The topic of mixtures dominates this chapter of Zevachim. Up until now, the mixtures under discussion have generally been made of discrete items — entire animals designated for specific sacrifices or entire limbs of sacrificial animals. The mishnah anchoring today’s daf (which actually begins on the bottom of yesterday’s daf) shifts to discussing liquid mixtures, specifically those involving sacrificial blood meant to be sprinkled on the altar.
While it may not seem intuitive at first glance, this discussion actually ends up being one of the most practically relevant parts of Zevachim. The rules and concepts discussed in today’s daf become a major source for laws of kashrut about mixtures of forbidden and permitted foods. But before we get there, we need to look at the mishnah:
Blood that was mixed with water: If it has the appearance of blood, it is fit. If it was mixed with wine: One views it as though it is water. (Blood) mixed with the blood of a (non-sacred) domesticated animal or the blood of a (non-sacred) wild animal: One considers it as though it is water. Rabbi Yehuda says: Blood does not nullify blood.
As we have learned throughout Zevachim, applying blood to the altar is a crucial step in any animal sacrifice. The mishnah asks if we can still consider something blood for this purpose if it is accidentally mixed with other liquids. We learn that in a case of dilution by water, we go by a straightforward visual standard: If the diluted blood still looks like blood, it is still fit to be sprinkled on the altar. However, in a case of visually similar or identical liquids (red wine or other blood), we cannot use a straightforward visual standard — the mixture will look the same no matter how diluted it is. Instead, we are asked to judge by imagining the mixture’s appearance as though the diluting substance were water. That is to say, if enough of the contaminating fluid mixed with the blood that it would have altered its appearance had it been water, the mixture is considered invalid for sprinkling.
Lastly, we cite a dissenting opinion from Rabbi Yehuda on the final case of sacrificial blood mixed with non-sacrificial blood: Unlike the initial voice of the mishnah, he holds that blood is never able to nullify (or revoke the status of) other blood. Given that they are physically identical substances, one cannot cancel out the other. Rabbi Yehuda thus offers a lenient opinion, permitting the sacrificial blood to be used on the altar even if it has mixed with non-sacrificial blood.
In exploring this concept of mixtures, the Gemara brings a novel statement by Reish Lakish:
Piggul, notar, and impure meat that were blended together: one who eats the mixture is exempt (from lashes); one of the items must have overwhelmed the other and nullified it.
As a reminder, the basic idea of bitul (nullification) is that a problematic substance can be canceled out and made irrelevant when mixed with enough of a permitted substance. Like the mishnah, Reish Lakish here is making a ruling that is also ostensibly about bitul in a homogeneous mixture. Just like the two kinds of animal blood in the mishnah are physically indistinguishable, so too the three problematic types of sacrificial meat in this case could be physically indistinguishable — they have different ritual status, but they all look and taste like meat.
The Gemara notes that this is a shocking claim: While Reish Lakish is not permitting anyone to eat a mixture made up entirely of forbidden food, he does seem to claim that one would be exempt from lashes if they did because each problematic component is cancelled out by the others. Most importantly for our discussion, Reish Lakish seems to have a majority-based standard for nullification, at least on the level to be liable for lashes: One is not liable for eating a mixture which is fully one-third piggul because the majority of it is still not piggul. This is also controversial because we know from other rabbinic sources that the normative standard for nullification is taste: If the forbidden substance in a mixture imparts flavor to the permitted substance, even if it is a small minority, the mixture is nonetheless forbidden. Reish Lakish seems to disregard this and holds that as long as the forbidden food is less than 50 percent of the mixture, it can still be nullified on a Torah level — even by other forbidden food!
Rava challenges Reish Lakish by bringing a case from another mishnah where the nullification standard for a dough mixture is clearly taste, not majority, even on a Torah level. The Gemara resolves this by making a distinction between the cases based on the fact that one is a homogeneous mixture and the other is a heterogeneous mixture. In Reish Lakish’s case, the mixture is homogeneous, made up of physically indistinguishable foods that taste identical. In this kind of case, the standard for nullification is indeed majority (at least for not receiving lashes). However, Rava’s case was a heterogeneous mixture involving two distinct types of flour in a dough. In this case, where one is able to discern separate tastes in the mixture, the standard for nullification defaults to the more stringent metric of taste.
Over the course of many centuries of debate, these rules of nullification ended up being codified in kashrut laws that still dictate much of how observant Jews navigate food choices today. In a tractate of laws that are largely no longer practiced in the absence of a Temple, this chapter offers a window into the very practical applications of sacrificial laws to daily Jewish life.
Read all of Zevachim 78 on Sefaria.
This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on December 1, 2025. If you are interested in receiving the newsletter, sign up here.
