- Question: Why does one make a blessing of “al biur chometz” at the time of burning when he found chometz on Yom Tov but before Pesach we say the blessing by the checking, bedikas chometz?
A. The Magen HaAlef (2) poskins that if one realizes on Yom Tov that he did not check for chometz before Pesach then he should check for chometz and cover it if he finds any because it is muktzah on Yom Tov and then on chol hamoed he should burn it with a blessing.
B.Normally we say the blessing and check for chometz the night before the eve of Pesach, then burn it in the morning, which is the proper time to burn the chometz, before chatzos, noonish. By chatzos all chometz is forbidden and automatically made ownerless by the Torah if you have not done it yourself by then.
C. In normal circumstances the checking at night is considered the beginning of the mitzvah of burning and that is why the blessing is said then.
D. In both cases the checking and burning are on different days so why is the blessing said at different times?
Answer: As long as the time for burning hadn’t come yet then the checking is considered the beginning of the process of burning but once the time of burning already past and you found chometz on Yom Tov but you can’t just burn it until chol hamoed then the checking isn’t considered the beginning of the mitzvah since the time you burn has already past, so finding it is just one action and burning it is another action which just couldn’t be done earlier since it was muktzah. (See footnote 4 in Dirshu Mishna Berura 435:1:3)