Q. Shulchan Aruch 505, 4, says that on Yom-Tov one may measure spices when he is cooking in order not to over-spice the food. Would this also apply on Shabbos if someone is making something like salad dressing which is permitted to make on Shabbos, may he also measure the spices in order not to over spice the food?
A. Piskei Teshuvos (606: 2) mentions that in our days it is uncommon and unnecessary to measure salt and spices with professional or analytical measuring instruments when home cooking and it is a longstanding custom to evaluate by simple visual assessment, therefore, these instruments should not be used even on Yom Tov. However he adds, that common spoons and cups, that are not primarily made for measuring, are permitted. So are baby bottles and cups that have measurement lines, but are not used primarily for measuring.
Horav Shlomo Miller’s Shlit’a opinion is that so are baby bottles and cups that have measurement lines, but are not used primarily for measuring. The Rov added that the same would apply on Shabbos.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a