ice bath chilling?

In the General Sous Vide Questions Forum
Is ice bath chilling mandatory for sv cooked food before putting into freezer if freezer is very efficient and rapidly freezes food?

6 Replies So Far

An ice bath just chills the food very quickly and effectively. If you have a freezer or cooler that works very quickly (such as a blast chiller I'd assume) then the ice bath is not needed. Most freezers do not chill that quickly though due to the differences in heat transfer in air vs in water.
Jerry, in an ideal world we'd all have blast chillers or loads of ice floating around the kitchen, not often the case in a UK kitchen, maybe the warmer temperatures of the US mean ice is more available in the kitchen.

One of the key points about sous vide is that water is a much better medium for heat transfer than air, this applies equally to heating and cooling. What we are trying to do is minimise the length of time that the cooked food is in the biological 'danger zone'. Unfortunately, in terms of bacteriological risk, its not just about the cooling medium; the shape of the food makes a difference as does the overall weight and whether the food has been pasteurised, how hygienic your prep was, plus probably a host of other factors.

For my own practice, if I am doing a large batch, or single large piece of sous vide cooking I will try and use ice, for a couple of chicken breasts cooked to pasteurisation I'll cool in plenty of cold water, then refrigerate or freeze.

The decision reflects your individual attitude towards bacteriological understanding and risk.
I may have devised a better way. Water conducts heat away better than air but metal does it even quicker. I now put a metal (baking) pan and a cast iron hamburger press in the freezer in anticipation of quick cooling the s.v.ed food. After, I put the pouch on the tray in the freezer and place the hamburger press over it to push it onto the tray. The combination seems to be working very well to quick freeze the cooked food.
Water conducts heat better than air by a factor of 10! If you do not have a lot of ice available, use the ice packs that are re-freezable, the smaller the better as they have more surface area. The goal is to take the food out of the "Danger Zone" (41F - 140F) as quickly as possible, with SV, proteins (meats, fish, eggs, etc) we really need to get to 36F. because temperature above this will allow anaerobic pathogens spores to vegetate(GROW), so you need to store then below that. If your refrigerator does not have an area in that range, only hold your items for 3 days or less, otherwise freeze them.
Yes, TonyB, in the US refrigerators are often equipped with ice makers built into the freezers. To keep the ice from collecting food odors and becoming useless for use in beverages, it's necessary to come up with reasons to empty out the ice that has been collected from time to time. Using ice to chill sous vide packages is a fine reason to empty out the ice tray. If we didn't have these kind of excuses, we'd just have to throw away ice every few days.
I had a restaurant meal last night that instantly brought this question to mind. The Chinese sweet and sour pork was seasoned too lightly, and the freshness of the pork was shown to be just less than optimum. The first sensation had was that the flavor was absent from the meat. It struck me that I've noticed this before -- meats that don't yet taste unpleasant from lack of freshness may nonetheless lose a bit of meatiness. You scratch your head over this, realizing that well cured meats taste more meaty, but the truth is that the desirable flavors of the meat fade do to the action of biology. This suggests that there is a flavor advantage to quickly chilling your sous vide meats before storage in the refrigerator...

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