Question: [Thursday, 25th Mar Cheshvan, 5781]
Hi. Is it permitted on Shabbos to make seltzer using Soda-Stream with the non-electric model?
While this matter is under debate amongst the Poskim with some claiming that it transgresses the rabbinical Nolad prohibition, as well as other possible prohibitions [i.e. Tikkun Keli] especially if one needs to assemble the cylinder to it on Shabbos. Practically, the vast majority of Poskim rule that is permitted to be used on Shabbos to make soda water and many even permit attaching the cylinder to it on Shabbos [being that it is made for constant entrance and removal and is thus similar to the cover of a bottle]. Nonetheless, I would suggest that the best thing is to make it before Shabbos and certainly not to attach the cylinder on Shabbos. Although if the cylinder is already attached and one forgot to make the soda water before Shabbos than he may be lenient to make it on Shabbos, and those who even attach a new cylinder to it on Shabbos have upon whom to rely, although those who are stringent not to attach a new cylinder and not to even make soda water on Shabbos, are blessed.
Sources: See Ketzos Hashulchan 130 footnote 12 and 146 footnote 32; Minchas Yitzchak 4:122 although it is best to do so from before Shabbos [9:33]; SSH”K 11:35 in name of Rav SZ”A; Yabia Omer 3:21 who also permits the attaching of the cylinder; See Maharsham 3:140; 6:33; Bris Olam Ofeh 91; Chelkas Yaakov 3:168; Tzitz Eliezer 7:24; 20:13; See list of all Poskim who are stringent and lenient in Piskeiy Teshuvos 320:15 footnote 163 and 313 footnote 99 regarding attaching the cylinder.