Zevachim 78: Mixtures; The Status of Rice

In keeping with their discussions about mixtures of items that are consecrated, today the rabbis consider combining types of foods.

• Masechet Pesachim 35 teaches that although rice can 'rise', or become chametz, leavened, it cannot be baked into matza
• Masechet Challa (3:7) rules that dough made from a mixture of wheat and rice  can be made into kosher (for the mitzvot of Pesach) matza as long as it tastes like wheat
• Rabbeinu Tam states that this reminds us about foods forbidden because we can taste something forbidden
• The Ra'avad notes that a person would have to eat a kazayit, an olive bulk - of wheat to fulfil the mitzvah of eating matza on Pesach
• Masechet Challa (1:1) of the Yerushalmi Talmud teaches that wheat flour causes rice flour to ferment thus become chametz
• Steinsaltz teaches us in notes that rice was brought to Israel from the Far East by the Mishnaic period
• Rice was traditionally used in combination with other grains and as cereals rather than bread on its own (because it is missing the bonding agents that bind bread together)
• Sages held differing opinions on the status of rice and thus which blessing was proper, whether it could become chametz, whether it could become matza, etc.