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I have researched a bit about the topic of "large crystal prevention" when freezing and thawing food. So far I have learned, that in order to prevent the formation of large crystals, which is what damages the texture of food, you need to minimize the time the food spends around 0°C. Which means you need to freeze it to -18°C as fast as possible and when thawing bring it to room temperature as fast as possible. I am talking about a home context here, not commercial.

I have come up with the following routine, which seems to incorporate most home tricks, in order to optimize for few large crystals:

When freezing:

  • vacuum seal the food in a sous vide bag, as flat as possible
  • put it in an ice bath
  • circulate the water in the ice bath with a sous vide stick
  • After say 20min put it in the freezer

When thawing:

  • Figure out the max temperature you need the food to be (say the temperature, at which it is going to be served, or if it is going to be cooked, below the target temperature)
  • Put the vacuum bag in a preheated water bath and circulate the water at this temperature

However, I would like to know, how much of this effort is actually worth it? Is vacuum sealing much better than zip bags? Is ice bath much better than simply putting the food in the freezer at room temperature? Is the additional step of using a circulator (which apparently does reduce the time greatly) really worth it?

Are there any case studies or side by side experiments on this subject? Is it possible to taste the difference?

I know that freeze burn is bad, so I do avoid standard zip bags already in favor of vacuum seal bags, but I am not so sure about the other stuff?

Edit:

It seems the claim, that defreezing quickly is as important as freezing quickly is not universally accepted, I base my belief in this on the following video:

https://www.youtube.com/watch?v=r5-akBNZouM

the longer something takes to freeze and defrost, the bigger the ice crystals...

at 0:23

user1721135
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    As best I know, rapid thawing is a food safety issue, not related to the issue of damage caused from freezing. And there are other alternatives to what you're doing ... eg, put it in the fridge before you freeze it. – Joe May 17 '19 at 10:49
  • @Joe good point about the fridge. But aren't ice crystals formed around a certain temperature? So it wouldn't matter "in which direction" you are going, when you cross it? That's how I understood it, but it did surprise me. – user1721135 May 17 '19 at 11:16
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    What is your goal? There is quite a bit of real science on this subject. For example: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4662221/ – moscafj May 17 '19 at 12:22
  • @moscafj just trying to figure out, if the methods mentioned make sense or if it is a waste of time. Often times science says that something makes sense, but the home implementation of it is not good enough in order to achieve any result. – user1721135 May 17 '19 at 12:45
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    @user1721135 : no, because ice crystals only grow as you're freezing, not as you're thawing. (unless something is *really* wrong with how you're thawing). We want to avoid large ice crystals, and they'll grow if we freeze slowly. (fast freezing will result in more, finer ice crystals). To compare, you might want to try making ice cream without stirring/dashing, and compare the graininess. – Joe May 17 '19 at 13:45
  • I am basing my claim on videos like this one, from serious eats: https://www.youtube.com/watch?v=r5-akBNZouM note how it says "time to freeze and defreeze". There is another video from Jamie Oliver, where he mentions defreezing speed as well. – user1721135 May 17 '19 at 19:23
  • @user1721135 In addition to the initial freezing, ice crystal growth can increase over time in the freeze with temperature fluctuations. You may rapidly freeze the item to minimize the issue, then leave it there for month putting warm items in and letting in warm air and undo your careful initial freezing. – dlb May 17 '19 at 22:00
  • @dlb that's a good point. My freezer display always shows -18°C, don't notice any fluctuations, but over a longer period of time it is probably bound to happen at some point – user1721135 May 17 '19 at 23:33

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This sounds like a lot of time and effort, that, for home use, might not be worth it. Freezing as quickly as possible is generally recommended, but even with an ice bath first, you are not going to be able to freeze quickly enough to make that much of an impact using a home freezer. At home we have more control over how a product is thawed. For example, see this question/answer. I would say that rapid thawing is probably where you lose quality, though I will admit that I often use the circulator to thaw meat that I forgot to remove from the freezer a day in advance. Would I notice quality difference in a side-by-side comparison? Maybe, but sometimes convenience outweighs a slight difference in the final product.

moscafj
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  • My understanding is, that quick thawing is actually better, as mentioned in this video: https://www.youtube.com/watch?v=r5-akBNZouM or it least, that's how I understand it. – user1721135 May 17 '19 at 19:27
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    @user1721135 I didn't see where Kenji said that quick thawing is "better"...only more convenient. I will also point out that "quick" thawing on the counter (using Kenji's method) is also different from "quick" thawing in, say, a microwave, which is probably worse for quality. – moscafj May 17 '19 at 21:58
  • "the longer something takes to freeze and defrost, the bigger the ice crystals..." at 0:23 . If you think about it, if it is about a particular temperature, near the freezing point causing the problems, why would it matter in which direction you are going when crossing that line? The point is to cross it quickly either way. But I am not 100% on this, love to see other sources on this. – user1721135 May 17 '19 at 23:31
  • @user1721135 https://cooking.stackexchange.com/questions/92738/why-slow-thawing-is-the-best-way-to-defrost-a-chicken-flavor-wise – moscafj May 18 '19 at 02:26
  • Yes, that seems to contradict what Kenji said. I wonder what he meant and why he said it. – user1721135 May 19 '19 at 08:15
  • Kenji is about most convenient, with least impact on quality and safety. The science is about an objective discovery of phenomena. I don't disagree with Kenji's method. I do think there is a point where you can defrost too quickly, and that will impact quality. As I mentioned above, in a microwave, for example. – moscafj May 19 '19 at 11:05