Rav Avi: Hi, welcome to Responsa Radio, where you ask and we answer questions of Jewish law in modern times! I'm Rabbi Avi Killip here with Rabbi Ethan Tucker, Rosh Yeshiva of Mechon Hadar, a center for higher Jewish learning based in New York City. Alright. How are you today?
Rav Eitan: I'm good, Avi, how are you doing?
Rav Avi: I'm really excited about this question that we're gonna do today, because I think this question is particularly fun for anyone who has ever found themselves trying to explain kashrut to someone, and in particular trying to explain the ritual of kashering dishes and how that works. And I think this particular question that we have on the table today is one that comes up a lot, and that I think a lot of people have trouble articulating or, you know, when you go to explain it, you realize maybe that you didn't 100 percent understand it yourself. So I'm excited to lay it all out on the table, as they say. "I have heard that utensils no longer affect the food prepared in them once they have sat unused for a day." By utensils here we mean dishes and pots also. "Why do we need to kasher things at all, then? Couldn't we just let them sit for 24 hours?"
Rav Eitan: Okay. Yes.
Rav Avi: Such a good question!
Rav Eitan: It's a great question, this is in, like, every rabbi's toolbox of getting all the different kashrut questions, how to think about this stuff. So, alright. I hope we can get to some clarity here, not just on the practice, but also on the theory. Alright. So, let's start at the beginning of why, why is there even a notion of kashering at all. And I think in one of the really early Responsa Radio episodes, we kind of in passing mentioned something about this, so I'm really glad we're getting back to kind of do this properly on its own terms.
Okay. So, why do we have this at all? This all begins in a text in the Tosefta, which talks about people who are purchasing vessels, klei tashmish, things that are going to be used for food, from gentiles, from non-Jews. The text ultimately is understood as essentially to be dealing with buying them from a non-kosher source, so it applies, you know, also to things bought from Jews where it was not kosher. But it lays out the following rule: it says if the item was never used at all, then you immerse them, and they're pure, they're ready to be used. If they were used, but, like, cups or flasks, then you rinse them in cold water. If it's something like a cauldron, a kind of water-heater of sorts, any container that uses hot liquids, those you're supposed to rinse or immerse and boil in water, and if it's, like, a knife or a spit or different things that are used on an open flame, so the knife here you're imagining, you know, something used for grilling, something like that — those you make white-hot in an open flame, in fire, and then they're all ready to be used. Okay? So —
Rav Avi: So these are all different ways to make vessels kosher, so to speak.
Rav Eitan: Yeah, that's right. And it's very clear from the original context here that there is a ritual, even if the thing was never used. Right? Even if the thing was never used before, when it goes from the non-Jewish environment to the Jewish environment, you sort of do something, you immerse it. And, you know, as we've talked about in that earlier episode, the history of immersing things is a whole other story which starts here and flowers out from here. But it's very clear that the sort of way you bring this vessel into permitted Jewish kosher use is on some level by undoing its prior identity. In other words, if it was used for, like, drinking and water like that, so you rinse it in cold water, and that sort of reverses it. If it's used with hot water, you use it in hot water. And if it's used on an open flame, you use an open flame. This is a purging ritual; it is the thing that essentially is meant to take an object that had an identity being used in one way, and to undo it by using that same means to reverse its identity. Alright?
Lest we be unclear about this, the text then goes on and says, and you know, by the way, if you used any of the items for food, before you rinsed it in boiling water, immersed it in water, torched it in the fire, then the food is still permitted. Meaning, making very clearly here in the Tosefta, that this is a sort of procedural requirement of what we're doing when we take a vessel from a non-kosher to a kosher status.
But if you just read the Tosefta, it doesn't actually do anything to the vessel itself. The purging is not about getting stuff out of the vessel; the purging is a sort of, like, reversing the identity of the thing itself, and therefore if you forgot or you didn't do it yet, well, there's nothing wrong with the food you cooked in them, it's just, okay, now next time before you use it again, make sure you go through that process.
Rav Avi: This may be obvious, but let's just clarify that there's nothing wrong with the food if there was nothing wrong with the food. Meaning, you know, if what you made was a veggie lasagna that would otherwise be kosher, then the vessel is not gonna cause the problem.
Rav Eitan: That's correct. 100 percent, we're assuming if the ingredients are fine, then it seems according to the Tosefta, nothing about the pot's prior history is going to undo that. Alright? And therefore the bottom line is, even if you didn't do any of those rituals, mutar, it's permitted to benefit from the food, and I think we can fairly presume, but you're still supposed to do that purging ritual next time before you use it again. Alright. That's in the Tosefta.
Rav Avi: So this is then an after-the-fact situation — once I already have the food in my hand, it's not giving me permission to borrow a pot from my neighbor who doesn't observe kashrut and use it to cook, right?
Rav Eitan: Not on the surface level, though maybe we'll get to that in a future episode, because what's considered suboptimal can sometimes be somewhat expansive. So maybe we'll come back to that. But, yeah. The simple case here is, don't do this, but if you messed up, you don't have to throw the food out. Okay. That's all fine and well, until we get to the Talmud Bavli. And here, when this text comes into the Talmud, a really important thing happens. First of all, a second version of the text emerges, where one version says the food's okay at the end, if you did it, you know, if you cooked it by mistake without having purged the vessels.
But then another version of the text says it's not okay. So, you get a kind of second opinion that says that even after the fact, you have a problem. That's one thing. But much more significant is that the Talmud then throws in and says the whole basis for this law is, we're worried about the trapped flavor in the vessel. What we're actually concerned here about is the non-kosher food that was used in this vessel in an earlier iteration somehow is now gonna leach back out and affect the food that's being consumed here. And that really completely alters the whole orientation of the discussion, because now we're not just talking about kind of reversing the identity, undoing its status; we now seem to be talking about something physical, like a physical thing that has to be accomplished, which is getting rid of this food or this flavor. And we'll come back to that in a second, in terms of all its ramifications.
But a second thing happens in the Talmud, which is there as a kind of obscure and not entirely clear statement by an amora, by a rabbinic sage there, different names in different versions, who says the Torah only forbade a kederah bat yoma, a bowl or a dish or a utensil which is bat yoma, something like "of that day," or "of that time." Okay? I deliberately am translating it in an obscure fashion because it's not clear from the local context what it means. But whatever it does mean, it is clear that this rabbinic figure is saying that the only thing the Torah forbids, and that seems to mean the only thing that's really forbidden, is something that has this status of being bat yoma, and anything that's not in that category is technically permitted.
Now, very quickly the dominant interpretation of that phrase comes to mean, was used in the last day. The Torah only cares about vessels that were used in the last day. Things that were used much further back in time than that, the Torah is not concerned about its possibility of forbidding the food that's cooked in it. So let's just say it out, what does that look like, like, as a practical conclusion? And then we can dig a little deeper. It would mean, let's say I have a pot that was used to cook a pork-rice dish. Okay? According to this statement, if that pot, you know, no longer has, like, an actual, you know, visible piece of pork adhering to it, and has been sitting around for three days, and then someone uses that pot to cook with, the food will be permitted. It'll be a mistake, they shouldn't have done it, but you'll be allowed to eat that food. Whereas if it was used to cook that pork-rice dish that same morning, and you now are, you know, cooking it with that pot for dinner, then not only is that forbidden to do that, but the food in that pot will also be forbidden, because it's a kederah bat yoma, it's a pot that was used in that same day.
Rav Avi: Right. The one-day marker seems so short, you know — the idea of don't use something that was used today feels really logical. The idea that if it was used yesterday, I could use it, feels very soon, but I don't know, maybe that's a symptom of, I will confess, I own many pots that go many days unused, and maybe biblically that was much more rare.
Rav Eitan: So, yeah. This goes also to the definitional questions, because what do we even mean by "in the last day"? That itself is not clear. So, Rabbenu Tam, the great medieval sage, said "the last day" means anything where a full night has passed. Meaning, he thought that you could get up in the morning and, you know, if you used something for breakfast that was a treyf pot that shouldn't have been used, but it had been used the night before, right, even though it's only like 12 hours earlier, that was sufficient. His nephew, Rav Yitzchak of Danpierre said no no no, this is a 24-hour standard, and that's what leads to our current practice, which is to say, right, overwhelmingly the dominant practice is to say if the pot has sat unused for 24 hours, it loses its ability to forbid the food that's cooked in it, and that's why one of the first things, whenever a rabbi gets a question of, oh G-d, I did such-and-such with this pot or that pot, they'll always ask, well, what was used in the past 24 hours? Because the second you eliminate that concern, then the temperature drops considerably, and you probably don't end up having to throw out food.
Rav Avi: So, I think you've made this clear, but I feel like I need to say it again, just because it always feels so surprising to me, is that we're not just talking about, I cooked a dairy kugel in a meat pan; we are even talking about, I cooked a pork and rice dish last night, and tomorrow morning I can use that dish to make omelets.
Rav Eitan: Okay, good. So what you just said is exactly the elision, the slippage that our questioner is asking about: cases that if you accidentally use that pork-rice pot to cook breakfast in, you are able to eat, you know, the omelet or whatever it is that you prepared in it. But you are not allowed, affirmatively, to go ahead and do it. And that is because of a later line in the Talmud that comes along and says, well, wait a minute — if pots don't affect anything 24 hours out, why don't we just use them? Why do we have a purging ritual at all? Right? Why don't we just say, after 24 hours have passed, you can go ahead and use it. To which the Talmud's answer, though it's not really the Talmud — it's pretty clear it's a later edition to the Talmud, because it's sort of messed up in different manuscripts and appears in different ways — someone comes along and says, well, that must be that we've gotta be strict about pots that have sat around for more than 24 hours because of the core case of pots that have not sat around for more than 24 hours. Meaning it's a kind of fence around the law — if you start letting people use pots that have just, you know, just let them sit around for 24 hours, soon enough they're gonna start using pots without purging them within 24 hours, and you're going to end up actually violating the Torah's concern here.
Now, truth be told, someone who digs a little deeper here will notice a few things that don't fully make sense. If the whole discussion here is about flavor, right, which I said already, the Talmud seems to say this is about flavor leaching out of these pots, so the first thing you can ask is, well, I don't know — why does that flavor really disappear after 24 hours?
Rav Avi: Right, right. Is there an assumption that you washed the pot in 24 hours, or not necessarily?
Rav Eitan: No, there's not, and the Talmud itself has to sort of say, well, we have a kind of presumption that the flavor goes bad, contributes a negative flavor, after 24 hours. But it seems a little subjective, and certainly across the board, it's a kind of blanket rule for something that seems like it would have a lot more variability. The other thing is, well, okay, let's even say you need some kind of purging ritual to get out the flavor, and the 24-hour timeline is about right for when that flavor, you know, is affecting subsequent food — but aren't there other ways to get the flavor out, other than going through these purging rituals? Particularly once you've got soap, and all kinds of detergents and all sorts of things, if the concern here is only the flavor leaching out, shouldn't we just be able to run stuff through a dishwasher?
Rav Avi: Yeah, great question.
Rav Eitan: You know, not obvious at all. And this is part of what we talked about in this earlier session. And this is where you get a sense of the gap, sometimes, between the kind of original sense of the law that always stays with us, as opposed to the way it might get talked about at later points in time. So this is pretty clear: someone who reads the Tosefta — the original law is not really about getting food particles out. It's pretty clearly about just changing over the identity of the object by doing the thing you normally do with it. Alright?
And so then, I can run through all the dishwashers in the world — if it was used as a spit in fire, one of the ways I kind of psychologically undo it is by passing it once through fire in a way that kind of, sort of undoes that identity, leaves that identity by the wayside, and then now I use it again for a new sort of Jewish kosher purpose. And yet, a later discourse for all kinds of reasons, which someone who's a real martyr can read my dissertation about, the Talmud passage here introduces a kind of discourse of flavor, but no posek is ever willing to get rid of just the purging identity reversal of this, because it's never really imagined that that discourse totally takes over all the contours of the law.
And here too, I actually think I would suggest there's something going on with the 24-hour rule that is less in some intrinsic space about the flavor wearing out, and more something about a significant psychological barrier between how recently was this pot used for non-kosher food? And here's where, actually, Rabbenu Tam's standard of a night passing is highly significant. You get up in the morning and you use stuff in your kitchen — it's like, I don't know what I used this for yesterday! Right? It's literally yesterday's stuff. And certainly, in the case of a 24-hour application, it's sort of enough time that we think of it as, right, who can remember what they had for breakfast yesterday? Right? Most people can't. And that reflects a certain moving from different days to different places in time, where, yeah, the history of this pot ceases to become relevant, at least for the purposes of, you know, thinking about how it affects the food.
Rav Avi: I also think the going to sleep and waking up in the morning feels to me like ritual — you know, it's a daily ritual as opposed to a kashrut ritual, to go to sleep and wake up in the morning, but in that framing of it, as opposed to, well, was it 12 hours or 24 hours? There's still an element of ritual that is significant, that the kashrut, the system of kashrut involves the need for ritual which is sometimes — and you know, I read a definition of "ritual" recently that was, I can't remember exactly, but something like "a pretend reality," or "a reality that we imagine onto the world." Which, you know, is sort of a different way of thinking about ritual, but sometimes with kashrut I think that definition of ritual can be really helpful, that it's — you imagine that it's a new day, it's a reset.
Rav Eitan: Yeah, I think it's actually great language that's helpful here, because if you try to reduce kashrut only to the mechanics of food particles, you will run up against what seems like a stubbornness of poskim not to go to certain lenient places that won't make sense to you, but once you realize there's a kind of identity of vessel ritual changing-over component, suddenly it makes a lot more sense. So the questioner on some level here is coming from a place of, well, if this is all about flavor, and after 24 hours the flavor expires, why in G-d's name do I need to do this stuff with boiling water?
And truth be told, from the perspective of food particles, they're right. But from the perspective of actually thinking about, well, what does it mean to make a pot kosher, or to say that a pot is dairy and becomes meat, and all those sorts of things, actually has this ritual component. Now, where those two can sort of converge, I think, in a fascinating way, is in the context a lot of the materials revolution — stainless steel, various kinds of Pyrex and, you know, certainly glass, which is not new, but we have certain kinds of tempered glass today — there, I think, actually two things go on. To the extent that you have statements in halakhah, both starting in the rabbinic period and the Middle Ages and then today, that there are certain materials that just don't absorb any food at all, and therefore they don't have to be kashered at all, because they're completely non-porous, on the surface you have a statement that seems to be about food particles, right? Which is saying, well, there's no food particles in this thing because it's non-porous, so therefore I can use it without kashering.
But I actually think there's also something else going on there, which is, non-porous materials also tend to look brand-new. They tend to look not really that different after three years of use than they do at the beginning. That's the whole thing with stainless steel, right? I mean, unless you really burn it and ruin it on the stove, it is stainless steel, right? And in that sense, sure, you can tell it's not brand-new, but in a deep sense, it doesn't carry with it the psychology of earlier uses in the way that other materials like wood and unglazed ceramics and all kinds of things — they do. You really see it. I just have to throw out one more thing, which I think is fascinating here, just to give people a sense of how the 24-hour rule is the way we've come to internalize this, but it's not the only way that it was thought of.
Rav Meir Halevi of Abolafia, known also as the Ramah, who was a medieval Spanish sage — so he read the bat yoma description here, which we've been referring to as "in the last day," totally differently. And based on a different Talmudic passage, he said, no no no, a kederah bat yoma is a dish that was only ever used for one kind of food. So "bat yoma" doesn't mean "used on that day;" but it means "has sort of a singular quality to it." And what he then says, it's fascinating, is the sage here in the Talmud means that the Torah only forbids using pots that were used for one food, where one kind of flavor will emerge from it. But once a pot has been used for two, three, four, five different kinds of things, it then has a whole mix of different, you know, flavors and histories, that essentially cancel one another out. And again, that is something that I think is getting at a kind of — it's a sort of food particle discourse, but it's also getting at some of the psychological ritual piece, where it's saying if this is the pork pot, then of course if you use it afterwards, even three weeks later, we're gonna treat it as if it forbids your food.
But if this is just a pot that was used to cook all kinds of stuff, I can't really trace it back, you know, to one particular forbidden thing that is now directly contaminating my food. And while this position does not really live on in any live way in halakhic discourse, you occasionally see it — I encountered it first through Rav Ovadia Yosef's writing, who sort of, he'll pull it out as an added factor to be lenient in a case that he feels already he has grounds to be lenient, and to say, look, this is a pot that was used for all kinds of food, and we already know that according to the Ramah, that pot wouldn't be a problem b'dievad, after the fact, no matter what the circumstance.
Rav Avi: Yeah. That feels very intuitive to me. I don't know, especially, I think, as a person who grew up in the South, where there's a lot of treyf and there's a lot of, sort of, like, dishes specifically for it that would be like, you know, this is my shrimp cocktail bowl, that, you know, it's sort of like, sure, maybe I can have a cold glass of milk in someone's bow, but I wouldn't want to have a cold glass of cereal in their shrimp cocktail bow. That would feel different to me than, you know, a bowl that they use for lots of things, and may have had a shrimp cocktail in it in the past.
Rav Eitan: Yeah. And it's really interesting that way because it really is a different standard, right? It's sort of more lenient in the sense that it would allow you to be more lenient even within 24 hours, as long as it was a pot that had been used for lots of things, but if it's a pot that's only been used for one thing, then you would say, well, I don't care about the 24 hour rule — that thing is used for that treyf, you know?
Rav Avi: It's like, is it an either-or concept, or are more definitions that you'd want to take on, each as a chumra, as a way of being a little bit more strict with yourself?
Rav Eitan: Yeah. So I hope we've given this person the answer. And the sort of meta-answer here is — sometimes when there's a halakhic requirement that seems like, hey, that's not following the kind of strict parameters around what I thought this discourse was about, maybe actually you have to enlarge the problem and the question and say, maybe my assumption of what this whole thing is about is limited, and maybe there's actually more than one factor going on here. In this case, using your helpful terminology, some ritual component that is a part of kashering that really transcends the question of just the food science.
Rav Avi: Yeah, I think this is very helpful, and I hope that our questioner both doesn't find themselves needing to throw away too much food unnecessarily, and at the same time that they are able to really find the meaning and the value in the process of kashering and not just waiting 24 hours.
Rav Avi: Have a halakhic question you'd like answered on the show? Email us at halakhah@hadar.org. Or you could leave us a voicemail message at (215) 297-4254.