I recently learned that a davar gush in a keli sheini has the din of a keli rishon. Therefore one would need to wait till the food is no longer yad soledes to add raw spices like pepper to it. Is this correct according to all opinions? Is there room for leniency in a case of someone who does not want to wait for the food to cool off and would like to add pepper to his food right away? Would using a spoon to place the food on the plate from the pot transform it to a keli shlishi? If so, but if the food is still yad soledes would it make any difference?
Although a davar gush has the power to be maflit and mavliya even in a keli sheini, authorities dispute whether it also has the power to actually cook something for purposes of Shabbos.
The Magen Avraham (318:45) is stringent in this matter, as are a number of poskim (Maharshal, Yam Shel Shlomo Chulin, Gid Ha-Nasheh 44; Shach Yoreh De’ah 94:30 and 1-5:8; see Peri Chadash 94 and Taz 94:14), and one must therefore be careful not to add raw spices to a davar gush.
This is the ruling given by the Mishnah Berurah (318:65).
See, however, Halichos Olam Vol. 4 p. 50-51, and Or Le-Zion Vol. 2, p. 239, who are lenient, and Sephardim are generally more lenient in this matter.