Thawing meat in cold water

[Anna N]

I don't know if this subject has been covered before but I could not find it in a search.

I often thaw meat using the cold water method - put packaged meat in cold water changing water every 30 minutes until it is thawed. I believed it is a method approved by food safety authorities but am not sure.

I explained the method to my smug son-in-law who works in the industrial heating business and he scoffed at the need to keep changing the water. His argument was too scientific for me to explain coherently but it had to do with the mass of the meat maintaining a safe temperature even if the water was never changed.

Can one of our beloved SSBs counter with the reason why I keep the timer on and change the water ritualistically every 30 minutes?

[Kouign Aman]

Here's a stab at it, tho I'll happily defer to an official type SSB, and learn something in the process:

Doubling time of many nasty bacteria (among them E.coli) is ~ 15-18 min under ideal conditions (30C). So wash em away and keep the bioburden count low. Also, if you keep changing the water, the meat will thaw faster, since its making the water colder as they sit together.

Now granted your cold water never gets that toasty warm, so your SIL has a point - the meat is probably safe if left for longer, but it will thaw more slowly, which negates the whole point of the process.

Still, even if you go longer than 30 min, for bioburden reasons it would be good to change the water regularly. double, then double then double again ..... the bacteria count goes up fast once it starts going up. Much easier to keep it low.

[Anna N]

. . .

Also, if you keep changing the water, the meat will thaw faster, since its making the water colder as they sit together.

. . .

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Thanks. This is the part I get - that the water will be getting colder not warmer as the meat transfers its "cold" to the not quite so cold water. So adding more cold water will speed the thawing - because tap-cold water will still be warmer than the water that the frozen meat is in - up to a point. Then when the temps stabilize, you will be getting into the danger zone - above 40F - right? So, I surmize that the 30 min rule accomplishes 2 things - faster thawing and safer thawing in that you are unlikely to be monitoring the temperatures and noting when that stabilization temp occurs. Damn - I wish I had paid more attention in science class so I could be an SSB too!

[Kouign Aman]

Yup, and when you get in that danger zone, you're flushing the little buggers down the sink while they are at relatively low population levels.

[therese]

This is the part I get - that the water will be getting colder not warmer as the meat transfers its "cold" to the not quite so cold water. 

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It's actually the water transferring its heat to the meat.

[Heh, heh: heat to the meat---I sound like I'm 12]

I've never thought about it from a food safety point of view apart from the fact that you want the meat to thaw quickly, and changing the water will make it thaw more quickly. I really don't the critters in the water are going to be a significant issue.

[McDuff]

I've been taught you can thaw food under running water of not more than 70 degrees for no more than two hours.

[Anna N]

I've been taught you can thaw food under running water of not more than 70 degrees for no more than two hours.

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Interesting. I have never heard of this.

[Pielle]

Yup, and when you get in that danger zone, you're flushing the little buggers down the sink while they are at relatively low population levels.

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Actualy, you are not flushing anyting since the meat is packaged (you dont want the meat to be on contact with the water, washed out meat is not very good).

Now, I use this technique at home very often to quicl;y thaw meat from my freezer. I often start with likewarm water and change with cold tap water when it had become too cold. The whole process never takes more then 2 hours.

Keep in mind that even if some bacteria are present at the surface of the meat, they will be destroyed while cooking. Usualy, bacteria is not present inside the meat.

[A Patric]

I've been taught you can thaw food under running water of not more than 70 degrees for no more than two hours.

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Interesting. I have never heard of this.

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Actually, that is basically what the food management food-safety test in my city says. The water must be 70 F or less, and it must constantly flow strongly enough to wash away any food particulate. The illustration shows a chicken in a big pot with water flowing in from a faucet and then overflowing out the top. It doesn't say anything about a time limit.

Edited October 2, 2006 by A Patric (log)

[srhcb]

Didn't you guys see the Alton Brown episode where he melts little ice ducks by various means.

Running water was best.

SB (It's physics) (Second Law of Thermodynamics)

[Eden]

I know the running water method is supposed to work better, but I just can't take the water wastage. Some of my formative years were spent in California during a multi-year drought...

I'd be interested to know the average time difference between sitting in cool water (changed occasionally) vs. under running water.

[Anna N]

I know the running water method is supposed to work better, but I just can't take the water wastage.  Some of my formative years were spent in California during a multi-year drought... 

I'd be interested to know the average time difference between sitting in cool water (changed occasionally) vs. under running water.

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Well I wouldn't do it under running water - not at the cost of water here! I use a large bowl and let the packaged meat sit in water as cold as I can get it from the tap for 30 minutes, dump out the water and refill until the meat is thawed.

[srhcb]

I know the running water method is supposed to work better, but I just can't take the water wastage.  Some of my formative years were spent in California during a multi-year drought... 

I'd be interested to know the average time difference between sitting in cool water (changed occasionally) vs. under running water.

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Well I wouldn't do it under running water - not at the cost of water here! I use a large bowl and let the packaged meat sit in water as cold as I can get it from the tap for 30 minutes, dump out the water and refill until the meat is thawed.

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Just have the cold water continuously re-filling the bowl by letting it slowly overflow. This won't use much more water than empying the bowl every 30 minutes.

No matter what method you use, x btu's have to transfer from water to meat, the more efficiently the better. Even if you use twice as much water, but accomplish the thawing in 45% of the time, you saved water.

BTW: Use the same method for cooling hard cooked eggs quickly so they'll be easy to peel Put them in a pan of cold running water.

SB (Convection ovens use the same principle for efficient heating by moving air)

[Gabriel Lewis]

My mother always used to defrost meat this way, but never changed the water. We never had any problems. As Pielle pointed out, if the meat is sealed water-tight you shouldn't have any problems. If it isn't, you are actually stimulating bacterial growth to an extent when you change the water as you a providing them a more hospitable environment by raising the temperature.

Hair splitting aside, I don't think this merits this level of scrutiny. As long as the water is cold, I don't think you have anything to worry about.

[docsconz]

We generally don't bother changing the water either and it hasn't been a problem. I think the big question is how quickly one needs the meat thawed. Convection via running water will undoubtedly defrost more quickly.