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The status of eating yeast on Passover has me confused. Yeast is used in wine production which is ok to eat, but I've talked to people that won't eat yeast extract, which is not a leavener. Is there a correct answer or is this a gray area?

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Possible Duplicate: – jake Apr 11 '12 at 22:11
I read the "duplicate" before posting but it doesn't answer my question – Jarrett Widman Apr 11 '12 at 23:34
Hello Jarrett, welcome to Judaism.SE, and thank you asking this very timely question! I hope to see you around the site! – HodofHod Apr 17 '12 at 0:48

2 Answers

up vote 4 down vote accepted

My understanding is it all depends on what the yeast grew. If it grew off of wheat or barley or the like, it's a problem.

As I heard from one OU lecture, an interesting ingredient in today's food production is "torula yeast." Paper makers had all this "pine wood soup" from cooking their shredded pulp, which they couldn't just pour down the drain for environmental reasons. So a type of yeast which loves to eat pine soup became popular, breaking down the waste product much better -- and as it turns out, torula yeast is a nice food ingredient, and all it's grown off is pine wood, so there are virtually no kashrut or allergy issues with it! (May still need Passover supervision, though.)

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According to this glossary, Se'or, the somewhat lesser known, but no less prohibited, sibling of Hametz, includes the yeast extract products known as Marmite and Vegemite. Unfortunately, I don't know on what basis they make this assertion. I can think of at least two possible reasons, but I am not sure of either of them.

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I think they may be flat-out mistaken. Se'or is sourdough (used as a starter for leavening bread), not yeast. (Although maybe indeed the yeast in the products they mention are grown on a chametz substrate at some point, or that chametz is used at some other point in their manufacture.) – Alex Apr 11 '12 at 23:27
@Alex - do you think that yeast extract would then be ok if it was grown on a food that was also ok to eat? – Jarrett Widman Apr 11 '12 at 23:35
@JarrettWidman: at least theoretically, yes. Practically speaking, of course, CYLOR. – Alex Apr 11 '12 at 23:39
@Alex, that is why I qualified it by stating I don't know the source for their assertion. – Seth J Apr 12 '12 at 13:58
@JarrettWidman pinging you too. – Seth J Apr 12 '12 at 13:58

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