I thought it was just me, until this trend was confirmed by several other people tonight. Mountain Dew Code Red and Pitch Black seem to not get as cold as other sodas when kept in the fridge just as long or longer than them. Why?
Have you tested it with a thermometer? Your senses can be fooled by a lot of other factors. I’m not saying there can’t be differences in how fast things of the same specific heat cool but I doubt if they are significant.
I think Mountain Dew is more carbonated than other soft drinks. Perhaps that has something to do with it?
Ah. The POWER of suggestion.
Do a controlled scientific experiment with identical glasses, thermometers, cans at room temperature overnight, placed in fridge using gloves for the same period of time, revomved with gloves, opened, and poured into glasses with thermometers in place. Let set at least three minutes and read thermometers.
Compare readings. Prediction: Not much difference? Not enough to be perceivale?
Mass is perhaps the easiest and least complex possibility. Do you have a dieter’s scale that weighs in grams?
I’m not really familiar with these beverages, but The Mountain Dew Code Red I’ve seen has always been in plastic bottles–most often roughly 16 oz (give or take) that seem a little different from generic bottles. I’d suggest weighing the bottles with their soda, then the contents and bottles separately.
Mountain Dew may have (for example) more dissolved sugar than many other sodas, making it denser. If, as another poster has suggested, it is more carbonated, its bottles may be a bit thicker of differently shaped. Increased mass per surface area or thicker plastic (which is a fair insulator of heat) would explain the phenomenon.
Personally, I doubt higher carbonation could be the direct physical cause. A more carbonated beverage would usually release more CO2 in the first minutes after opening. The extra CO2 would absorb heat while coming out of solution, and carry it away. Since we can only drink soda after we open the container, you’d probably feel a more highly carbonated soda was colder on the tongue, even if it were the same temperature in the bottle. Are you saying that the intact bottles cool more slowly, or the soda inside the the bottles?
[You can confirm that ‘de-carbonation’ absorbs energy by checking the solubility of CO2, which like most gases, dissolves much better at low temps. At lower temps, dissolving is favored because it gives up energy, at higher temps, there is more energy to drive the reaction in the other direction.)
Instead of confirming that it cools more slowly with hourly in-fridge measurements, you might try taking long chilled (days) bottles out of the fridge and measuring the temperatures side-by-side as they warm. Absent any complex chemistry (unlikely), the Mountain Dew should also warm more slowly.
Could the warmer-seeming sodas be in a different zone of the refrigerator than the colder-seeming ones? The temperature inside my fridge at least is not uniform and if that’s the case with yours that could account for difference in cooling time/warmer-cooler sodas.
Another possible factor is thermal conductivity. Put a piece of wood or plastic and piece of metal of identical size in the freezer overnight. Take them out and measure their temperatures at the same time. Then touch them. The metal will feel much colder because it conducts heat from your fingertips much faster than the wood does.
Actually, Mountain Dew around here (Nevada, Utah, California, Arizona) is less carbonated than almost any other soda.