Hmmm. Wouldn’t the higher viscosity of sugar-water make the bubbles grow more slowly? After all, the carbon dioxide molecules have to diffuse across quite a distance of liquid to arrive at the bubble surface. If the water is made more viscous, it should slow the CO2 diffusion and slow down the outgassing.
“Less fizz” has to involve either fewer bubbles or bubbles which grow more slowly. I bet it’s the second one.
Philster - on a similar subject, adding sugar to a cup of VERY hot coffee just removed from a microwave causes it to boil up and over the edge of the cup. I always assumed that this was because adding sugar LOWERED the bp of the coffee???
Have I been mistaken all these years??? Bummer…
bbeaty - is that along the lines of the ‘impossible beverage’, i.e. a guinness & coke?? Always a good one to ask for if you suspect the bartender is new in the job…stand well back.
Ah, that explains the strange poster that was in the local burger joint back when I was a kid. It had a bunch of ski bunny types with steaming mugs, and a title “DR PEPPER, TRY IT HOT!”
Actually I found several “nucleation site” substances empirically while messing with superheated water & microwave ovens. Superheated water acts very much like warm cola.
http://amasci.com/weird/microexp.html#coffee
Any substance which carries microbubbles into the superheated coffee-water will trigger some explosive boiling. For instance, hot tap water would do it, but re-heated tap water would not. Put a little dish-soap into hot tap water, wait a few minutes, and you’ll see a layer of white foam appear as the microbubbles rise to the surface. Let some hot tap water stand around for awhile and it loses its microbubble load, and it will no longer trigger boiling when dumped into superheated water.
Dry wooden coffee-stirrers (or toothpicks) will make your superheated water boil. They’re like the “boiling stones” used by chemists to prevent explosive boiling. New clean glassware has too few scratches to offer trapped microbubbles.
Sugar crystals don’t “wet” instantly, so they carry an air film. Same with salt, sand, powdered creamer, and dry frosty ice cubes. (Wet ice cubes won’t trigger cola fizz.)
Try this: pour a lot of salt into a little water, stir so as much dissolves as possible, then dump it into cola. Big explosion of fizz. Then pour some salt into water, stir, let it stand for a half hour, then dump it into cola. FAR less fizz. By letting it stand you did nothing to the salinity, but you did let all the microbubbles rise to the surface. (I haven’t tried it, but I bet if you kept stirring for the entire half-hour, the microbubbles would still be there, and the stuff would still make the cola fizz.)
thanks bbeaty - that’s one of life’s little mysteries cleared up !!
Next time I’m at Muppet Labs (aka my kitchen…) I’ll have to try a few of these for myself.
hutchley
In a similar vein (as the OP), there is a huge difference between clear plastic cups and white plastic cups. I believe that the white plastic cups have a rougher surface, and thus provide more nucleation sites than the clear variety, where a rough surface would be a whole lot more visible.
It is almost impossible to pour beer in a white plastic cup! It will foam and spill over at once if you’re not carefull.
Flat diet soda: It’s not my imagination and I’ll have to learn to live with it (unless someday the artificial sweetener that replaces sugar is replacing sugar on a 1 to 1 volume basis, and has a similar affect as sugar, creating very similar boiling points between diet and regular. Until then, diet will fizz out faster than regular soda)
Thanks, all!
Ludovic and bbeaty, sorry for the nit-pic here (granted what I am talking about here is the 1 time in a billion billion billion and would always be overcome by simpler methods, aka dirt, but I will defend myself to the bitter end) but depending on the relative sizes of the molecules, nucleation can be considered microscopic. Also, yes, to come out of solution, there is a needed interface, however that does not exclude the interface creating itself, aka a brand new bubble. Pressure rerelated to bubble radius is:
P1-P1 = 2y/r
As you take r to 0 you see that the pressure difference required goes to infinity. Since there is not likely to be a non-chaos induced event like this, nucleation “must” occur for a bubble to form, which we are agreed upon. Of course that is assuming that y (surface tension) remains constant.
The question is what may act like a nucleation site. Since it is an assist to breaking the infinite pressure barrier, anything that creates a situation in which vapour formation occurs, leading to the formaion of a bubble can be defined as a nucleation site. In addition, the surface tension gives us some room to play. If an object (molecular or otherwise) i introduced that will lower y, this decreases the pressure required. Thus, a sugar/sweetener molecule that can act through molecular/ionic/anything else forces to seperate the water into gaseous phase would be a nucleation site.
That being said and argued, the most common reasons for nucleation are what you stated, air is trapped and diffusion of the gas into the air blah blah blah.
And good call bbeaty on the viscosity affecting diffusion and it also comes into play with my bubble formula. Although the question is, isn’t the mass transfer of the eddying soda resulting from the pouring greater than the rate of diffusion?
Back to the OP with Popup, are the injection molds different for your cups? Also is the type (number) of plastic different? I am wondering if you had a clear #2 X type cup versus a colored #2 X type cup if there would be a difference…
Diet soda has FAR less syrup than regular soda – the calibration on diet taps in a soda fountain is significantly different.
The things you learn working at Pizza Hut.
Diet sode has no syrup, so that would qualify as far less.
Philster, the stuff that is mixed in with the water and the carbon dioxide is still commonly called “syrup” even if it contains no actual sugar.