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2.5hrs later. pH = 4.70. Really quite puffy now, getting on for double I'd say.
Another 15 mins later and it's definitely about doubled! ~100% increase.
Shaped immediately. pH = 4.66
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4hrs later.
Dough has grown 2 inches in length, a hair over half an inch in height and just over one inch in width. It is visibly double in volume.
pH 4.36
Baking soon.
Crude dimensions - the dough is not cuboid.
Good info there - it looks like your pHs are going to be more in my range than Benny's (or Laszlo's) - not sure what the differences are. Did you use your LM starter?
I'm doing a retarded bulk tomorrow night (going back to school!), so I'll see what pHs I get.
Your predicted specific volume looks promising.
Lance
Indeed, I did use a LM starter although it has been difficult to get it in shape as of late and ever since making the swap from Marriages to true Italian 00 flour. So it wasn't fully maturo and a little too acidic.
Still my pH readings are yes more in line with yours. With regard to the differences, the first thing that comes to mind is amylase additions with US / Canadian flours.
It would be true that with lower falling numbers we could expect a more rapid increase of TTA.
The finished bread:
Gorgeous loaf Michael. You're probably right that the added amylase likely contributes to the lower pH values that I am seeing with my dough compared to you folks in the UK. The stiff levain I used was 50% sprouted whole wheat and 50% bread flour and used at a pH of 4.09 which is higher than the pH of the 100% hydration levain I usually use. My starter is a whole rye starter which also starts out at a low pH. The dough was shaped at a pH of 4.22 which corresponds to an aliquot jar rise of 40%. The dough was shaped and placed in a banneton and left on the bench until the pH was down to 4.00 corresponding to an aliquot rise of 60% at which time it was placed in the fridge. I'll bake it in the morning and will update then.
Thanks Benny. I was surprised by the bold bloom and very cavernous ear on this bake.
Regarding the influence of amylase on the rate of acid accumulation I can't help but think of durum wheat, which seems to have a reputation for being difficult to bring sourness, and durum wheat is plagued by very high falling numbers, in the 600-700 range.
Un-malted common wheat bread flours might be around 350-450 (hotter and drier climates reach higher numbers)
And typically North American malted flours are around 240.
Great looking loaf with your characteristic round swirl in the crumb!
Was this with Marriages?
Lance
Thanks Lance. Good to know my breads have identifiable characteristics!
Yes, Marriages predominantly.
66% Marriages superfines [15% protein]
11% weak 00 Molino Passini, (W 210)
11% whole organic stoneground rye
12% (PFF) Le5stagioni 00 Manitoba (W 410) [15% protein]
As we know Marriages bread flours are all malted. But I think modestly so compared to North American malted flours.
Working on a loaf today. I made an overnight 60% hydration levain (this is relatively rare for me to do a low hydration levain). At 68ºF 10 hour later about 3.5x rise and pH of 4.09 (1:1 whole wheat:bread flour). Dough mixed pH 5.48 with 9% prefermented flour. I’ll update at the end of bulk.
So this is my steel cut seven grain porridge sprouted whole wheat sourdough.
Bulk fermentation was ended when the dough reached a pH of 4.22 corresponding to an aliquot rise of 40%. After shaping bench proofing continued until a pH of 4.0 was reached corresponding to an aliquot rise of 60%. The dough was cold retarded at 3ºC overnight. In the morning at the time of baking the pH had dropped to 3.89.
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A few weeks ago I did a dual bake. I'm currently keeping a wheat and a rye starter, so I made one loaf with the rye starter and one with the wheat.
I made stiff levains (60% H) and both had a pH of 3.97 prior to use at 10%
The doughs were 10% spelt,3% rye and the rest a BF blend.
I let fermentation run to 86% (rye lev) pH 4.63 and 82% (wheat lev) pH4.66 - so both pHs similar and high.
I did a 1hr ambient proof prior to the fridge retard.
Prior to bake pHs were 4.21 and 4.17, so again, surprisingly close. And both higher than the 4.0 which seems to be the preferred target at bake.
In conclusion, rye and wheat starters gave similar pH results and the results were quite similar to Michaels.
To be continued....
Lance
This is a great thread - Thanks.
I am only just now about to use a pH meter.
I have read fairly widely before going down this route, as well as having a discussion with a Baking Tech. guy with a lifetime of professional work under his belt.
The bread tech. guy made some interesting observations. He said that at different temperatures and acidities different populations of bacteria kick in and 'leave the party' and that though our leavens might be 'stable' there are considerable differences in how each local one might work regarding fermentation and pH.
The other observation, allied to this is that of fermentation temperature and the yeast / LAB balance in our leaven. If the temperature of the leaven's fermentation favoured yeast activity over LAB development then we might reasonably imagine that during Bulk Fermentation we have more CO2 production from the yeast as oppose to lactic acid production from the lower level of LABS. Additionally the BF fermentation temperature will also come into play. Does it favour LAB activity e.g. higher temperatures, or yeast activity, lower temperatures.
I am one of those who is not keen on heavy lactic acid sourness in my bread, but want some of those organic acids to get the aroma development as they react with the alcohol. So, I manage my natural leaven to keep the LAB activity on the low side. So I am quite interested to see what pH's I get.
Any thoughts?
I believe my feeding my starter 100% whole rye was leading my doughs to drop in pH more quickly than what some other bakers were seeing. I’ve taken that same starter and over the spring/summer switched it out to feeding it 100% bread flour. I haven’t been checking pH as often, but when I do I can note that I have a much greater rise in dough volume per drop in pH.
What I conclude from this, wrongly or correctly, is that feeding the starter 100% whole rye gives the starter a greater buffer to acid production allowing the LAB population to grow faster/longer than in an environment with much less of a buffer. Overtime, that seems to leave the starter with a higher LAB:yeast ratio than a starter that is fed only a bran free flour. I feel this is the case because although both LAB and yeast are affected by acidity the LAB are more sensitive to it. So in a starter that has less buffer the acidity climbs more quickly and the LAB would be inhibited sooner than the yeast. Over time the ratio of LAB:yeast in the bran less starter will be reduce compared with a 100% whole rye fed starter. The levains this same starter would create would then start off with less LAB relative to yeast and therefore make levains which has similar proportions. This could explain why my starter is now making breads with a higher rise per change in pH.
Benny
Over time, that seems to leave the starter with a higher LAB:yeast ratio than a starter that is fed only a bran free flour. I feel this is the case because although both LAB and yeast are affected by acidity the LAB are more sensitive to it.
I'm puzzled by this statement because it seems opposite to what happens with salt-fermented pickles. There, as the acidity rises more and more organisms drop out leaving only LAB to continue to multiply and lower the pH. And believe me, that pickling brine can get very acidic. pH values apparently commonly run from 3.2 to 3.5. (I haven't measured the pH of my own pickles, though).
TomP
Hi Tom, as I said I could be incorrect or have some misunderstanding or only partial understanding. I can’t remember who here taught me that the LAB are actually less tolerant of low acidity in comparison to the yeast even though they are the primary producers of acids in our starters.
What I recall them saying is that “ Once pH 3.8 or less LAB stop replication.” But they would still be metabolically active and continue to produce acids.
Yeast are less pH sensitive than the LAB.
I totally understand your point though, LAB are also involved in the natural pickling process and are the main producers of acids converting the sugars to acetic and lactic acid. But perhaps once the pickling liquid reaches that low pH of 3.8 the LAB stop replication and just continue to produce acid driving the pickling liquid lower and lower?
Benny
Hi Benny my understanding is that yeasts generally cease to ferment somewhere between pH 3.8 and 4.0.
The LABS in bread will be completely different varieties from those found in pickling. Yeasts and bacteria like LABs are highly specialised.
Yes LABs are a very heterogenous group of bacteria and the ones in our starters may be different from the ones involved with pickling, but I’d expect there to be some overlap. Regardless, I don’t mean to be argumentative at all, but all I can say based on my reading and discussions with bakers and scientists here is that LAB are more sensitive to low pH than yeast. I wish I could remember who it was who taught me that, I may have been Micheal or Debra Wink.
In broad characterisation, yeasts show strong adaption to a wide range of pH. Wine fermented by yeasts work at a low pH. Grape juice is acidic to begin with; pH 3-4 and Saccharomyces cerevisiae is the most common wine yeast. Going further down the pH ladder we have Kombucha which relies on the presence of yeasts for carbonation. Kombucha ferments down to as low as pH 2.5. In the food industry spoilage concerns for low pH foods such as those that are fruit based and rich in sugar are primarily yeasts and moulds.
The Ganzle paper that was once frequently referenced here on TFL described that the growth of sourdough yeast (C. milleri) was unaffected by pH in the of range 3.5-7. Growth of LAB is however very strongly affected by environmental pH. Sourdough bacteria Frutilactobacillus sanfranciscensis has an optimum pH of 5-5.5 and stops growing at pH 3.8-4.0. Other sourdough LAB can tolerate lower pH levels such as Lactiplantibacillus plantarum min. pH 3.4. As a general characterisation LAB do not grow below pH 3.5, yet yeasts may still do so.
That said, there are always additional factors to consider depending on the composition of the fermenting medium. Measurement of pH is one aspect in its interpretation of acidity however TTA offers a more complete picture by expressing the total amount of acids present. It is possible that at the same pH TTA values can vary widely. Furthermore, the types of acids present can affect the microorganisms differently. Sourdough starter cultures with exceedingly high TTA levels do negatively impact yeasts and LAB may tolerate these extremes better but at this point however the pH would likely be very low.
Your post is so very helpful as I begin my pH measuring project.
I think I will be treating it as a helpful measure rather than a deterministic tool.
Thanks
Kevin
This graph demonstrates that yeast can continue to grow after LAB have shut down, in a sourdough culture. Yeast is shown to be still in exponential growth phase at the point where LAB has stopped growing followed by a decline (death).
I read the graph differently. Both LAB and yeast values level off about where PH levels off, and they don't really change after that (yes, the LAB number drops between the fermentation part of the data and the dough part; but we don't know what is happening between hour 12 and dough mixing time so we can't evaluate what's going on then). I don't know what the units cfu/g mean, though. What's cfu?
What does change a lot is titratable acidity during proofing.
Another thing we can get from the data is that the numbers of LAB and yeast are not in fact growing exponentially at any time. Instead, the fractional rates of increase fall off as fermentation proceeds, and growth is basically non-existent during mix/proofing. The small change in the yeast value from mixing to molding is no more than the natural variation in the readings, and is not enough to support the idea of yeast growth during that time.
There is an anomaly in the yeast value between hours 8 and 10, but if we say that the hour 10 point has a big measurement error, the fractional growth rate of the yeast declines smoothly during fermentation. One would expect this in view of the pH data, I think. (Fractional growth rate is what you want to look at because it accounts for the increase in numbers as time goes on). See graph below:
yeast-fractional-growth.png
TomP
CFU = Colony forming units. Simply, this is representative of the cell count.
0-12 hrs tracks the fermentation of the sourdough starter and the data for that portion is limited to that window. Ideally it would be nice to see everything until it runs its course, but the process studied dictates what is observable. Following this passage, the sourdough starter is incorporated into the final mix and therefore things get diluted and the data shifts.
Over the course of the time elapsed, yeasts can be clearly seen growing steadily all the while LAB have reached a maximum, this occurs over a timeframe of about 4 hours up until the end of the data recorded. Population of yeasts increases significantly all the while LAB are slowly declining!
LAB are the key contributor to acidity so it's no wonder the pH tails off when LAB are shutting down. During 0-12hrs the yeasts are shown to be only increasing in number. No stationary or decline phase is recorded. This is the key point of difference.
I understand your point, but you've taken exponential a bit too literally there! Exponential growth (also called acceleration phase – perhaps more accurately so) is a little more conceptual than mathematically exact because it doesn’t account for environmental pressures in real scenarios. The phases of growth are, lag, exponential (acceleration), stationary, and decline (death). Exponential growth is when the organism shows a continued increase, when this increase declines rapidly and moves toward a plateau, this marks entry into the stationary phase. So your point is invalid.
TTA tends to incline quite linearly in sourdough fermentation up until a maximum.
I hope this helps you to better understand the graph.
Michael
Fleming, H.P., 1984. Developments in cucumber fermentation. Journal of Chemical Technology and Biotechnology. Biotechnology, 34(4), pp.241-252.
I don't disagree, but I recently read - on the subject of salt-fermented pickles - that the yeasts involved are not the yeasts we use in making bread. That leaves it up in the air (for me anyway) how similar the behavior would be.
L. plantarum, a key LAB in both pickles and sourdough bread can be dominant in both environments so it stands to reason yeast could be capable of the same adaption.
Saccharomyces cerevisiae is a ubiquitous fermentative yeast. It can be found associated with fermented grains, pulses, meats, dairy, fruit, vegetables and more. It is key yeast in foods and beverages such as bread, beer, wine, and cheese.
There are numerous types of yeasts and varying clusters of these characterise that medium. While some yeasts show wide adaption others are more niche in the environments in which they grow.
When it comes to pickling vegetables, I would list; the high salt content, the initial low acidity, and a lack of fermentable sugars (that yeast can utilise) as to why LAB dominate the fermentation.
Hi Benny
That's an interesting path to take.
All brans will buffer organic acids in bread dough. I don't know how much though.
I would imagine that the buffering would enable the yeast to continue ferment longer because more hydrogen ions (acid) is held in the buffer.
Of course our pH meters do not register buffered acids. That can only be found by titration.
Heterofermentative LABS, the main players, have a greater tolerance of acids than the yeast.
I looked up some of the research on LABS where different strains were studied. They each had their own signature production of the rate of production of lactic acids and acetic acids. And, though the production of acetic acid was always much less than the lactic acid the ratio between the two varied a lot between the different strains.
I don't know if this is of any help.
Without being able to measure Total Titratable Acids (TTA) we don’t know the total acids in our starters/levains/doughs, I agree. I believe that the LAB are actually more sensitive to the acids they produce than the yeast based on my discussions in the past with various bakers and scientists.
Oh, I don't think you are being argumentative at all. Just asserting fact.
From Francisco Magoya's Fermentology Lecture - Posed her by Albacore - LABs cease activity at about pH 3.4. Well below Yeasts threshold. But that is not the last word.
Anyway I can see from your other posts over the last couple of years that you are well into this. So I shall leave this here. I am fairly well up on the theory, but only just now starting to measure pH in my bread doughs and leavens and you will likely have far more experience. So I shall leave this here.
Measuring TTA shouldn't be too hard, especially if you have a pH meter. I purchased an inexpensive wine-testing kit that included phenolphthalein indicator. I've used this a few times, but I find that the color of the suspension interferes with the endpoint determination. This is especially true with my 100% rye starter.
I had a fair amount of titration experience using indicators in my career as a lab chemist, but the endpoint on the rye starter titration was more difficult than a Fajans tiration endpoint. And if you've ever done one of those, that's saying something!
Thanks for that.
I'm afraid my chemistry falls well short of that. Chuckles.
I've only just bought a pH meter really to see what might be happening in my natural leavens and what the acidity is when I move on from bulk to proofing. I'll use it for my two stage rye leaven too.
If you can? Am I correct is assuming that buffered acids don't affect the Yeast and LAB activity?
Thanks
I'm afraid my biochemistry falls short of that. 🤔😀
In theory, the buffered acids (mainly lactate and acetate) should not affect the LAB and yeast activity because the activity is supposedly governed by the pH. But I imagine high concentrations of these anions may also have an impact on cellular functions.
Also, at low pH, more of the acids are in their undissociated (protonated) state. Because the acids lack charge, they are able to permeate cells more readily and cause stress to the cell.
Hi. Thanks so much for coming back with that.
That is really useful to know.
I've started taking readings now and will just see what I see. At this early stage I am just monitoring acidity not trying to use it as an advisory tool.
Thanks
Kevin
Late coming to the resurrection of my original post! I have to say that I have given up on trying to use pH for bulk endpoint indication. I still monitor pH, but for me, bulk rise percentage is a more useful tool and 40% is the magic figure that I like to use.
My breads tend to end up with a high crumb pH - about 4.3-4.4 - but I don't like sour anyway, so it's not a problem.
Crumb pH is a worthwhile parameter to measure, btw - and very easy to do: 6g bread crumb without crust mushed up in 40g deionised h20 with pestle and mortar and take pH.
Interestingly, my stiff starter seems to now have less gassing power, even though I've always fed it exactly the same way, with the same flour. Who knows why? And in the last bake I used it for, it gave me a crumb pH of 4.08!
So I guess the point I am making, Stonebake, is that I am not sure we can ever call our starters "stable"; there seem to be changes going on, even if we think we are keeping everything exactly the same. And I am definitely one to create a new starter if things aren't going right - sentimental attachment to ailing starters is not a good idea.
Regarding Alcophile's TTA comment, I have just started to do a few TTA measurements for a cautious re-entry to panettone baking. I can provide details of my evolving method, if anyone wants them.
Lance
Hi Lance
Thanks for coming back.
Yes, absolutely. I expressed myself poorly there. Mine is in a stable 'rut' at the moment, but when I change the feed flour, it will change too. I am one of those who keeps their starter in the fridge with no discards. Smell has been my pH meter up to now for that.
Thanks for the pHs for your dough development. Yesterday I took my first readings and the dough was pH 4.5 just prior to baking. A little higher than yours. I too do not like sour bread. I'm very much at the beginning of my practical Ph learning curve. Though already I am thinking I have room to extend my bulk ferment by an hour when not using high percentages of whole meal heritage wheats. (high enzymes and weak gluten).
Over the years I have developed a method to get new starters up and ready to use in 48 hours using freshly milled whole grain flour and a little rye as a booster. All kept at 28C and fed when it wants to be fed rather than a schedule, but then comes the long wait for the LABs to move in. Four weeks? It is then a few more weeks to settle down. So, yes, I don't fix what ain't broke. I think my current starter is only about three or four years old. Though it has a little of its ancestor in there too, but the feed flour changes quite a bit. Stable? Nope.
I won't take you up on the Panettone offer, kind though it is. It's not in my repertoire I'm afraid.
I'll be trying your crumb measurement though. Thanks for sharing that too.
Kevin
I'd be interested to read of your foray into measuring TTA Lance. What kind of numbers are you getting?
Michael
Only done a few measurements so far, Michael.
All as part of my experimentation with Sourbakernz's LMz.
My results so far are:
These are all for LMz1:5/43%, Cu 27% 24hrs 20C
For reference, this is my method for gravimetric, pH endpoint TTA determination: https://docdro.id/mpFEPkq
Lance
Are those repeat measurements on the same dough sample?
Three different refreshes - 2 or 3 days apart.
Beyond the sugar addition, that's a very atypical approach to maintaining the mother. I have reservations about such large feed ratio of 1:5, since this tends to weaken the mother and gear things toward persistent acid development.
Your values are within range however, although I would expect slightly lower pH values respective of the TTA values.
I calculate a Cu of 27% to be about 18% sugar based on your feed ratio and hydration. Is that right?
Current feed 2/10/4.3/1.7z
So Cu I think is 27.3%
In theme with the original post, I noted some pH values for a bake:
All durum wheat for the following:
LM (100% durum): fed .5:1:.45 - after 3hrs @27C yeast was done fermenting. End pH 4.24
Bread formula:
80g LM (20%)
400g flour (100%)
280g water (70%)
8g salt (2%)
Initial pH 5.32
1hr slow mix (RT 18.3C) + 8hrs Bulk (23.5C) - [pH 4.01 @ 7hrs bulk]
Shape (Matera style) + Proof 30 mins. pH before oven = 3.85
A nice looking loaf, Michael. An hour slow mix sounds an interesting technique - was that in the Kenwood?
And some low pHs - was the long bulk because you were looking for volume increase or low pH?
Any sourness?
Lance
Thanks Lance,
Indeed, mixed with the Kenwood - I had to replace the gear system on that recently! Engineering is not my forte, so my dad helped me with that (Good ol' Libra Man he is and of his generation he is).
I posted this to highlight that low pH, as an example of what is possible. On that note, low pH doesn't necessarily mean sour. High TTA is what makes bread sour.
Tasting: no sour on the initial bite and rumination, with a slight acidic, round on the edges of the tongue acid flash.
I went for double volume (100%) to ensure good spring in the oven rather than sour (low pH).
Michael
I remember replacing the gearbox on my old A901 many years ago. A life of mixing 1.5kg bags of wholemeal flour into bread dough had taken its toll.
But it's still going strong and owned by my daughter now!
That's the great thing about Chefs and Majors - they are pretty fixable.
Lance
Hi Mike
Thank you for posting that.
I've made a note of your pH's and will compare them to mine as I collect more data.
My final pH prior to baking seems to be settling at around pH 4.3. I prefer lower lactic acid flavours. Next week I am going to switch from 100% hydration to 60% hydration just to see what gives.
Could you tell me what LM means as a leaven description?
Though your bake is very different to my styles of baking, it brought a smile. A pleasure to see.
Cheers
Kevin
Thanks Kevin,
The interesting thing about lactic acid is it seems that you need quite a high level of it in bread before it becomes noticeable while acetic acid at considerably much lower levels brings that sour flavour.
The intensity of sourness in bread would very much correlate with measurements of TTA but the balance between lactic and acetic significantly alters the quality of that sour as does pH.
Lievito Madre (LM) roughly "mother leaven" in English, really is a catch all term for a sourdough starter which is kept continuously active (i.e., it doesn't get refrigerated to temps below 10C). The term itself doesn't intrinsically mean anything too specific, rather that comes with its context.
In making Panettone for example, there are specific rules about how to maintain it and too there are specifics about how to regenerate the mother used for making the durum wheat breads of Southern Italy.
To me, LM generally means; low hydration (but not always), long ripening times at cool temps when not being prepared for use, short-time refreshes, not allowed to sour / over-ripen, positive oxidation potential, use of additional techniques to modify the fermentation during the long periods (e.g.; binding to trap CO2 or a water bath to moderate acidity and redox potential), low feed ratio (typically), maximised leavening and acidification power.
Hope that helps,
Michael
Hi Mike
Yes, that is helpful.
I use high proportions of whole meal flours. So I expect the buffering is all the greater.
Thanks for the info on LM. I am just about to experiment with lower leaven hydrations, though mine will be more like an old dough / Chef / pate fermente. Except it will be the remains of the leaven just used, refrigerated, rather than from the final dough. A bit odd, I know, but I'm a great believer in keeping things simple if I can. I won't put money on it that I don't end up going down the Italian LM management route. I expect it was developed for a reason.
Then I guess it will be a case of trying higher temperatures to develop the leaven. There are a few different things I want to try. Every now and then something pushes me out of my bread baking rut.
I've now bought a copy of Handbook on Sourdough and Biotechnology.
Thanks for your help. It is really appreciated.
Kevin
I've recently acquired a pH meter (the Hannah) and have been playing around with it. I am also experiencing rather high pH values for my doughs. Here is a recent bake where i decided to follow the pH meter instead of visual cues:
stiff starter at 50% hydration fed at 1:1 flour:starter and left to ferment 5hrs at 28-30*C. pH at inclusion in the dough 4-4.1 so young levain stage.
dough: 80% roller milled med strength flour, 10% wholemeal rye, 10% wholemeal wheat; 80% hydration, 15% stiff starter (9% prefermented flour), 2% salt.
pH at end of mix was 5.6. FDT 24-25*C. bulked until a pH of 4.2-4.3 which required 100-150% volume increase of the dough and took around 5hrs. much more than I usually would.
preshaped, shaped and retarded for 16h at 4*C. pH before the fridge was 4.1-4.2. pH at the time of baking was 3.8-3.9
i wasn't too happy with the results. the crumb wasn't particularly open due to high inflation of the dough when shaping so many of the alveoli had collapsed. it's a bit gummy and too moist for my liking.
I am doing the same recipe today but with a starter refreshed at 1:0.5:0.3 (30g flour, 15g water, 10g starter) at 20-22*C room temperature for 16h. the pH before inclusion was 3.9. FDT 25-26*C and pH 5.5-5.6. the dough is acidifying quite slowly and 3.5hrs into bulk the pH was 4.6-4.7 with the dough having increased in volume 50-100%. i preshaped, shaped and put in the fridge with a pH before it going in there at around 4.4
I'm thinking that my starter is low in lactic acid bacteria and high in yeasts. My doughs seem to be gaining a lot of volume fast - I had an aliquot jar for this bake and I saw a 100% increase for the 3.5hrs of bulk time at 25-6*C. This does seem a bit fast, no? I would ideally like to shape earlier as the dough was again very inflated and I had to be extra careful when shaping. I use a mixer and develop the dough before bulk to a large extent so I wouldn't be suffering any dough strength. And I could do a warm proof before retarding. The acidification would of course continue no matter if the dough is in "bulk fermentation" or "proof". I just wonder whether I am losing out on flavor by running high pH. And, you know, just wondering whether that's just a specific state of my starter and if I could control it by changing the feeding regime. I've been doing low inoculation feeds (10-25% prefermented flour twice a day, 20-22*C ambient temp) lately which might be the reason?
P.S. I calibrated the pH meter 2-3 days ago and have done 30ish readings since. hopefully it hasn't drifted much
edit: I just revisited Sourdough Baking by TTC and 4.5-4.7 is given as a range at which bulk fermentation should be ended so it seems like the pH values I'm observing more or less fall within what is expected
This sounds similar to my situation. Have you seen my recent follow up post regarding fortified flours?
And where are you based? (Best to fill in some info in your profile, so others know.) Are you using fortified flours? Like you, I could only get the pHs others quote, eg 4.1, by having a high percentage rise bulk, eg 100%. Funnily enough a lot of bakers absolutely love that sort of rise, but for me, the dough is past its best and gives low loft and poor ears and crumb.
So I go for 35-50% and accept the higher pH. I am still investigating my calcium carbonate fortification theory, but it is now made more difficult because you simply can't buy non-fortified non-wholemeal wheat flour in the UK now - not even imported flour, following a recent government rule change.
Regarding starter, I too use a stiff 50% hydration starter, but I keep it in the fridge, feeding weekly. I feed it at 1:2 - I don't think higher ratios are so good. I used to refresh at 25C, but now I use 28C, to encourage the lactics. I have also tried a 130% starter without much difference in pH results.
Lance
I think it's not the amount of rise per se, but the length of time that fermentation has been going on.
They would include me, mainly because I think that the longer the fermentation time (and for that matter, the longer the dough is hydrated), the better the taste. Of course, it depends on what you think a good crumb should be. My loaves usually have a fairly uniform texture without many large cavities. The pores may be large (high hydration, for example) or smaller (e.g., low hydration or more whole grains).
I don't actually care for a lot of large cavities. I think they lead to a dried-out mouth feel and taste, and the breads stale more quickly. Of course there are always exceptions. Also, I would like to be able to produce large irregular cavities if I want to, but I've not been so good at that.
I've been thinking it's past time that I experimented with much shorter bulk ferment periods, and maybe now is the time.
TomP
Agreed. I consider large holes/cavities a failure, and to be avoided. The only possible advantage I see in them is, they hold an extraordinary amount of butter :)
Well, there are large irregular cavities as in a fine baguette, and then there are loaves filled with big mouse tunnels. Not the same at all.
but will remember than should it happen :)
Please let's not descend into another "anti-open crumb" discussion.
Tom I agree about length of bulk. I guess within certain limits a longer bulk is likely to give better flavour and this can be achieved by a lower temperature or reduced levain dose. It's just that for me, a bulk of 3- 4 hours fits in better with non-baking life.
Do let us know how you get on with a reduced bulk rise percentage trial, ideally with pHs monitored - levain, dough start and dough finish. Though personally I am a big fan of doing a bread crumb pH the day after baking rather than drilling holes in a loaf prior to baking (plus I easily forget to do it!).
Simply take 3g of crumb without crust and mush up with 20g DI water, ideally with pestle and mortar and take the pH.
Edit: sorry I should have defined my pH sampling points more clearly:
Lance
Definitely not! It's just a matter of personal preference, anyway.
As to pH measurements, I'm just getting my feet wet. I haven't tried measuring the pH of a baked loaf. I'm not sure what guidance that would even be giving me.
I haven't tried measuring the pH of a baked loaf. I'm not sure what guidance that would even be giving me.
It's just an easy alternative to doing a pH just prior to baking. I don't think there will be much difference between the two results.
I don't think flour is fortified here (Bulgaria).
It is interesting that the pH values given by the YT guy and the ones given in the TTC sourdough book differ significantly with mine and yours falling within the range suggested by the latter.
edit: ah, i thought i added an edit in my previous comment with a discovery i made just a bit after posting it but it seems like i didn't hit save or something. so, after writing the comment i opened TTC's Sourdough Baking book and saw that the pH range suggested for end of bulk/start of proofing are 4.5-4.7 and those for end of proof 4.0-4.2 which is more or less what we're seeing. of course, if one goes for a lower hydration loaf which is degassed once or twice before shaping, similar to a yeasted loaf, i would expect lower pH values but for the style of bread we're aiming for, this seems to be the norm.
Bronc, I don't have any of Thomas Teffri-Chambelland's books, so I can't really comment on what he is saying regarding pH drops.
Lance
Hello, Advanced laboratory PH reading section partisapents.
I have neither the expertise, or the Patience to follow this exercise closely. I am curious and hopeful of a resulting chart or another form of guidance that would accurately predict the percentage of rise/fermentation. If such a outcome is achieved I would be an early adapter in using the new, exciting, ground breaking method.
Albacore.
I have an idea you could bring to shark tank.
A PH meter the reads in a scale of % fermentation, along with the standard PH scale. An artisan bread for dummies tool if you will.
Good luck
Will Falzon
I like your idea Will - the Magic Meter! Don't expect it anytime soon though, because every baker has a different idea on when stage x or stage y in the breadmaking process is "done" - even the actual baking!
Still, we don't want all loaves to look and taste the same, do we?
Lance
Regarding loaves all looking the same. We still would have the choice of prolonging or cutting short the fermentation. Only now we would have definitive information to guide us. Well, that is the goal anyway.
PS
I would be so excited to be able to tell my great grandchildren on my death bed that I helped inspire this ground breaking development in the art of bread making. Combining science and art what a dream!
LOL
I kill me!