Maran clearly delineates the three conditions necessary to perform Borer (selecting) on Shabbat. First, "Ochel Mitoch Pesolet," one is allowed only to take the good from the bad. Second, "B’Yad," one is allowed only to use his hand and not a designated vessel for selecting. Finally, "MiYad", only selection for immediate consumption is permitted.
However, on Yom Tob, the parameters governing borer are more lenient. One difference is that on Yom Tob selecting the bad from the good is permitted in certain cases. The Halacha states that the criterion for selecting on Yom Tob is based on "Tirha," the method which is least cumbersome. If the majority of the mixture is the non-desirable element, then, of course, one must take the good from the bad. However, if the majority is desired, one should take the bad from the good, since this involves the least effort.
Another major difference is with regard to "MiYad," the requirement to select for immediate consumption. The Mishna Berura (Rav Yisrael Meir Kagan of Radin, 1839-1933, siman 510) rules that on Yom Tob, the rule of MiYad does not apply. One can select even if it is not intended for immediate use. For example, one is permitted to select an ingredient from a mixture in the morning that will not be needed until later in the afternoon. Of course, it is prohibited to select for use the next day, unless Yom Tob was Friday, in which case it is permissible to select for Shabbat with an eiruv tavshilin. Hacham Ovadia (Hazon Ovadia p. 76) concurs with this ruling.
The basis for this ruling is the general leniency of Yom Tob with regard to Melechet Ochel Nefesh, activities necessary for eating. One is allowed to cook and bake on Yom Tob. The Mishna Berura reasons, just as with regard to cooking there is no stipulation that the food be cooked immediately prior to the meal, so too, with regard to Borer. On Yom Tob, it has the status of Ochel Nefesh vis-a-vis the requirement of MiYad, although the condition of B’Yad still applies.
SUMMARY
On Yom Tob, it is permissible to select and remove the non-desired element from a mixture comprised of a majority of desired elements.
On Yom Tob, it is permissible to select from a mixture even if the item selected is not needed until later in the day.
