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Whole grain – Does wet whole grain become Chametz?
Not only can dough [which is flour, ground kernels, with water] become Chametz, but even whole grains that come into contact with water can become Chametz. Nonetheless, the criteria required for grain to leaven are different than that of dough and flour. If a grain has begun to sprout, it is considered complete Chametz. If a grain has contacted water and split as a result of the water, then this is a sign that it will certainly immediately become Chametz, and it is Biblically forbidden to eat under the penalty of Kareis. If however the grain has not split, then even if it remained 18/24 minutes with the water, it is only questionable as to whether it has become Chametz, and is thus Biblically prohibited to be eaten due to doubt. If however the grain has softened to the point that it is fit to have split, then it is disputed as to whether it is certainly Biblical Chametz, or only questionably Biblical Chametz. If, however, the grain did not remain 18/24 minutes with the water, it does not leaven and is not considered Chametz. Various laws are recorded in the Poskim regarding what to do if one discovered a grain in his food on Pesach. It is due to this ability for grains to become Chametz that the custom is to guard the Matzahs from the time of the harvest; in order to supervise that the grains do not come into contact with water and become Chametz. This Matzah is known as Matzah Shemura, as it has been guarded from water from the time of harvest.
 Admur 467:1-13 and 25-65; See also 447:22; 453:8-13; Whole Grain soaked in fruit juice: 462:9; 466:2 [soaked in blood for less than 24 hours]
 Admur 453:9
 Admur 467:1 and 32; However see Admur 436:19 regarding kernels on bottom of a pit that “even if some of the kernels have split, it is very likely that this splitting is not due to its becoming Chametz but due to spoiling and loss of the kernel, as it is common for the kernels by the floor and walls of the pit to split due to spoiling and loss, and they are not Chametz at all.”
 Admur 467:2, 7 and 25
 Admur 467:25 and 7
 Admur 467:5
 Shulchan Aruch Chapter 467
 Admur 453:19