Question: Can I squeeze a lemon for salad dressing on Shabbos?
Answer: The Shulchan Aruch (OC 320:1) writes that it is forbidden mideoraisa (prohibition of sechita) to squeeze olives and grapes on Shabbos as these fruits are planted primarily to make oil and wine. It is forbidden derabanan to squeeze other fruits such as pomegranates or strawberries to make drinks on Shabbos. The Shulchan Aruch (320:6) writes that one may however, squeeze lemons on Shabbos. Elsewhere (Beis Yosef OC 320), he explains that people in Egypt would do so on Shabbos. Firstly, he reasons, as lemon juice can’t be drunk unless it has been diluted, it isn’t considered a regular juice. Secondly, they would do so into sugared water, rather than into an empty container (See Teshuvos Harosh 22:2).
Many of the poskim challenge this, as lemons are primarily grown for their juice. The Mishna Berura (320:22), Kaf Hachaim (OC 320:36) and R’ Yehoshua Neuwirth (Shemiras Shabbos Kehilchasa 5:5) write that as nowadays, juice is primarily squeezed to make lemon juice for drinking, one mustn’t squeeze the lemons straight into water or into an empty container. Rather, one should squeeze the lemons onto sugar before adding water.Nonetheless, squeezing lemons directly onto a salad wouldn’t pose a problem (See Shulchan Aruch OC 320:4).