I keep my fridge VERY cold. Mostly because it essentially contains drinks, or things you cook. Thinks you cook the temperature isn’t so important, whilst practically any drink that a sane person would be putting in the fridge is best as cold as possible.
Occasionally this leads to icing. And I noticed today that the frozen part of my Irn Bru (a carbonated soft drink popular in the UK) was both colourless and tasteless - well, it tasted like ice, to be exact.
This is usually the case.
So how do they give ice lollies flavour? The only thing I can think of is carbonation has something to do with this, but yet I am sure I remember making coke lollies with my mother when I was younger.
I’m not sure what happened to your beverage, but normally, if a flavorful liquid is frozen, the resulting ice tastes like a really cold version of its unfrozen self. Eg/ frozen orange juice tastes like orange juice.
So popsicles start as flavored water, the same stuff if thaws out to if you forget it in the sun.
ETA: IIRC, cold can affect taste bud sensitivity, so a grape flavored drink will freeze to a grape flavored ice, but may not taste quite as grapey, but pretty close.
Liquids freeze at different temperatures - in fact, you can distill alcohol by freezing the water, and pouring off the still-liquid alcohol. As I remember from making orange juice popsicles (or ice lollies, if you prefer), the tip (since they were made upside-down) was always the tastiest. In fact, it was entirely possible to suck all the flavor out of the popsicle, and be left with very faintly flavored ice, which suggests to me that the water remained frozen under conditions where the orange-juiciness didn’t. I’m no expert, but I’d guess that because you’re fridge isn’t significantly colder than freezing, your Irn Bru is freezing slowly enough that the water turns to ice, and whatever’s giving it flavor remains liquid. Eventually, if you kept removing the ice that formed, you’d end up with Irn Bru Concntrt.
I think it also depends heavily on how well the flavored stuff is suspended in the water to begin with. I remember during our many “let’s freeze this today” experiments that some of the more syrupy beverages froze in a gradation of flavor even worse than the orange juice. I guess the syrupy flavor component congealed and sank to the bottom more, so that part of the ice tended to have the biggest flavor whallop.
Yeah, it’s pretty common for things to freeze so that you have relatively pure water ice with a higher concentration of everything else. Given the chance, the everything else will tend to migrate out of the freezing water.
Most of my interesting experiments have to do with alcohol.
I drank a frozen beer once without waiting for it to fully melt and was pretty surprised to get the same alcohol kick you’d expect from a shot of hard liquor. Apparently, the 1/4 or so of the can that was unfrozen contained almost all of the alcohol of the whole can.
I always think of granite when I’m looking for analogies to this behavior. Granite that supposedly cooled quickly has small crystals that may not be visible to the naked eye. Granite that we think took longer to cool has very large crystals that are visible even from a distance. All of these crystals formed from relatively homogeneous magma; the longer they had to cool, the larger the crystals and the greater the amount of separation.
If the OP’s fridge is super-duper cold but not actually set to freeze might produce a more gradual freeze which would probably be more amenable to the “migration” dracoi mentions too.
Commercially made ice lollies/popsicles seem to be very different from the ones you can make in your own freezer. As runcible spoon mentions, it is possible to suck all the flavor out of a home-made one, and be left with just ice. You can’t do that with a shop bought one. What is more, the ice in the latter is very different, softer than regular ice and composed of little needle shaped crystals, like fibers all laid in parallel. How do they achieve that? I imagine it is either due to the use of special additives, or a carefully controlled rate of freezing (very fast? very slow?), or both, but I do not know. Does anyone here know?
The two things I find when making home-made icy poles (“popsicles”) with ordinary drinks are that they taste less sweet when frozen, and are too hard.
I overcome this with adding sugar and gelatine (I guess if you had the right flavour you could just use flavoured jelly crystals and get both at the same time). This works well for juice and cordial. I haven’t tried carbonated drinks, maybe they separate more easily or maybe it was because the whole thing wasn’t yet frozen.
Was your Irn Bru in a bottle or a can? Presssurisation could also be an issue. A friend of mine used to make “coke granitas” out of cans of coke in the freezer - you had to leave them just long enough so they didn’t quite explode, and then when you opened them you would get a slushy-like mix of ice and coke - quite delicious! I never noticed whether the ice bits were pure ice or coke-ice though.
It probably has something to do with speed of freezing as well. Your refrigerator is only just barely below freezing. This causes the liquid to freeze slowly and allows ice to separate from the flavor and color. Also, pop-sickles are relatively small and have a high surface area to volume ratio. This also increases the thermal transfer and the speed of freezing.
This is why a chemist trying to purify a compound with recrystallization tries very hard to get crystals to form slowly.