Why does he considers whey as being pareve whereas it is clearly pareve only mideoraita and not midrabanan (according to Tosfot, the Rosh considers it as being dairy even mideoraita)?

Sources: http://www.dafyomi.co.il/chulin/insites/ch-dt-114.htm https://oukosher.org/blog/consumer-kosher/dairy-primer/ (point IV)

  • From your article, it seems he was clearly convinced that whey was the Mei Chalav the tamud labels as pareve. Regarding the Rosh, he might have a different interpretation of the difference between nisubei dechalva OR he might hold that the micro-filtration used by modern plants renders it mei chalav even according to the Rosh and would make it muttar even miderabanan Commented May 18, 2016 at 14:18
  • Thanks! But the Talmud labels Mei Chalav as pareve MIDEORAITA only.
    – far22
    Commented May 18, 2016 at 14:37
  • @far22 It's clear from both sources that R"M held modern whey was mei chalav, so it clearly avoids the Rosh and the S"A on nesuvei chalba being assur either de'oraisa or derabanan. Specifically the Beit Yosef claimed mei chalav was assur miderabanan. Alas I do not have a copy to check his language, but perhaps R'Moshe disagrees with the B"Y regarding this (that the rebanan didn't rule on mei chalav)? Commented May 18, 2016 at 15:45
  • @IsaacKotlicky thanks! It does not avoid Tosfot saying mei halav is pareve only mideoraita (BY seems to follow Tosfot on this point). Perhaps the answer is that R'Fenstein only follows the Rosh but the Rosh wrote that whey is Nesuvei Chalba! In this case, why does R Fenstein held that modern whey is different from ancient whey (and that it is mei chalav and not nesuvei chalba)? So there is a problem with both Tosfot and the Rosh.
    – far22
    Commented May 19, 2016 at 9:06
  • 2
    nah, that wasn't me. Commented May 23, 2016 at 13:18


You must log in to answer this question.

Browse other questions tagged .