View Full Version : The Science of Washed Ice and Throat Burn

Mr Zabe
05-19-2006, 10:14 AM
Board mates I found a scientific explination for the washed ice (rinsed ice) technique of enjoying soda pop and throat burn. I found this information on the Virginia Educational Physics Website.

To keep soda carbonated, is it best to keep it cold in the refrigerator or outside in the room? Also, why does soda fizz more when you pour it over ice than when you drop ice into already-poured soda--is that just because the falling liquid has more kinetic energy? -- DG

To keep soda carbonated, you should minimize the rate at which carbon dioxide molecules leave the soda and maximize the rate at which those molecules return to it. That way, the net flow of molecules out of the soda will be small. To reduce the leaving rate, you should cool the soda--as long as ice crystals don't begin to form, cooling the soda will make it more difficult for carbon dioxide molecules to obtain the energy they need to leave the soda and will slow the rate at which they're lost. To increase the return rate, you should increase the density of gaseous carbon dioxide molecules above the soda--sealing the soda container or pressurizing it with extra carbon dioxide will speed the return of carbon dioxide molecules to the soda. Also, minimizing the volume of empty bottle above the soda will make it easier for the soda to pressurize that volume itself. The soda will lose some of its carbon dioxide while filling that volume, but the loss will quickly cease.

One final issue to consider is surface area: the more surface area there is between the liquid soda and the gas above it, the faster molecules are exchanged between the two phases. Even if you don't keep carbon dioxide gas trapped above soda, you can slow the loss of carbonation by keeping the soda in a narrow-necked bottle with little surface between liquid and gas. But you must also be careful not to introduce liquid-gas surface area inside the liquid. That's what happens when you shake soda or pour it into a glass--you create tiny bubbles inside the soda and these bubbles grow rapidly as carbon dioxide molecules move from the liquid into the bubbles. Cool temperatures, minimal surface area, and plenty of carbon dioxide in the gas phases will keep soda from going flat. As for pouring the soda over ice causing it to bubble particularly hard, that is partly the result of air stirred into the soda as it tumbles over the ice cubes and partly the result of adding impurities to the soda as the soda washes over the rough and impure surfaces of the ice. The air and impurities both nucleate carbon dioxide bubbles--providing the initial impetus for those bubbles to form and grow.

Washing the ice to smooth its surfaces and remove impurities apparently reduces the bubbling when you then pour soda of it.

Why do carbonated beverages "burn" your throat? -- TS

When carbon dioxide gas (CO2) dissolves in water (H2O), its molecules often cling to water molecules in such a way that they form carbonic acid molecules (H2CO3). Carbonic acid is a weak acid, an acid in which most molecules are completely intact at any given moment. But some of those molecules are dissociated and exist as two dissolved fragments: a negatively charged HCO3- ion and a positively charged H+ ion. The H+ ions are responsible for acidity--the higher their concentration in a solution, the more acidic that solution is. The presence of carbonic acid in carbonated water makes that water acidic--the more carbonated, the more acidic. What you're feeling when you drink a carbonated beverage is the moderate acidity of that beverage "irritating" your throat.

[ 05-19-2006, 09:20 AM: Message edited by: Mr Zabe ]

05-19-2006, 01:18 PM
That's intresting, nice find Zabe!

DJ HawaiianShirt
05-19-2006, 01:21 PM
Interesting answer, although I would more readily say that rinsed ice has water on its surface, thereby diluting the soda just a bit when poured. Therefore, the soda feels less carbonated as it goes down.

Call me a non-believer.

05-19-2006, 11:43 PM
Okay, I'm glad to read that too. Some interesting discussion of it, but I'm with DJ - not much of a believer. Actually, I've been starting to get maybe a little - I dunno, annoyed I guess - by the recent references to "rinsed ice". It seems kind of snobbish or something, and for me it would be a waste of time because I normally drink my sodas too quickly to gain anything by it. The only time I use ice with soda is when I have alcohol mixed in too. That's the only time I tend to "sip" instead of "chug" ;)


The BigTymer
05-19-2006, 11:46 PM
I guess I have to go against this thread and say I was a believer.

I was a non-believer in the rinsed ice until I tried the trick with a Cheerwine. With rinsed ice, the drink was more fizzy going down. If I didn't rinse the ice, my Cheerwine was a little flat. It was still heaven, but it's better with rinsed ice, IMHO.

DJ HawaiianShirt
05-20-2006, 02:19 PM
Wait, so is this technique supposed to subdue the soda's carbonation or enhance it?

Mr Zabe
05-20-2006, 02:45 PM
The rinsed ice procedure will enhance the carbonation of the soda pop. It's like adding an octane booster to a tank of gas. The soda pop does not use any gas to make foam/head carbonation bublles,the gas stays in the soft drink.

Party on. smile.gif

DJ HawaiianShirt
05-20-2006, 08:15 PM
Ok, so after re-reading this blurb, I now see that the argument states that by rinsing the ice, the water will melt the outer-most parts of the cubes, rounding out their edges, and make them more hydrodynamic.

I'm still a skeptic.

Mr Zabe
05-20-2006, 08:40 PM
I can see your point. It works very well for me. smile.gif

05-20-2006, 08:54 PM
Who doesn't love science?! Thanks for the interesting read.

In my opinion, it looks better over rinsed ice, and it just tastes better as well. Even if that article had disproven any difference, the perceived difference is enough for me to rinse the cubes off before tumbling them into the glass. Now, I have the science to prove to my wife I'm not crazy for doing it. ;)

Speaking of which...time for a cool refreshing beverage over rinsed ice.

05-21-2006, 04:13 AM
I think that for some of us, using rinsed ice also removes some of the unwanted flavor of the ice. If poured slowly, it also appears to preserve more of the fizz. I also shake the ice upside down before filling to remove water that might be present in the glass.

05-21-2006, 05:44 PM
I'm wondering why a person would even think to rinse their ice in the first place. The whole thing just sounds absolutely preposterous to me.

05-21-2006, 05:50 PM
Originally posted by fusion:
I'm wondering why a person would even think to rinse their ice in the first place. The whole thing just sounds absolutely preposterous to me. Then you absolutely MUST try it. There really is a difference. It's a scientifically proven fact. ;)

Mr Zabe
05-21-2006, 06:00 PM
I know that you have a pretty open mind about things. Give the rinsed ice a try. Notice how even if you do not tip your glass in the traditional 90 degree glass to bottle/can opening, that you will get a nice "headless" glass of peak carbonated,peak tasting soda pop.

I bet my reputation on it. LOL (Loose fingers Zabe LOL)

DJ HawaiianShirt
05-21-2006, 06:47 PM
I myself prefer the soda to de-carbonate a little anyway when poured into a glass.

05-21-2006, 09:45 PM
Actually, I don't put ice in my soda. I grab a cold can from the fridge.

05-22-2006, 01:53 PM
Ok here we go again.

About 20 years ago I was watching one of the morning network news shows I don’t remember what show.

They were interviewing a scientist who was trying to teach kids physics and one of his examples was the rinsed ice demonstration and explanation.

He talked about the surface tension of the ice being hard and that was why ice cracked and popped when you poured liquid onto it. That this hard surface tension caused soda to fizz up in a glass sometimes over flowing. And that first pouring clod water over the ice would cause the ice to pop and crack and bring up the temperature of the ice. Thus reducing the surface tension. So when you poured soda onto the ice it would fizz up much less and the soda would taste less flat.

I discovered that it would also remove the freezer taste. I always use ice so my ice is always fresh but some people have ice sitting in the freezer for weeks or months without being used. Every time you open the freezer door moisture and condensation collect to some extent on what ever is in the freezer. So it is collecting on the ice as well. Rinsing the ice removes this layer of frost that has tastes and smells you don’t want in your beverage even if it’s not carbonated.

Anyway that’s the story.
I recommend rinsing ice before using it in any drink. You wouldn’t use a dirty glass or eat unwashed fruit would you?

05-24-2006, 12:33 AM
Has no one here read Odyssey: Pepsi to Apple about or by John Scully or at least excerpts of it?

He specifically mentions washing/rinsing ice while being the CEO of Apple based on tricks of the trade learned while being an exec at Pepsi.

Maybe someone could look it up but I'm sure Pepsi and Coke both have loads of documentation on the issue.