But rabbis in even some of the most Orthodox associations say chometz
does not refer to all leavening.
"There is nothing wrong about a raised product at Passover per se,"
said Rabbi Moshe Elefant, executive rabbinic coordinator and chief
operating officer of the Orthodox Union's kosher division, the oldest
and most widely accepted certifier of kosher foods.
Lise Stern, author of "How to Keep Kosher" (Morrow, 2004), said:
"Chometz, which means sharp or sour, denotes bread that has a sourness
to it caused by fermentation, occurring when liquid is added to any of
the five grains mentioned in the Torah. This refers to yeast, not
baking powder or baking soda."
Rabbi Soloveichik said: "They're just minerals. What do we care about