Rock Salt and Cooling Wort?

I Read an article that using rock salt in your cooling water for your chiller can get your wort to cooler temps. Is this true and how does it work? What is the temp differences?

I use both an immersion chiller and a counterflow chiller. Both are run with tap water. How would you add salt to this water and how would this make the chiller water any colder. There is no endothermic reaction when sodium chloride is added to plain water.

It lowers the freezing temp of water.

From Jamil
A: Yes, lots of folks have tried it and emailed me that they've had great results. For example, Michael wrote:

It's been a few months since I told you that I thought the Whirlpool Immersion Chiller (WIC) was the best thing since sliced bread. I'm still using rock salt with your design for chilling to lager temps, but have eliminated that step on ales. It's plenty fast without rock salt if I'm chilling to ale temps for 5 gallon batches, especially now that it's cold in Indiana. I took a 5 gallon batch from flame out to 65 degF in 5 minutes this past Saturday. Wow!

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BUT adding salt to water will allow you to cool the water below freezing. So if you add a bunch of salt AND a lot of ice to your source water, you can run colder water through your chiller, which should make it cool faster.

arturo7 said:

It lowers the freezing temp of water.

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That much I know. That's why salt will melt ice but this method still needs to be explained.

Makes sense, thanks for the info.

BigEd said:

That much I know. That's why salt will melt ice but this method still needs to be explained.

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If you put the salted water in the frezer and get down to frezing temps then you could use it in your immersion chiller (you would need a pump of course) to chill to colder temps faster. This would be great for lagers if you live in a warmer climate like me.

Water + ice + rock salt

I think this gets you 28 deg water. Not sure about the ratio of rack salt needed.

When you put ice into water, the temperature of water will fall until it reaches the freezing point (32F). Pure water (at standard atm. pressure) cannot get any colder than this or else it would be ice!

When you add salt it lowers the freezing point of water. Therefore if your ice is nice and cold (say 10F) then with enough salt your water will be able to reach that temperature and still not freeze.

The original Fahrenheit 0-point was set by measuring the freezing point of salt water (made with Ammonium Chloride as opposed to good 'ol NaCl table salt), so in theory if you use Epson Salts you should also be able to reach this 0F temperature of water (assuming of course the ice you put in is 0F or colder)!

Very good, chips. You get a Golden Blonde on your report card.

jgardner6 said:

From Jamil
A: Yes, lots of folks have tried it and emailed me that they've had great results. For example, Michael wrote:

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The Jamil Whirlpool Immersion Chiller method does, in fact, encorporate pumping your chilling water from a bucket full of ice water. This explains how he is incorporating rock salt. Not sure I'd want to run a bunch of saltwater through my pumps and chillers, but that's the mystery solved.

david_42 said:

Very good, chips. You get a Golden Blonde on your report card.

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Thanks! I just recently watched a Nova special called "Absolute Zero" which was all about 'cold' (they used to think it was an element called Caloric). Fascinating stuff...it's a well presented and informative special that I'd highly recommend it for anyone wanting to know more about cold!