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Does double vacuum bagging food for sous vide cooking measurably increase the cook times? Or is the extra bag not thick enough to make an impact?

Aaronut
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Eli Lansey
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    If there's any air space between the two bags, then you might be defeating the purpose of sous vide. – Chris Cudmore Oct 24 '12 at 18:37
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    @ChrisCudmore You're probably right. But vacuum sealed each time should minimize that. Many recipes suggest double-bagging for durability on foods that require a very long cook time. – Eli Lansey Oct 24 '12 at 19:58
  • I agree with Sean, this will have no effect if there's no additional air in between, but why are you doing this anyway? – yossarian Oct 25 '12 at 19:14
  • @yossarian Two reasons to do it. 1) Many recipes suggest it for durability with long cook times. 2) For the purposes of kosher food, the same bath can be used for milk and meat foods. – Eli Lansey Oct 25 '12 at 19:22
  • i've never seen a recipe call for 2 bags even for recipes 72h in length. No matter how many layers of plastic between your food and the water some transfer of ions will occur so I guess there is an acceptable level of tolerance for kosher foods? – Brendan Jan 29 '13 at 16:21
  • @Brendan The general rule is that "double wrapping" food is OK. We're not concerned with transfer of ions; a whole discussion of kashrut-science related issues will take far more than the characters allowed in a comment ;) – Eli Lansey Jan 29 '13 at 17:32
  • it's an interesting conversation topic i think that's for sure. I wonder if there would be a market for someone to develop a "kosher" sous-vide packaging for those purposes. Seems like a money maker! – Brendan Jan 29 '13 at 20:25
  • @EliLansey what type of vacuum machine are you using to double bag? Chamber or edge sealer? – Brendan Feb 18 '13 at 14:34
  • @Brendan At the moment, Ziplock bags with the water displacement method. I realize that increases the amount of insulating air sneaking in. – Eli Lansey Feb 20 '13 at 21:37
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    honestly something you may want to try is to seal the first bag as tightly as you can and then put that in a second bag full of water and put that into the bath so you minimize the air space and the water is more in contact with the food. – Brendan Feb 21 '13 at 00:20
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    I double bagged because my first one vacuum sealed but there was a little meat juice in the seal and I was afraid it would open up there a little and leak. I stuck the whole thing into another bag and vacuum sealed that one as well. There is no air space between the bags. The meat is corned beef and I'll be cooking it for 48 hours. I came here to find out if the extra thickness would affect my cook time. I suspected not, and am convinced by responses here that it will make no difference. Thank you, everyone! – Heather C Mar 17 '17 at 01:40

1 Answers1

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Plastics have a very low heat capacity. On top of that, the plastic in a bag is very thin. While you are doubling up on the imperfect vacuum in your bags, the effects should still be negligible.

Sean Hart
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