Rice, corn, and any other seeds, legumes or grains which are not one of the five grains (wheat, rye, spelt, barley and oats ) are not
ḥameṣ and do not become ḥameṣ even when they are fermented.
The Ashkenazi custom, however, is to forbid the consumption of rice and other grains (qitniyot) during Pesaḥ. Why? The Ashkenazi tradition does not consider rice as ḥameṣ. The reason for the abstention from rice on Pesaḥ is that it was common to find grains of wheat mixed with rice. Either because the fields where rice was grown were usually nearby or within the same fields where wheat was grown, or because whole-rice grains and wheat-grains look alike, and if they were sold by the same seller in the market it was possible that grains of wheat could be mixed accidentally with rice or other grains. As we will later explain, the prohibition of ḥameṣ during Pesaḥ is so severe that even one grain of wheat could render a whole food as forbidden for Pesaḥ.
Sephardic Jews are divided on the issue of rice. Moroccan Jews and other Jews from North Africa also avoid eating rice during Pesaḥ. While Persian and Syrian Jews consume rice during Pesaḥ. However, to avoid the possibility of the accidental presence of a grain of wheat in the rice, the Persian and Syrian custom is to check the rice very carefully three times before using it for Pesaḥ.
One should also abstain from buying enriched rice, which sometimes could be enhanced with yeast or wheat starch. Brown rice could also be used, provided it does not have other additives
For a different reason, and unrelated to ḥameṣ, some Sephardic families refrain also from eating chick peas (ḥumus) and certain types of beans. In this matter, every family should follow its own tradition.