# Is leaven yeast?



## greenbaggins (May 14, 2008)

I am asking to see if anyone has some clarity on whether this is a legitimate reading of the relationship of leaven and yeast: 

Leaven is not yeast per se. Bread made today from packets of yeast is unleavened bread. Leaven means the lump of sourdough is broken off, mixed with flour, water, etc., and then the new loaf rises. Meanwhile, the remaining sourdough starter is fed with more flour and water, and left to rise, to be used the next day. This can continue for many years; but Israel was told to cut it off and start over every year (from James Jordan's commentary on Daniel, entitled _The Handwriting on the Wall_, pg. 72, footnote 24).​


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## BobVigneault (May 14, 2008)

Wow! You mean leaven is 'Friendship Bread'?


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## VictorBravo (May 14, 2008)

greenbaggins said:


> I am asking to see if anyone has some clarity on whether this is a legitimate reading of the relationship of leaven and yeast:
> 
> Leaven is not yeast per se. Bread made today from packets of yeast is unleavened bread. Leaven means the lump of sourdough is broken off, mixed with flour, water, etc., and then the new loaf rises. Meanwhile, the remaining sourdough starter is fed with more flour and water, and left to rise, to be used the next day. This can continue for many years; but Israel was told to cut it off and start over every year (from James Jordan's commentary on Daniel, entitled _The Handwriting on the Wall_, pg. 72, footnote 24).​



Well, it's true that modern yeast is different from sourdough. The leaven in sourdough is composed of certain lactobacilli (bacteria that eat lactate) and wild yeasts. 

I think it would be a stretch to argue against the commandment solely on the basis that modern yeast is not leaven, considering that the action of modern yeast is pretty much the same as the old sourdough combination of yeast and bacteria. They both digested portions of the dough to produce gas.


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## greenbaggins (May 14, 2008)

victorbravo said:


> greenbaggins said:
> 
> 
> > I am asking to see if anyone has some clarity on whether this is a legitimate reading of the relationship of leaven and yeast:
> ...



What commandment are you referring to? Jordan is arguing that Israelites were to start a new batch of starter each year.


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## VictorBravo (May 14, 2008)

greenbaggins said:


> What commandment are you referring to? Jordan is arguing that Israelites were to start a new batch of starter each year.



Sorry, I jumped to conclusions. I was thinking about the passover commandment, and the relation to the Lord's Supper. As for his argument that they start a new batch each year, I was assuming that he was speaking in the context of the Passover being the time of the new batch.

I wonder what other reference he is making to leaven, though, cause I can't think of any.


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## Contra_Mundum (May 14, 2008)

For what it's worth,
Regardless of which it is, yeast proper or leavened dough (which I think is the more likely referent, because it would "keep"), to be rid of it on an annual basis was a call to repentance. I don't know what JJ's take is (possibly similar) but to purge the leaven was a reminder of leaving this world (Egypt), _in particular its influences,_ behind.

The new year meant a new loaf, none of the old "taste". A godly batch, with godly influence, in the land God promised. But one year later, you realize Egypt's back, sin is in my life, the world is too much with me. Passover time again. Time for new resolutions, time for new repentance, and a fresh start.


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## Leslie (May 14, 2008)

When I was a member of a Messianic Jewish congregation, the rabbi considered yeast, baking powder, and baking soda to all be leaven. During the feast of unleavened bread, we were not to bring anything leavened for the after-service snack table. Leaven is anything that makes dough light and fluffy as opposed to thin and compact.


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## jwithnell (May 14, 2008)

From a baking perspective, yeast is yeast whether you capture wild yeasts from the air or buy yeast at the grocery store. In French bread making, you can hold onto a levain -- I have not idea how to spell it --- which is essentially a lump of dough from the a previous bread-making session. But it is still a yeast-based leaven like any other. I must say, every time I have my hands in dough, which is often, I appreciate the Biblical use of leaven, breads and so forth as illustration.


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## Glenn Ferrell (May 14, 2008)

I’m a sourdough bread baker. A true sourdough culture has wild yeast and lactobacilli in a symbiotic relationship. All leavened breads were sourdough prior to yeast’s discovery by Leeuwehoek in 1680 and Pasteur’s identification of their role in fermentation in 1857. The yeast studied by these two men was beer yeast, _Saccharomyces cerevisiae_, not the wild yeasts of sourdough cultures, usually _Candida milleri_ or _Saccharomyces exiguus_. Modern bread yeasts are varieties of brewing yeasts selected for their fast rising properties, but do not impart the taste of sourdoughs. Some sourdough cultures have been collected and passed down for centuries in given localities. I am currently regularly baking with a Russian sourdough culture brought from a small village north of Moscow (Not Idaho; it’s not a FV culture!), where it was probably preserved and passed on for centuries.

The use of modern bread yeasts was impossible in the Bible, unless they used the residue left from beer fermentation to start their bread. Orthodox Jews would make no distinction between sourdough and bread yeast today.

I’ve wondered myself at the requirement to remove leaven from the house before the feast of unleavened bread. A new culture can be captured from the air without great difficulty; but individual sourdough cultures may have an unique and prized taste; and bakers are reluctant to lose them. So, I’ve wondered if in Jewish communities a bread culture might have been moved to an outside location, kept in a crock for the week of unleavened bread, and then brought back for use the next week. I’d like to ask someone knowledgeable of Jewish culture what the historic practice was.


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## Contra_Mundum (May 14, 2008)

Glenn, I appreciated that run down.

Of course, I could be wrong, (as I have often been), but it seems to me that the purpose behind the purging of leaven would be undermined if the leaven were simply "saved", just outside of homes. Leave it out there for 8 days? Then bring it back in... Did they bring back Egypt's leaven? Seems to me to run against the purpose.

I realize they might get attached to a certain "taste" of the bread, but it seems that was another one of those separation distinctives--no forever sourdough (homemade in the nation, maybe they could buy an old batch from the Sidonians). Pork loin is reeeeally tasty too, but off limits.


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## jwithnell (May 14, 2008)

Many sourdough purists insist on keeping the sourdough for years on end, so it would be interesting to know for sure how this was handled in the Jewish culture. I'm active on a baking forum so I'll see if any of those folks know. I have heard that making unleavened bread, at least in the modern era, requires very specific timing to make sure there is no opportunity for a wild yeast to take hold.

As an aside, I've read that the cook on old western chuck wagons used to sleep with their sourdough to keep it from freezing overnight. That's dedication!


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## VictorBravo (May 14, 2008)

jwithnell said:


> Many sourdough purists insist on keeping the sourdough for years on end, so it would be interesting to know for sure how this was handled in the Jewish culture. I'm active on a baking forum so I'll see if any of those folks know. I have heard that making unleavened bread, at least in the modern era, requires very specific timing to make sure there is no opportunity for a wild yeast to take hold.
> 
> As an aside, I've read that the cook on old western chuck wagons used to sleep with their sourdough to keep it from freezing overnight. That's dedication!



That's funny. My Mom's sourdough froze one night sitting in the kitchen. (We had an old fashioned house with no central heating--on a minus 40 night sometimes the inside of the kitchen would be in the teens).

She was worried about it being killed off, but it worked fine. After that, she always froze a bit for safekeeping and never worried about keeping it going.


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## jwithnell (May 14, 2008)

Re: the chuck wagons; I'm assuming they were trying to keep the sourdough ready to go for the next day's baking. I know plenty of folks who freeze their sourdough over the summer, or whenever they don't want to mess with it for awhile. I don't mind starting over with mine -- likely the same strains are introduced because the flavor doesn't vary much.


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## Grymir (May 14, 2008)

I'm a baker too. Sourdough is wild yeast. Store yeast is like farm raised yeast. And yes, Baking soda, Baking Powder, and yeast (wild or farm) are all leaven. They raise bread. The quote in the OP is not right in the definition of yeast and leaven. You don't have to worry about starting fresh yeast either. It's real easy. Set out flour for a few days according to a recipe, and you 'catch' (breed) wild yeast and start your year again. No biggy. People like to hold on to it usually because of sentimental reasons, but it's not necessary. They were masters of starting sourdoughs way back when too.


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