A person should not engage in activities that require close attention by the light of a fire if there are grounds for suspecting that he may adjust the fire; see 275:1-12. Taking fuel from a fire, even if the fuel is not yet burning, is forbidden (264:3;265:1-2;275:12). Any action that may cause a fire to burn more intensively is forbidden (see 277:1-3), and so is any action that may cause a fire to be extinguished unless there is danger that the fire may spread out of control (see 277:5;334:23) or unless the action has no immediate effect (see 265:4;334:22-24). On what things may be rescued from a house that is on fire, or from other dangers, see 334:1-21; on allowing a non-Jew to extinguish the fire (etc.) see 334:25-26. When there is danger to life or to public safety, a Jew is allowed to extinguish a fire; see 334:26-27.
It is forbidden to separate inferior material from food; but it is permitted to separate food from inferior material, or one type of food from another, if the separation is done by hand and for immediate consumption (319:1-5,8,17;324:1). Separation of food from its natural covering should be done only by hand or in a nonstandard way (319:6-7; 321:1,19). Straining a liquid is permitted only if it is clear (see 319: 9-13,15) or at the time of drinking (319:16), but it is permitted to pour off the top layer of a liquid (319:14). On spraying a liquid see 319:17. Squeezing juice from fruit whose juice is commonly drunk is forbidden (320:1-6) unless it is squeezed directly into food (320:4-5), but juice that comes out by itself is permitted if it began to come out before the Sabbath (see 320:1-3). Squeezing liquid out of food in order to eat the food is permitted (320:7-8). Ingredients may be added to food even if they cause it to change color (320:19-20). A person should not deliberately crush ice or salt to extract water from it, but he may allow it to melt or dissolve in water (320:9,11-14), and he may break through ice to reach the water under it (320:10). Small quantities of salt water may be made, provided it is not strong (321:2). Large quantities of food should not be salted unless it is to be eaten within a short time; see 321:3-6. A person may grind spices or salt in a nonstandard way (321:7-8), or crumble bread (321:12), or chop food up finely with a knife (321:9), but not with a grater (321:10), and fruits or vegetables may be chopped only for immediate consumption (321:12); see also 321:19 on crushing and smoothing food. A honeycomb may be removed from a beehive if it was detached or crushed before the Sabbath (321:13). It is forbidden to mix large quantities of roasted grain with water, and if it has been ground, it should be mixed with water only in a nonstandard way (321:14;324:3); and it is forbidden to mix finely divided substances with liquid so that they become a single mass (see 321:15-17;340:11-12). It is permitted to wash utensils that may be needed on the Sabbath (see 323:6-8), but they must not be washed with a substance that dissolves or that smooths their surface (see 323:9-10).
Cooking is forbidden; on food that began to cook before the Sabbath see Ch.21, and on what may be done with food that was cooked on the Sabbath see 318:1-2. Cooking in the sun is permitted, but cooking in something that was heated by the sun or by a fire is forbidden (318:3). Heating solid food that has already been fully cooked is permitted, provided it is done in an indirect way, but food that contains a significant amount of liquid must not be heated if it has become cold, and additional cooking of partly cooked food, or cooking food that was previously baked or roasted, is forbidden (318:4-5,15-16). Adding uncooked spices or condiments to food that is still cooking is also forbidden (see 318:9,19), and soaking food to make it edible is forbidden (318:4). On warming food on top of a pot see Ch.21. Some foods cook more easily than others, and should not be put even into hot water even if it is in a pot that is no longer or has not been on the fire; see 318:9-10. On heating cold water in hot water or vice versa see 318:11-13 and 326:3. Foods or liquids may be warmed near a fire, but only in a place where they can never become hot; see 318:14,17. Food that has not been completely cooked should not be stirred even after it has been removed from the fire (318:18).
Shulchan Aruch, Copyright (c) 2000 Project Genesis, Inc.