Q. I heard that some people don’t eat matzah balls or dunk matzah in their soup as they are Gebrochts. What does this mean?
The water with which the flour is to be mixed is made ready the night before and then the mixing and baking are done with such speed that no spontaneous fermentation can take place. Once baked, the matzah cannot become chametz (Pes. 41a etc.).
From the inception of the Chassidic movement, some people refrained from soaking matzah in water in order to be absolutely sure that there was no transgression.
The argument is that the matzah may contain flour which is not completely baked and could become chametz if it touched liquid. Soaked matzah is Gebrochts in Yiddish.
They did however permit the baking of Pesach cakes, but with potato flour, not matzah meal.
Ashkenazim did not generally accept this stringency, so they have no problem with matzah balls, matzah gateau and the like.
Those who do follow the Chassidic view do allow themselves matzah balls, etc., on the 8th day of the festival in the Diaspora, when the 7-day prohibition of chametz is a rabbinic but not a Biblical rule.