The term the Rambam — and his source, Mikveot 7:3 — use literally means appearance. The intent is, however, color. See parallel rulings in Hilchot Berachot 6:7, Hilchot Bi’at HaMikdash 5:12.
As explained in Halachah 9, the intent is not that the water is permanently disqualified. Rather, while its color has changed, it is unacceptable for immersion. If it reverts to an ordinary color afterwards, it may be used for immersion.
As evident from Halachah 7, the color of the water must be changed due to the natural color of the liquids and not due to other factors.
This applies even if less than three lugim of the other substance change the color of the water.
I.e., they can be counted in the 40 se’ah required for an acceptable mikveh and their addition never disqualifies a mikveh, as explained in the following halachah.
Three lugim of them disqualify a mikveh and never are they counted in the 40 se’ah required for an acceptable mikveh, as stated in Halachah 4.
They are never counted in the 40 se’ah required for an acceptable mikveh, nor do they ever disqualify a mikveh, as stated in Halachah 5.
Moreover, if a pool containing drawn water freezes and becomes ice and then thaws, it is acceptable to be used for a mikveh (Shulchan Aruch, Yoreh De’ah 201:31).
Mud with the consistency of saliva [the Rambam’s Commentary to the Mishnah (Mikveot 7:1)].
Even if snow or the like were collected with an implement, they do not disqualify a mikveh as long as they did not melt while in the implement (Shulchan Aruch, Yoreh De’ah 201:30). In practice, in recent years, mikveot have been made in places where rain does not descend by collecting snow from neighboring mountains with wire mesh shovels in a freezer truck and then shoveling it into the mikveh’s reservoir.
The Rambam mentions crushing the snow because snow takes up much more space than water does. From the Rambam’s words, it appears that he permits immersing in the snow before it melts. There are, however, authorities who rule stringently and forbid immersing in the snow until it melts (Rama, Yoreh De’ah 201:30; see also Siftei Cohen 201:71 who elaborates).
For these are basically considered as drawn water (Turei Zahav 201:34).
A dinar is a coin frequently used in the Talmudic era with a mass equivalent to approximately 5 grams; i.e., a very small amount. As in Chapter 5, although the Rambam’s source, Mikveot 7:3, mentions a kortov, a small liquid measure, the Rambam mentions a measure of weight.
In Halachah 1.
And thus was considered as acceptable.
Now these 40 se’ah are not made up entirely of the original water, but instead contain some of the other liquid that fell in. Nevertheless, since the mikveh was already classified as acceptable, it is not removed from that category.
As stated in Yevamot 82b and the Shulchan Aruch, Yoreh De’ah 201:24, this leniency applies only up to half the measure of the mikveh. The rationale is that as long as the major portion of the mixture is acceptable water, the additional liquid is considered as batel, nullified. See Chapter 4, Halachah 7, and the gloss of the Kessef Mishneh there.
It is not considered as if wine or oil fell into the water, but rather filth. Hence the water is not disqualified (Beit Yosef, Yoreh De’ah 201, in the name of the Ra’avad).
For it is considered as if drawn water fell into the mikveh (Shulchan Aruch, Yoreh De’ah 201:25).
Because it is only the color of natural liquids that disqualify a mikveh.
Our translation is based on the Rambam’s Commentary to the Mishnah (Mikveot 7:3).
Even if the wine does not change the color of the water to that of wine, as long as it is no longer the natural color of water, it is unacceptable (Siftei Cohen 201:66).
The Turei Zahav 201:38 understands this phrase as implying that, in this situation, even if the mikveh contains more than 20 se’ah of acceptable water, one may not pour drawn water outside the mikveh and let it flow inside. Although generally this is acceptable (see Chapter 4, Halachah 8), in this instance, it is invalid, because it is possible that the amount of drawn water that is necessary to cause the color to revert is greater than the amount of acceptable water the mikveh originally contained.
I.e., the water is not disqualified in an ultimate sense, it is merely temporarily invalid.
And thus one may add as much water as one desires (see Chapter 4, Halachot 6-7, and notes).
Even the portion whose color did not change is unacceptable for immersion (Ra’avad).
If, however, the mikveh is larger and one immerses in 40 se’ah of water whose color did not change, the immersion is acceptable (Ra’avad, Siftei Cohen 201:67).
Possessing less than 40 se’ah of acceptable water.
Because the water is now considered as diluted wine.
We do not say that the other liquid is subsumed within the water and they become a single entity.
Implied is that it is liquids and not foods that can disqualify a mikveh, because they cause its color to change (Mishnah Achronah).
