Today’s interview focuses on a problem that many people face when kashering for Pesach. New-age technology = new-age problems. How do you kasher glass stovetops? Can they be kashered at all? What about induction stovetops? Let’s hear what Rabbi Dovid Cohen, Administrative Rabbinical Coordinator at the cRc, has to say on this timely topic.
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Transcription
R’ Yitzchok Hisiger: Hello everyone and welcome back to Let’s Talk Kashrus presented by the Chicago Rabbinical Council. Today I am privileged to be joined by Rabbi DovidCohen, administrative rabbinical coordinator at the cRC, the Chicago Rabbinical Council. Rabbi Cohen, how are you?
R’ Dovid Cohen: Amazing.
R’ Yitzchok Hisiger: It’s great to have you back.
It’s been a little while since we did an episode together. Today we’d like to discuss a very fascinating but very practical topic that’s important to many people, especially as we approach Pesach and that is glass stovetops. So tell us the halachicstatus of glass stovetops as it relates to kashering them. Can that be kashered and if yes how?
R’ Dovid Cohen: Right so that’s a really good question because we’re Ashkenazim and Ashkenazim don’t kasher glass.
We know we don’t kasher glass. So your first look at it you say no this is impossible I can’t possibly kasher this material. So in order to answer that question we have to back up a drop. Okay why don’t we kasher glass? Sephardim consider glass doesn’t absorb at all.
So it’s a chumra. The Rama says it’s a chumra that like some shitas that it’s a little bit like cheres. A little bit we treat it like a kli cheres something made of ceramic or porcelain that we can’t kasher that the Torah says you can’t kasher so glass is a little bit like that because it’s made in a similar way. Okay the way they manufacture it is similar.
So since it’s a chumra the Rama says some place else whenever we’re kashering things as with libbun as a chumrawe can do a lighter kind of libbun. We call it libbun kal. You get away with not as strong of a libbun as you would really require if it was cheres. If it was cheres you have to put it into its burning super hot you know a thousand degrees.
But for this you can get away with a little since it’s only a chumra to treat it like that you get away with a lesser temperature. Okay now that lesser temperature is he describes it as kash nisraf the amount of heat that would cause a piece of straw to burn on the other side. It’s so hot but it’s not as hot as libbun. libbun I said thousand it’s probably 850 degrees but you don’t have to have that hot but you still have to have like about 450 500 degrees really hot that it could burn a piece of straw on the other side. So when we as Ashkenazim are used to saying we don’t kasher glass that means we don’t kasherglass with hag’ala with hot water.
If we do libbun kal if we heat it up with enough temperature to make it kash nisraf to make it that hot that we can kasherlike that. So that’s our goal. We want to kasher it by making it as hot as kash nisraf. We’re not we can’t do hag’ala you can’t pour boiling water on it like on I don’t know your stone counter but you can do it by making it kash nisraf.
R’ Yitzchok Hisiger: Okay we know there’s a principle of k’bolo kach polto. So how does that apply to glass where we’re you know how does that determine what type of kasheringyou could do for a glass?
R’ Dovid Cohen: Okay so k’bolo kach polto is used for two purposes. It’s to decide which type of kashering it needs does it need libbun or hag’ala like that type and within those what the level of it. Let’s say if I only poured something chometzonto my counter I can kasher it by pouring something onto it.
So within the levels I can choose that. But what when I’m in the when I require libbun like on a glass I need libbun you don’t get to choose what temperature it is. You can’t say as I’ll do a little higher or lower based on how hot the food was when it goes in. That doesn’t work.
In hag’ala it does. In hag’ala if it was only 160 degrees I could kasher with 160 degrees but in libbun kind of things and even libbun kal it doesn’t work like that. So whatever the temperature was that’s the temperature. Okay so what we’re our goal here is to get libbun kal we want to get it heated up.
So you say I know how to get it heated up it’s easy it’s got electric coils underneath it so you turn it on it’s gonna get nice and hot. Okay so that brings us to another complication and that’s because there’s another din which is when we kashersomething and we make it hot let’s say with in this case with heat with fire the fire has to be or the water has to be on the side where the food was not on the side where the fire was. So in this case where was the chometz or the treif that’s on my glass counter? That was on the top part of it. Well where’s the coil that I have? The coil that I have is underneath.
The coil is underneath so usually let’s say when you think about kashering your counter by pouring boiling water onto it the chometz would have been on the counter and the water is going to be on the top of the counter so you’re doing it the right way. Here the fire is underneath and the food was on the top. Okay so that’s not the way to kasher. You can’t kasher by putting heat on the wrong side.
So some people argue back and they say no but for libbun it’s different. Maybe with libbun it’s different and you don’t you could have the fire on the wrong side. Okay now there’s such a thing there’s a machlokes achronim about that but that machlokes is about libbun gamur when you make something burning hot like that’s even hotter and that’s because they say is because there it’s as if the thing is on fire itself the whole thing is on fire. But it doesn’t work for libbun kal.
So some people say it’s okay it’s only glass anyhow it’s just a chumra so it’s okay even though the fire is a little on the wrong side some people get away with that. And some people say no, lema’aseh you have the fire on the wrong side. Okay, so if you think like that, what should you do? What am I going to do? I have this, this is my stovetop, what am I supposed to do? So for that there’s a solution and that is basically he says I’m not going to kasher my stovetop. Okay, well how am I going to cook? What I’m going to do is I’m going to make sure my pots never touch the stovetop.
And that’s by using these disks. These disks are really made for a different kind of glass stovetop, I’ll talk about that for a second afterwards, for an induction stovetop. And these are for induction stovetops, can only use certain kind of pots on them, ferromagnetic pots. So if you don’t have that kind of pot in your house, you put this disk down and the disk takes the role of that.
But for our purposes, you can buy these on Amazon, any place, Target sells them, everybody you can buy them.
R’ Yitzchok Hisiger: What’s this called?
R’ Dovid Cohen: It’s called an induction disk. It’s just really for our purposes it’s just a metal disk and the point is when you put this down on the stovetop, the pots that you have are not going to touch the stovetop. So I didn’t kasher my stovetop, you’re right I didn’t kasher it.
Okay. But I didn’t ever put the pot on, I never put the pot onto the stovetop. Right. Okay, so this works and you can put these down.
Just a word of caution that if you think about what you’re doing is you’re leaving this on your stovetop, it’s going to be burning hot. Okay. So you should not take this off, of course not with your hands. Okay.
Even some people have burnt their gloves trying to take them off because they get so hot. And someone else told me, someone told me also they took it and they put it onto their counter, their counter was Formica and they melted, no I’m sorry, their Pesach counters were covered with something plastic, they covered it, they put this down, it melted right through that. So anyhow, it comes with a little handle to lift it off so you don’t have to touch the heat yourself and put it down someplace that can handle the heat. Okay.
Now and it brings me to mention, I’ll mention two other things. One is even the glass stovetops if you kasher it by heating up the turning on the burners, it only kashers right around those burners. The space in between doesn’t get kashered. And one last thing was I mentioned quickly about the induction stovetops.
Induction stovetops, I don’t know if you’re familiar with it, it’s a more modern kind of stovetop and in it it’s glass on top, but there’s no coils underneath it. When you turn it on you don’t see, it doesn’t get hot at all. Okay. And it works through, it’s not important how it works, it’s something called induction.
It makes your pot hot but it itself doesn’t ever get hot. So those stovetops have no way to kasher them. You can’t get them hot, it just doesn’t work, there’s no way to get them hot. So for those you have to use these disks.
That’s the only way to do it. You will not have kashered it and you just put your pot on top of that.
R’ Yitzchok Hisiger: Any final thoughts on this topic as regards to Pesach or kashering from kosher to treif? Any other thoughts?
R’ Dovid Cohen: The induction, the only final thought is about the induction I’ll just throw in.
Induction has its own issues with Shabbos and bishul akumissues. In other words, if you think about it, an induction stovetop, when you pick your pot up actually the coil stops producing electricity. So it has Shabbos questions, it has other complications. If a person has an induction stovetop…
R’ Yitzchok Hisiger: Meaning turning it on is not going to help for if a goy…
R’ Dovid Cohen: Right, when you turn it on nothing happens, but if a goy comes and puts food on, that’s a bishul akumproblem. It’s a Shabbos issue also every time you put the pots on and off. So a person with an induction stovetop really needs to ask shailos.
We were just talking about the kashering part of it. They have to just think about it, it has other complications. But for a regular stovetop again, some people will do what we said, turn on the coils and that kashers the area right around them. Right.
And other people are not comfortable with that and they just use these disks instead. Excellent. Thank you so much.