Mashkim Megulim - Uncovered Liquids

One is advised never to consume liquids that were left uncovered overnight, a halachic concept referred to as "mashkim megulim", lit. "uncovered liquids". The liquids which are subject to the restrictions of mashkim megulim are honey, milk, water and water-based beverages (e.g. tea, coffee, beer) and uncooked wine.[1] The rabbis instituted a ban on consuming liquids which were left uncovered for fear that a snake or other similar creature[2] might have drunk from them and deposited some of its poisonous venom in the process.[3] Some authorities even forbid consuming liquids that were left uncovered during the day, even if for only a few moments.[4] Some say that one should be especially careful to observe the rules of mashkim megulim in the Land of Israel.[5]

It is not necessary for liquids to be tightly sealed in order to evade the restrictions of mashkim megulim, even a loose covering such as a plate or napkin will do.[6] One may keep liquids uncovered in the refrigerator as they are deemed to be sufficiently safeguarded from snakes in this way. It is also noted that such venomous creatures avoid cold places anyway.[7] Similarly, the restrictions of mashkim megulim do not apply to liquids that are boiling. As such, soups that are cooking on the stove top should be kept covered until they begin to boil, at which time they may be uncovered.[8]

The restrictions of mashkim megulim only apply to uncovered liquids that were also left unsupervised. If, however, there was someone in proximity to the liquids, even if only a baby, the restrictions of mashkim megulim do not apply as long as the person remained awake.[9] There are those who maintain that liquids which were left unsupervised for less than twenty minutes are not subject to the restrictions of mashkim megulim, either.[10] One should not take the issue of mashkim megulim lightly as it is an enactment intended to protect our health and well-being. In fact, violating enactments which are intended to protect our health is often worse than violating prohibitions of the Torah.[11] Our sages teach us that one who knowingly puts oneself in any form of danger is deserving of lashes.[12]

Nevertheless, many authorities rule that the ban on consuming mashkim megulim no longer applies. This is because snakes and scorpions are uncommon in residential areas, especially inside people's homes.[13] Others disagree, arguing that even if this is true, there may have been mystical considerations for the enactment of mashkim megulim that we are unaware of and therefore the enactment should continue to be observed.[14] Indeed, as a general rule, all rabbinical enactments remain binding even if the original reason for the enactment no longer applies.[15] This is especially true regarding matters that were instituted for our health and safety.[16] Although normative halacha is in accordance with the view that mashkim megulim no longer applies, it is certainly praiseworthy to observe it.[17] 

Even one who is not careful to observe mashkim megulim should not use wine which had been left uncovered for Kiddush or Havdalla.[18] If, however, such wine was left uncovered for only a very short period of time, then it may be used.[19] One who must use wine that was left uncovered for Kiddush or Havdalla must be sure that the taste and aroma of the wine was not affected.[20] Nevertheless, one who has other wine readily available should use it rather than use wine which was left uncovered for even a brief amount of time.[21] There are additional grounds to be lenient with regards to using wine which was left uncovered for the daytime Kiddush.[22] Wine which was left uncovered in a closet or refrigerator may be used for Kiddush or Havdalla without reservation. One should never use wine that was left out all night long, no matter what the circumstances.[23]

One is not permitted to try and determine whether or not a liquid has been poisoned by simply examining it. This is because many forms of animal poison are indiscernible to the naked eye.[24] One who is careful to observe the restrictions of mashkim megulim should not give such liquids to someone else to drink, even that person does not observe them. Some authorities maintain that one should not use mashkim megulim for washing one's hands and not even for washing the floor.[25] It is permitted, however, to feed mashkim megulim to cats as they are said to be immune to snake venom and other poisons.[26] Most authorities rule that it is permitted to leave water uncovered beside one's bed at night in order to wash one's hands upon awakening in the morning as required,[27] though some authorities forbid leaving water uncovered even for this.[28]

[1] Terumot 8:4; Rambam, Hilchot Rotzeiach 11:7.

[2] Nefesh Adam, Hilchot Gilui 14.

[3] Avoda Zara 30a; Terumot 8:4; Rambam, Hilchot Rotzeiach 11:6.

[4] Rambam, Hilchot Rotzeiach 11:11; Aruch Hashulchan, YD 116:3; Rivevot Ephraim 5:11.

[5] Birkei Yosef, YD 116:3; See also Minchat Yitzchak 9:85.

[6] Orchot Rabbeinu.

[7] Shevet Halevi 6:63.

[8] Rambam, Hilchot Rotzeiach 11:8; see also Rivevot Ephraim 4:217.

[9] Midrash Rabba, Noach 34:12; Perisha, YD 116:12.

[10] Divrei Malkiel 4:1.

[11] Devarim 4:9, 4:15; Chullin 10a.

[12] Rambam, Hilchot Rotzeiach 11:5.

[13] Tosfot, Beitza 6b; Tur, YD 116:1; YD 116:1; Mishna Berura 160:23.

[14] Levush, YD 116:1.

[15] Yabia Omer, YD 10:24.

[16] Levush, CM 427:11; Maaseh Rav Ha'aruch 97.

[17] Pitchei Teshuva, YD 116:1; Kitzur Shulchan Aruch 33:5.

[18] OC 272:1; Aruch Hashulchan, OC 272:5; Beit Yehuda 43.

[19] Magen Avraham 272:1.

[20] Mishna Berura 272:3.

[21] Kaf Hachaim, OC 272:9.

[22] Divrei Malkiel 4:1.

[23] Az Nidberu 1:7.

[24] Tur, YD 116.

[25] Avoda Zara 30b; Tur, YD 116.

[26] Rashi, Shabbat 128b.

[27] Shaarei Teshuva, OC 4:7.

[28] Rambam, Hilchot Rotzeiach 11:15; Shulchan Aruch Harav, Shemirat Haguf V'hanefesh 7; Ma'aneh Eliyahu 18.