Instant Soup and Mashed Potatoes on Shabbos with Cold Water

Question:

1. Is it against Sabbatical law to use room temperatures water to cook an instant soup on the Sabbath?
2. What about instant mashed potatoes?

Answer:

1. 1. There are two potential Sabbatical law issues with pouring water into instant soup. The prohibition not to cook, called “bishul” (cooking) and the prohibition not to make separated items into a combined entity (called losh or kneading). Both of these issue do not apply to adding cold water to instant soup. The soup is not getting cooked, as the water is not hot, and the noodles and other ingredients are not getting bound together to form a new entity, since the noodles are going to remain separate from each other and will not be stuck together. Therefore it is permitted to make the instant soup using room temperature water.
   2. Regarding the mashed potatoes however, while the first issue will not apply, as the water is cold, the second issue will apply, since the potato flakes will bind together as a result of adding the water to them. Therefore the mashed potatoes should not be made on the Sabbath. It can however be made before the Sabbath.

   Best wishes

Sources:

Orach Chaim 318-6,14,  Igros Moshe O:CH 4-74 Losh 7.