Author Topic: Ischia Acetic/Lactic control with temperature  (Read 3700 times)

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Offline s00da

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Ischia Acetic/Lactic control with temperature
« on: September 23, 2009, 05:00:41 PM »
The first thing that came up to my mind when I got this nice temperature logger http://www.pizzamaking.com/forum/index.php/topic,9285.0.html is to experiment with Ischia and try to understand the effects of fermentation temperature on acetic and lactic acid production because I was having problems with my baguette recipe producing a tight closed crumb even though it was 66% hydration. My baguettes always turned very leathery and only edible within 2 hours from bake time.

In my baguette recipe I was fermenting the dough for 24 hours @68 F and that produced a leathery baguette but I liked the sourness. I was suspecting that the acetic acid produced caused the problem because during shaping, the dough had this swollen kind of feel to it and doesn't feel sticky or extensible at all. I attempted the same recipe for 20 hours fermentation @70 F and the result was not very different.

When I increased the fermentation temperature to 73.8 F, the dough needed only 15 hours to reach the same expansion. During shaping, the dough was nicely extensible and very friendly shaping into baguettes. They baked nicely and the crumb was superb comparing it to the previous tight, toast-like crumb. They are not leathery anymore but the sourness is almost gone.

I might attempt the dough again and ferment at 72 F but it seems that the acetic acid production for the Ischia was high at 70 F and less where the gluten strengthening effect was very obvious. I underestimated the strengthening effect of the Ischia, never thought it would be that dramatic. I think now I understand the reason that sourdough bread is made with stages because if you make it in one stage and try to produce the sour, you will basically be making a big biga!

Saad


Offline andreguidon

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Re: Ischia Acetic/Lactic control with temperature
« Reply #1 on: September 23, 2009, 05:15:21 PM »
Nice Research Saad !!! ill be activating my italian starters soon, i use a SF one that i like allot....
"Simplicity is the ultimate sophistication." Leonardo da Vinci

Offline s00da

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Re: Ischia Acetic/Lactic control with temperature
« Reply #2 on: September 23, 2009, 06:26:36 PM »
Thanks andreguidon. When using the Ischia for pizza dough, just remember to go with a temperature of 73.8-75F. I will be trying the 72 F soon and will let you know of the outcome. What would be interesting is decreasing the temperature back to 68-70 and increase starter amount in the recipe to shorten the fermentation time. I wonder if the gluten will be strengthened...Nonetheless, it seems that my finding is in-line with what other members are doing with the Ischia.

Saad

Offline UnConundrum

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Re: Ischia Acetic/Lactic control with temperature
« Reply #3 on: September 23, 2009, 09:03:50 PM »
Saad, the crumb on your baguettes looks great :)  I was always told that the "ying/yang" of sourdough was that the bacteria loves the cold and the yeast loves the warm.  You make the bread more sour by fermenting longer and cooler, giving the bacteria time to work.   If you want less of a sour taste, go warmer to allow the yeast to work "overtime."  I'm not really following your thoughts on this affecting the gluten development.  I've been trying to get my head around your other posts and it's just not clicking for me.  My reaction to your tight crumb would be to just give the yeast more time to work.  Please correct me, but I believe you're saying that the longer fermentation causes the gluten to develop more strongly and that it tightly holds the water in smaller quantities, thereby creating smaller pockets of steam when the bread bakes.  While, if true, it would make sense, I'm just not buying in yet.  I know (and use the fact in my own baking) that gluten develops over time;  I just wouldn't anticipate the time/temperature changes you're observing having that affect on the gluten.  Wish there was some other (reasonably priced) tool to measure gluten development.

Offline s00da

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Re: Ischia Acetic/Lactic control with temperature
« Reply #4 on: September 23, 2009, 10:28:28 PM »
Thanks for jumping in UnConundrum. In my post I wasn't referring to gluten development in the notion of having it absorb more water or tightening it by performing stretch and fold method for example as such methods account as part of the mechanical or organic development of the gluten. I was referring to gluten strengthening caused by the effects of acetic acid.

When using sourdough starters, it is known as you mentioned that fermenting at lower temperatures will produce more sour and that is because of the greater acetic acid production at that temperature. It also happens that acetic acid strengthens the gluten in a different way that I wish I can understand (I tried  ;D) but for the sake of an explaining it, consider the biga. While the biga is made using commercial yeast, it's basically used to give this certain type of gluten strengthening. The biga will give a final product that is more chewy than if you use the direct method or if you use a poolish. The reason is because fermenting in a dryer environment like a biga is known to produce more acetic acid which gives this strength to produce a chewier crust/crumb. This is also the reason why some sourdough bread makers keep their cultures in dry form (50% hydration) in addition to fermenting in colder temperatures.

Consider the difference between the two doughs I made; one fermenting for 20 hours @70 and the other for 15 hours @73.8 F. The temperature difference is very small and both achieved the same expansion so I don't think yeast hasn't been allowed to work. Add to that, that both doughs after shaping were allowed to proof at 75 F for 3 hours before baking, so there was more time for the yeast. The 70 F dough was different in a very dramatic way that I don't think it's just a matter of allowing it to ferment; thus I contribute the difference to the acetic acid production.

Saad
« Last Edit: September 23, 2009, 10:30:33 PM by s00da »

Offline UnConundrum

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Re: Ischia Acetic/Lactic control with temperature
« Reply #5 on: September 23, 2009, 10:59:23 PM »
Quote
It also happens that acetic acid strengthens the gluten i

Most of the scientific stuff on the web dealing with gluten and acetic acid is way over my humble head, but what I do see is several comments that acetic acid dissolves gluten (whereas water does not).  It would appear to me that something that dissolves a substance doesn't also make that substance stronger. 

That said, your observations are pretty tuff to explain.  I don't know if you're able, but I'd suggest you make one double sized dough, divide it and treat each half differently, just to rule out any small difference in formulation affecting your results.

Offline scott r

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Re: Ischia Acetic/Lactic control with temperature
« Reply #6 on: September 24, 2009, 12:26:05 AM »
treating each half differently is great advice.   I honestly think that unless you are feeding your starter the same amount at the same times every day for a few months and not putting it in the fridge, you are going to have different conclusions based on how acidic/active your starter is at any given time.   The only times I have seen starters behave perfectly consistent day to day are in bakeries where the conditions are just as I specified above.   THis is a great experiment, and you should keep experimenting, but I think if you do this one a number of times you might get a number of different results.   
« Last Edit: September 24, 2009, 08:33:16 AM by scott r »

Offline s00da

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Re: Ischia Acetic/Lactic control with temperature
« Reply #7 on: September 24, 2009, 04:01:39 AM »
Most of the scientific stuff on the web dealing with gluten and acetic acid is way over my humble head, but what I do see is several comments that acetic acid dissolves gluten (whereas water does not).  It would appear to me that something that dissolves a substance doesn't also make that substance stronger. 

That said, your observations are pretty tuff to explain.  I don't know if you're able, but I'd suggest you make one double sized dough, divide it and treat each half differently, just to rule out any small difference in formulation affecting your results.


Acetic acid destroys gluten when it's produced in excess and a certain pH level is reached but before that stage, is has a strengthening effect. As you can see from the following posts, this is an already established fact that is actually in-use by artisan bakers so they're not really my observations. I just happen to stumble upon them when I wanted to make more sour in my baguettes.

http://www.pizzamaking.com/forum/index.php/topic,8093.msg80312.html#msg80312
http://www.pizzamaking.com/forum/index.php/topic,8093.msg80399.html#msg80399

I can of course, split a dough in halves and ferment at different temperatures but it really serves no purpose since I measure everything that goes into my recipe. I'm really talking about a big difference between the two doughs that can only be made by a big mistake in measuring the amount of water that went into the recipe and I highly doubt it.

Saad

Offline s00da

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Re: Ischia Acetic/Lactic control with temperature
« Reply #8 on: September 24, 2009, 04:16:43 AM »
thats great advice.   I honestly think that unless you are feeding your starter the same amount at the same times every day for a few months and not putting it in the fridge, you are going to have different conclusions based on how acidic/active your starter is at any given time.   The only times I have seen starters behave perfectly consistent day to day are in bakeries where the conditions are just as I specified above.   THis is a great experiment, and you should keep experimenting, but I think if you do this one a number of times you might get a number of different results.   

scott, you're totally correct regarding the maintenance of the culture. I'm basically using my Ischia according to Dr. Ed Wood's directions in his book: Feed - feed again if culture isn't fully active within 3.5-4 hours - use - store portion in the fridge and I'm very happy with the results being pretty much consistent. For my neapolitan pizza, things have been the same for the past 6 months and I use the starter twice a week. The baguettes are the new comer and it's too soon to say I'm consistent in this field.

Nonetheless, at each use the Ischia is certainly different but it could be a slight difference that I'm not noticing.

Saad

Offline scott r

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Re: Ischia Acetic/Lactic control with temperature
« Reply #9 on: September 24, 2009, 08:03:54 AM »
twice a week is good, that is much more often than most home bakers, so you should be showing more consistent results than many of us.   Still, I think its important, just as it is with your kneading experiment, to do the same test a bunch of times to make sure your conclusions are correct.   There are so many variables, and adding in a culture to the mix (even a perfectly "activated" or multiple fed one) introduces many many more variables that can change from day to day.   Good luck, and please keep up the experimenting, I am enjoying these posts!
« Last Edit: September 24, 2009, 08:36:09 AM by scott r »


Offline s00da

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Re: Ischia Acetic/Lactic control with temperature
« Reply #10 on: September 24, 2009, 08:17:32 AM »
I don't know if the Ischia is more forgiving than other starters but when I go without using it for more than a week, I usually require 2 feedings to get it back to fully active. Once I went for a whole month and still all it needed is 2 feedings. Another time, I had a bad bag of flour that had more than usual bran and it gave an off smell to the Ischia. All that I needed to fix it is a whole day feedings every 3 hours and all is good.

Offline Bill/SFNM

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Re: Ischia Acetic/Lactic control with temperature
« Reply #11 on: September 24, 2009, 04:22:03 PM »
I usually require 2 feedings to get it back to fully active.
Saad,

What are you using to determine that your culture is fully active? Bubbles/foaming and expansion are cues for yeast activity, but may not be an indicator for the state of other microbes that be important for flavor. In my less scientific tests, a frequently fed culture with a single feeding will have a different flavor profile than a more neglected one with multiple feedings. For most of my cultures and most of the breads I make, I prefer the results from frequent feedings, so I rotate through them as regularly as I can. One thing from Ed Wood's procedure that makes a big difference is to ensure as active a population as possible before putting the culture away in the refrigerator; I give it a final feeding and let it sit @ 70F for an hour before putting it away.






Offline s00da

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Re: Ischia Acetic/Lactic control with temperature
« Reply #12 on: September 24, 2009, 04:43:05 PM »
Saad,

What are you using to determine that your culture is fully active? Bubbles/foaming and expansion are cues for yeast activity, but may not be an indicator for the state of other microbes that be important for flavor. In my less scientific tests, a frequently fed culture with a single feeding will have a different flavor profile than a more neglected one with multiple feedings. For most of my cultures and most of the breads I make, I prefer the results from frequent feedings, so I rotate through them as regularly as I can. One thing from Ed Wood's procedure that makes a big difference is to ensure as active a population as possible before putting the culture away in the refrigerator; I give it a final feeding and let it sit @ 70F for an hour before putting it away.


Bill, I got the Italian starters but I only activated the Ischia. I use expansion as my indicating along with smell. I look for double+ expansion in a glass jar.I also smell the Ischia each time before I use it to familiarize myself and I think it works. I have kept my feeding procedure fixed to better understand the Ischia:

1- 650g kept in the fridge
2- I activate it by feeding 150g water + 150g flour for a total mixture of 950g which is exactly half of the glass jar that I use
3- When in normal conditions, it doubles in 3 1/2 to 4 hours. If that didn't happen, I feed it again. Usually it works on the second feed. When I did the whole day feed, I fed it back to back each time it doubles and it seems that it cannot double in less than 3 hours.
4- When fully active, I put the initial 650g back in the fridge, take what I need and discard the rest.

Since you're here  ;D I know you ferment your Ischia dough at 75 F (please correct me), have you tried lower temperatures like I have? and were there any differences?

Saad

Infoodel

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Re: Ischia Acetic/Lactic control with temperature
« Reply #13 on: September 24, 2009, 04:47:52 PM »
I don't know if the Ischia is more forgiving than other starters but when I go without using it for more than a week, I usually require 2 feedings to get it back to fully active. Once I went for a whole month and still all it needed is 2 feedings. Another time, I had a bad bag of flour that had more than usual bran and it gave an off smell to the Ischia. All that I needed to fix it is a whole day feedings every 3 hours and all is good.

I know the feeling re: bad flour (usually wholegrain flour gone rancid) is terrible. I have a 55 pound bag of whole rye sitting in the kitchen atm which is next to useless. It was only recently delivered - needless to say I was not impressed!

Toby


« Last Edit: September 24, 2009, 04:49:57 PM by Infoodel »

Offline Bill/SFNM

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Re: Ischia Acetic/Lactic control with temperature
« Reply #14 on: September 24, 2009, 04:57:23 PM »
Saad,

Over the past several years I have tried all kinds of combinations of temps, times, ratios, nudging ever-closer to the method I now use which includes 70F for fermenting and 75F for proofing for 24-hour Ischia pizza doughs. I am using the ThermoKool with an error of +/-5F; a higher level of precision hasn't seemed necessary since I can achieve very consistent results - this dough seems pretty forgiving of minor variations in temp and time. Handling and baking temp/time seem most critical and I have been keeping the other steps constant as I try to improve my skills in this area. I will add two related observations that I have made previously:

1. When performing this kind of exhaustive testing, it was frequently the case that I would change a time or temp, observe the results, and make a conclusion of that particular parameter's role in the whole process only to discover that the next batch contradicted those results. After backtracking and rerunning tests, it often turned out that the results I observed had nothing to do with the parameter I changed. As mentioned above, handling and baking time/temp trump everything else.

2. After baking hundreds of pies, my preferences evolved. Conclusions about what tasted better a year ago are no longer valid.    

Infoodel

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Re: Ischia Acetic/Lactic control with temperature
« Reply #15 on: September 24, 2009, 05:10:20 PM »
"1. When performing this kind of exhaustive testing, it was frequently the case that I would change a time or temp, observe the results, and make a conclusion of that particular parameter's role in the whole process only to discover that the next batch contradicted those results. After backtracking and rerunning tests, it often turned out that the results I observed had nothing to do with the parameter I changed. As mentioned above, handling and baking time/temp trump everything else."

Agreed. Trying to isolate parameters for specific effects can get confusing when it comes to sourdough cultures. The very same bacteria in a culture can ferment along different metabolic pathways under different conditions (temperature, hydration, substrate etc.)  It's possible to predict the outcome IF you know exactly what bacteria are present in your culture but the more pragmatic approach is simply to get  familiar with the culture over time and with experience.
Regardless of the provenance, it is possible to get a wide range of results from just the one culture. I'm not one who is at all precious about cultures. I'll happily start a new one if my carelessness has resulted in the weakening of a culture. I used to maintain 5 or 6 at a time - but now it's just the two. From flour & water to fully active starter only takes about a week  - I can wait that long :)

Toby



Offline s00da

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Re: Ischia Acetic/Lactic control with temperature
« Reply #16 on: September 24, 2009, 05:14:58 PM »
Bill,

I assume your procedure is 19 hours @70 F and then 5 hours @75 F both in the thermokool unit. I also know the thermokool unit is not that precise considering that you experiment with the Ischia which I believe is very sensitive to temperature. As you can see when I went from 70 to 73.8, things changed a lot.

Previously I used to ferment in the kitchen that I thought to be a consistent 75 F but as you can see from the graph here (yellow line) http://www.pizzamaking.com/forum/index.php/topic,9285.0.html it's really not the case. The temperature was oscillating in the 73.5-78 F range. When I switched to fermenting at the guest room (red line), I was getting mixed results. The dough is sometimes sour and too elastic and sometimes extensible with less sour. Now that I found my perfect fermentation room, the workshop (blue line), I was able to better control things and understand how the Ischia behaves.

I will be getting a thermokool unit, actually it's this one http://www.kotulas.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10051&storeId=10001&productId=14570&langId=-1&?cm_mmc=Housefile-_-SHIPPED-_-1206-_-CONF since I know the workshop will get busy sometimes and with the temperature logger I have, I think I should be able to replicate what I'm doing now and see if this unit is really capable of stabilizing temperature.

I will post a graph for the logged temperature for this unit. I think it will help many of us here on the forum.

Saad

Infoodel

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Re: Ischia Acetic/Lactic control with temperature
« Reply #17 on: September 24, 2009, 05:22:54 PM »
Saad,

Acidity isn't the only thing affecting extensibility (directly). Enzyme activity and specifically protease plays a big part. Enzyme activity will increase with both temperature and hydration (hence poolish vs. biga)  Additionally, at the right levels, acidity produces conditions favourable to proteolytic bacteria activity.
Toby

« Last Edit: September 24, 2009, 05:26:07 PM by Infoodel »

Offline Bill/SFNM

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Re: Ischia Acetic/Lactic control with temperature
« Reply #18 on: September 24, 2009, 05:26:37 PM »
I assume your procedure is 19 hours @70 F and then 5 hours @75 F both in the thermokool unit.
More or less +/- a few hours. I have abandoned a high level of precision. I have not observed the same changes you describe with a change of a few degrees of temperature when fermenting.

I think those of us who are perfectionists, who strive to do the very best we can if we are going to do something at all, go through similar stages when at first we grasp for an understanding of those factors we can control and use precision until we gain a more intuitive and instinctual level of skill and are able to adapt to changing conditions even though we may never know what caused those changes. I'm making dough today for pizzas tomorrow and as I watched the dough coming together in the mixer, I decided to knead it just a little less than usual. I also added a little less starter than usual.

Offline s00da

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Re: Ischia Acetic/Lactic control with temperature
« Reply #19 on: September 24, 2009, 05:31:23 PM »
Saad,

Acidity isn't the only thing affecting extensibility (directly). Enzyme activity and specifically protease plays a big part. Enzyme activity will increase with both temperature and hydration (hence poolish vs. biga)  Additionally, at the right levels, acidity produces conditions favourable to proteolytic bacteria activity.
Toby



Toby, you are correct except that my results are based on the same dough. So I'm talking about using the same ingredients all the way to the brand of bottled water where the only difference was fermenting the dough for 20 hours at 70F against 15 hours at 73.8 F. The difference is big in dough handling properties and sourness as they seem to come together in one package. I think that when I fermented my dough in 70 F, I was basically making one big Biga.

Saad


 

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