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Is yeast chametz
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Seraph




 
 
    
 

Post Sun, Mar 22 2009, 1:17 am
chavamom wrote:
Seraph wrote:
shalhevet wrote:
I asked dh about this. He says yeast just doesn't work with matza meal/ potato flour etc because it's a chemical reaction with the flour. He said if it worked you can be sure it would have been marketed by now.

If I had time I'd try this out before Pesach, but I guess the experimenting will have to wait till Iyyar.
I dont know. Knowing science, I really think I'd disagree with your husband. Yeast eats carbohydrates. Yeast would still eat cooked carbohydrates that are in matza meal.


You are right but only have part of the picture. It eats carbs and produces gas bubbles. BUT the bubbles have to be trapped by strands of gluten (which is why you have to knead bread to make long strands of gluten) to make things rise. Once it is baked, you see those trapped bubbles as the air pockets in the dough. Matzah meal isn't going to break down and form strands of gluten to trap the bubbles. Make sense?
Then tell me, how does baking powder or baking soda and lemon juice work on pesach?
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louche




 
 
    
 

Post Sun, Mar 22 2009, 2:37 am
Yeast produces CO2 gas through a biological process. baking soda uses a chemical process. when you mix baking soda--sodium bicarbonate--with an acid like acetic acid (vinegar) or citric acid (lemon juice), the acid-base reaction gives off CO2. double-acting baking powder contains sodium bicarbonate plus several different calcium and aluminum salts. The initial reaction is the bicarbonate-acid one, which is why the recipe must include some acid. But in double-acting powder, a second CO2-producing reaction takes place when the batter is heated. Using baking soda alone gives an immediate, quick rising, but the product must be cooked at once before the bubbles give out. Baking powder gives you more time.

Yeast requires a source of sugar or starch to grow. The baking soda reaction does not. Just for fun, mix some baking soda and vinegar in a bowl (or the toilet bowl) and see the fun! For even more drama, put a small dish inside a large bowl. Put a small candle in the dish and a handful of baking soda in the big bowl. Light the candle. Then, carefully pour some vinegar down the side of the big bowl so that it mixes with the baking soda but doesn't splash on the candle. Watch what happens.
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chavamom




 
 
    
 

Post Sun, Mar 22 2009, 12:54 pm
I'm not an expert in the science of baking, but I do know that what I wrote about yeast and gluten is true. That is why people who have gluten allergies/celiac disease have such issues with getting bread that will rise. They generally have to add a gum-substance to the non-gluten containing flours to get it to rise. Otherwise, the dough can't trap the CO2 that the yeast produces. I think that baking soda and baking powder provide a minimal amount of leaven, but not enough for a cake. That is what all those ubiquitous egg whites are used for!
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Seraph




 
 
    
 

Post Sun, Mar 22 2009, 2:25 pm
Ok, so my question sorta still remains- why is yeast assur for pesach?

And how does matza meal trap the co2 bubbles from baking soda without the gluten strands?
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StrongIma




 
 
    
 

Post Sun, Mar 22 2009, 3:15 pm
my LOR told me that yeast is not itself chametz.
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chavamom




 
 
    
 

Post Sun, Mar 22 2009, 3:42 pm
Seraph wrote:
Ok, so my question sorta still remains- why is yeast assur for pesach?

And how does matza meal trap the co2 bubbles from baking soda without the gluten strands?


I don't think you get much "rising" with matzah meal and baking soda. Most things made with matzah meal need eggs for lighteness.
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louche




 
 
    
 

Post Sun, Mar 22 2009, 5:35 pm
Seraph wrote:


And how does matza meal trap the co2 bubbles from baking soda without the gluten strands?


It doesn't. The egg protein in the cake coagulates around the gas bubbles as it bakes, forming a spongy-textured skeleton. With bread the skeleton is gluten protein; with egg the skeleton is albumin.
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amother
Blonde


 

Post Thu, May 02 2019, 2:54 am
Does the Ou consider Fleishmann's Yeast Chametz Gamur or not?
chavamom wrote:
OK, here is the OU's psak:
Quote:
Yeast

The Torah says that one may not own se’or on Pesach. Are se’or and yeast the same thing? A quick lesson in bread baking will surprisingly show that se’or is yeast but yeast isn’t necessarily se’or!

Although a grain which soaks in water for 18 minutes is chametz, in order to make good bread one needs yeast. Yeast is the living microorganism which converts some of the flour into the carbon dioxide which fluffs-up the batter and causes it to “rise”. The air we breathe contains yeast, and therefore if one makes a batter of flour and water it’ll eventually rise even if no yeast is added, because yeast from the atmosphere will find their way into the batter. But most bakers don’t have the patience to wait all day for their bread to rise, so they add their own yeast into the batter to speed things up a bit.

The traditional method of collecting/creating yeast is as follows. Every day the baker would take one handful of dough out of the batter and not bake it. As the day went on, the yeast in that dough would multiply (and be joined by other yeast found in the air) to such an extent that that the batter would turn sour and inedible. This ball of concentrated yeast would be thrown into the next day’s batter to help that batter rise (and a handful of that batter would be taken out to be saved for the next day… ) . In English this concentrated yeast-ball is called “sourdough” due to its awfully-sour taste, and this is what the Torah calls se’or and forbids one from owning on Pesach.

However, one can also collect yeast from plant sources and produce it via fermentation. If yeast doesn’t contain any ingredients from the 5 grains (as it often doesn’t) it isn’t chametz even though it has the same characteristics as se’or (see Mechiltah 9:19 on Sh’mos 12:19) and one may own it on Pesach. [The process of “fermentation” and the possible chametz concerns it raises will be discussed below]. Thus, se’or is concentrated yeast but the yeast which is commonly sold in stores is not se’or.

Brewer’s yeast is yeast recovered from beer production (discussed below). It is similar to se’or and one may not own it (derive benefit from it or eat it) on Pesach.


Does the OU consider Fleishmann's Yeast used for baking, Chametz Gamur?
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amother
Gray


 

Post Thu, May 02 2019, 5:51 am
chavamom wrote:
OK, here is the OU's psak:
Quote:
Yeast

The Torah says that one may not own se’or on Pesach. Are se’or and yeast the same thing? A quick lesson in bread baking will surprisingly show that se’or is yeast but yeast isn’t necessarily se’or!

Although a grain which soaks in water for 18 minutes is chametz, in order to make good bread one needs yeast. Yeast is the living microorganism which converts some of the flour into the carbon dioxide which fluffs-up the batter and causes it to “rise”. The air we breathe contains yeast, and therefore if one makes a batter of flour and water it’ll eventually rise even if no yeast is added, because yeast from the atmosphere will find their way into the batter. But most bakers don’t have the patience to wait all day for their bread to rise, so they add their own yeast into the batter to speed things up a bit.

The traditional method of collecting/creating yeast is as follows. Every day the baker would take one handful of dough out of the batter and not bake it. As the day went on, the yeast in that dough would multiply (and be joined by other yeast found in the air) to such an extent that that the batter would turn sour and inedible. This ball of concentrated yeast would be thrown into the next day’s batter to help that batter rise (and a handful of that batter would be taken out to be saved for the next day… ) . In English this concentrated yeast-ball is called “sourdough” due to its awfully-sour taste, and this is what the Torah calls se’or and forbids one from owning on Pesach.

However, one can also collect yeast from plant sources and produce it via fermentation. If yeast doesn’t contain any ingredients from the 5 grains (as it often doesn’t) it isn’t chametz even though it has the same characteristics as se’or (see Mechiltah 9:19 on Sh’mos 12:19) and one may own it on Pesach. [The process of “fermentation” and the possible chametz concerns it raises will be discussed below]. Thus, se’or is concentrated yeast but the yeast which is commonly sold in stores is not se’or.

Brewer’s yeast is yeast recovered from beer production (discussed below). It is similar to se’or and one may not own it (derive benefit from it or eat it) on Pesach.


Rabbi blumenkrantz says something similar. Baking yeast is ok and brewers yeast may be a problem. I read it this year after throwing out my opened yeast ☹️
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