Browse Zemanim: Pesah: What is Hames?
The five types of grain from which hames can be made are wheat, spelt, barley,
oats and rye.
When any of these are mixed with water and left standing, fermentation
begins. The mixture coagulates, swells, pales and its surface cracks. Whether or
not this is then baked into bread, it is hames. The fermentation process takes some
time, is aided by warmth and being left standing and is only stopped by the intense
heat of baking.
We take flour which had never come in contact with water,
mix it with cold water and constantly knead the dough, roll it out and thoroughly
bake it before fermentation can get underway. The Sages set the maximum time allowed
at eighteen minutes. The resulting bread is unleavened and free of any suspicion
of hames. This is massa.
Hames which was once fit for human consumption remains
forbidden as long as it is edible to man or animal. However, if it has become inedible
even to an animal before Pesah (like ink and cosmetics which may be made from hames)
it is no longer called hames and one may use it on Pesah and even swallow it (e.g.,
in medicines) as long as it is not made up into a pleasant tasting mixture (as in
coated tablets, throat lozenges, etc.).