Sous-vide Bath: A Kosher Path?

Continuing the technology series, we are moving on to the sous-vide and the halachik challenges that arise with it. Rabbi Dovid Cohen - Administrative Rabbinical Coordinator at the cRc, fills us in on potential kashrus issues with a sous-vide.

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https://askcrc.org/item/Keilim/968499 R’ Yitzchok Hisiger: Hello everyone and welcome back to Let's Talk Kashrus presented by the Chicago Rabbinical Council. Today I am joined by Rabbi David Cohen, administrative rabbinical coordinator at the Chicago Rabbinical Council. How are you Rabbi Cohen?

R’ Dovid Cohen: I'm doing fine thank you.

R’ Yitzchok Hisiger: Today we'd like to discuss a very very unique item, a unique machine that people use called the sous-vide and its halachic ramifications.

First let's talk about what a sous-vide is. What is it? How would you describe it?

R’ Dovid Cohen: Okay, it's a really unusual way to cook. Instead of taking your piece of chicken or piece of meat and sitting it in the oven at 350 degrees, you put it into this basically into a water bath. Okay, now that sounds really strange, what in the world? So before, you don't just put it right into the water bath, you put it into a bag.

It's called sous-vide because that bag you suck all the air out of it. It really means under vacuum. So you suck all the air out of this bag and you put it into the water. So the bag keeps it from getting waterlogged, okay, and you put the meat into the bag and dunk it into the water.

And then what you're going to do is you're going to heat up that water to just the right temperature to cook the meat. Which is to say is you've probably heard, the government will tell you when you're cooking a piece of meat it's ready when the meat thermometer tells you it reaches 145 degrees, 165 degrees, whatever it is. That's the internal temperature because the cooking does something to the meat, whatever it does to make it edible. And when it's ready, it's gotten up to a certain temperature.

So basically you program your machine to heat the water to exactly that temperature. So that means is instead of at 350 in your oven, it's always cooking at 150 or 160 or whatever temperature you cooked. So it's really slow. Cooks at a really slow temperature, but you can't burn your food because it can never get hotter than what it's supposed to be.

And it takes really hours and hours and hours to cook the food. Instead of an hour it could take three four hours. And again the idea is to be able to cook it more accurately. More accurately, more evenly, without burning it.

And because it's in the bag you don't lose any of the moisture, everything stays inside of it. And it has a certain kind of cooking that people appreciate.

R’ Yitzchok Hisiger: Have you ever tasted meat from a sous-vide?

R’ Dovid Cohen: I have not. Sorry.

Sorry, I'm just the rabbi side of it, not the chef side of it.

R’ Yitzchok Hisiger: I'm curious to hear what the difference between the taste between a sous-vide and a conventional oven is.

R’ Dovid Cohen: You have to ask somebody else. Sorry I'm not the guy to answer that question.

Okay, but so that's what people do. And it's a kind of cooking. It's not the kind of thing like oh gosh we're going to eat in 15 minutes. You have to be well planned in advance and it takes many hours to cook it.

Like there are things that will take a roast could take 24 hours to cook. A piece of meat might take three four hours to cook. So it's a slow process and somehow it makes food that tastes whatever it is and some people appreciate that. Okay, so first now that we understand what that machine is, I'm sorry, I forgot to describe the main part of the machine.

There's something called an immersion circulator. And it looks, basically when I told you put the meat into a big bucket of water, into a pot, into a container, that's any container you want to use. But the real what makes it work is this immersion circulator. And that is it's a rod, you could see it here in the animation, it's a rod that sticks into the water and has in it a heating coil so it heats up the water and has a fan or an impeller on the bottom of it to circulate the water.

So it, you program it on the top, you push in I want it to be at 145 degrees for six hours. Okay, and that's what it'll do. It'll heat up the water, once it gets the water to temperature, it'll clock down from you said six hours and then after six hours it'll turn itself off. So what it does is that circulator circulates the water and keeps all the water at exactly the right temperature.

Exactly the temperature you picked and I forgot what I said 150, that's what it does, 150 degrees for the entire six hours. And the coil goes on and off just to you know keep it at the right temperature and this fan is spinning around keeping the water moving. And basically your meat sits there on the bottom in the bag or in the pouch and it does its cooking. Okay, so the first question people have about it is can I use it for milchigs and fleishigs? Okay, can I make in it something milchigs and then something fleishigs? Now there's not so much that people would make milchigs, but I guess people can.

So the answer would be no they can't do that. And the reason is because although the food is inside a pouch, the food never touches the water. But the din is that ta'am passes through a kli also. So even though it's in a pouch, the ta'am can pass through.

So basically if I used it today for meat, then it became fleishig. And if I want to use it tomorrow for milchig, I wouldn't be allowed to. I could use it for fish which is a very is a popular thing. People use meat and fish.

And that's because meat and fish you just can't cook together. But you could use the same pot as long as it's clean. So if today I put in meat, tomorrow I empty it out and I want to put in fish I could do that. But not milchigs and fleishigs.

Now that leads to another question which people have is okay I want to use it for milchigs or more likely I want to use it for Pesach. Okay what can I do now? Can I kasher this machine? You told me okay you told me don't use it for both, but what happens I want to kasher it? What happens if I bought one or used one from someone who doesn't keep kosher? So now I have a treif one; okay, he used it for treif meat. Can I kasher it to be able to use it now for kosher meat? So, I'm going to give you the short version of it. We have a shiur on it, more complicated.

We'll send people the link if they want to to hear the shiur that there is about this. But the thing is like this: at first you look at it and you say, of course I could kasher it. It's meant to go into boiling hot water. It's meant for hot water.

That's the whole thing is designed for that. Right. So easy enough. Boil up water.

Boil up water and dunk it in. Okay, now you have to be a little, if I could use the word generous, which is to say is you're supposed to go the water up till this high, you have to kasher a little more than that because water splashes around a little bit. Right. But and you can't get the very top of it because the electronics probably wouldn't be able to handle the water of it.

But it's meant to be in water. So you say, easy enough, easy enough. I'll boil up a pot of water, I'll dunk it in and and so on, everything's perfect. I'll kasher it.

That sounds like the easy part. Right. But here's the complication. Everything's got it, you always there's always going to be a catch, right? And the catch is that the Rema says things that have little cracks and crevices you can't kasher.

Well, if you look at, if you pick up your sous vide, this immersion circulator, you'll see there's a zillion cracks and crevices. There's the holes where the water comes into, there's the fan, there's a heating coil, all that all stuck all together. It's all kinds of cracks and crevices where it's really hard to get it clean. Okay.

So that's the question. Can I kasher this if I can't get it clean? The Rema says if you have things like that, you can't kasher them at all. So that's our that's the potential issue. Okay, well what's, so okay, what's the other side? The other side is that wait a second, no food ever touches this machine.

Remember the food's... It's only ta'am, right? Yeah, the food's in a bag. The food's in a pouch. Okay, so I mean it happens that a pouch breaks but basically the food's in a pouch.

So if the food's in a pouch, how's food ever going to get stuck in those little holes? Water is going to go in there but water's going to go in and out. Nothing's going to happen with the water. So on that's one side to say, come on guys, nothing's going to get stuck in the little holes because there's only water passing through the holes. That's all that's in there.

Okay. But then there's another side. The other side is well, people who cook food don't cook it in a lab setup. What I mean is just because the food's in the pouch doesn't mean they don't get greasy hands touching the outside of the pouch and getting food on the outside.

It doesn't mean that there aren't things, grease and all kinds of stuff going on in there. And there's another side which is imagine if food actually did get caught in there. You wouldn't even begin to be able to clean it out. It's hopeless.

It's totally hopeless. It's not even like something with little holes that you could try. You can't even try over here. So people take different approaches.

At the CRC we tell people that they could kasher it from treif to kosher but not for Pesach. Pesach where chametz is b'mashehu they shouldn't, they shouldn't do that. But others would say is, come on, even for Pesach you could do it because realistically no food gets into there. And the truth is also it's pretty hard to think of a case where someone would make chametz in there.

It's mainly for meat and fish. Right. We can come up with cases. You wouldn't believe there are people who actually bake cakes in there.

Oh really? It sounds strange as it is, but yes there's such a thing, people make cakes in there. But also, but imagine if you cut a knife, cut with a chametz-dik knife, you may cut food, cut an onion in there, so it could be chametz in there. But so CRC tells people not to do it for Pesach but for year round, we tell people they could kasher it. Okay.

R’ Yitzchok Hisiger: Any final thought on the sous vide?

R’ Dovid Cohen: On this part of it, no. No. For the, for the kashering and these kind of thing I think I think we covered it. Okay.

R’ Yitzchok Hisiger: Thank you so much.