Is the formation of bubbles in cream foam a result of the gas or the structural properties of the liquid? If I tried to whip cream in a vacuum, would it form a foam or remain liquid?
You are whipping air into the cream, which forms bubbles. Without the air, all you are going to get is a mist of tiny droplets.
Why would you get mist? Surface adhesion works equally well in a vacuum.
Well, it’s probably complicated because the cream is going to be boiling and outgassing vapor during your experiment. If I had to guess, it’s that you’d probably end up with some kind of dessicated sponge-like material. The boiling process would probably make the whipping superfluous (unless you’re into that kind of thing).
It depends on how hard you beat it…
If you had a bowl of cream in a vacuum you wouldn’t be able to whip it because the water in the cream would quickly boil off and you’d be left with butter and curds.
Maybe a better experiment would be to put a flexible wrap over the cream so no air touches it, and whip it from below or use one of those magnetic stirrers.
So then the question is, would the cream expand from water vapor bubbles formed from the water in the cream during whipping, or does it require the incorporation of air bubbles? And I’m pretty sure you’d churn the cream into butter before you got much foaming.
OK, assume you reduce it down to a pressure and temperature just above where the cream would boil off. I’m mainly curious about whether the process of foam formation is dependant on the properties of the gas or liquid.
The gas is required to keep the structure from collapsing.
This is my thinking too.
The liquid is responsible for forming the membrane that would look like a rubber balloon in miniature. That membrane might have some strength to hold itself up - especially as the whipped cream nears butter consistency - but it mostly it’s like the balloon. Without air pressure inside the bubble it would collapse flat on itself.
In a way, though, the vacuum might actually make it easier to foam. The bubble is held up by the difference in air pressure inside vs outside, and it only takes a small difference to inflate the foam. Since the water in the cream will vaporize in a vacuum, there is a ready source of gas for the whipping process. The question in my mind is whether stable bubbles can be formed before you lose all your water to vapor.
Now I’m picturing whipped cream infused with lint and dust.
You keep asserting things and then providing no evidence for it whatsoever. Why would gas be required to keep the bubble from collapsing? In 1 atm, the gas pressure inside and outside of the bubble is equal, in a vacuum, the gas pressure from inside and outside the bubble is equal.
In 1 atm a reduction of a bubble’s volume increases the pressure, preventing it from collapsing. In a vacuum the reduction of a bubble’s volume has no effect and bubbles won’t even get to form. Very basic physics.
No… the gas pressure inside the bubble is higher than the pressure outside. It might be a very small difference (like a soap bubble) or a very large difference (like a rubber balloon), but at the very least, the pressure inside must be sufficiently high to both support the weight of the bubble against gravity and to resist the surface tension of the liquid.
Huh? Is it possible you are confusing vacuum with zero-gravity?
Ah, interesting, thanks. That makes sense.
I’d suggest use the canned variety, and do the whip-et at the end.
particularly fun in zero gravity, but not so much in the vacuum.
If you had some already-whipped cream and you began lowering the pressure, would it start expanding?
IANAPhysicist, but I know cream.
It seems to me that the cream would very quickly begin to separate into it’s component parts. Cream is quite anxious to do this at the slightest provocation. It is also quite elastic once you warm it up by whipping, so balanced atmospheric pressure is not going to hold up the bubbles. The sides of the bubbles would be pressing inward toward collapse.
More importantly, the round shape of the bubbles is formed by the air getting trapped and then rising and pushing equally in all directions. What you would be forming is just layers of cream (like folding in a meringue) which would re-form immediately because there is no air in between. So all that stirring is just going to speed up the separation of the water from the fat.
The OPs plan sounds to me like a much faster way to make butter.
I dunno about that, but here’s what I pictured happening:
:DYes. Here’s a chocolate covered creme puff in a vacuum bell. https://www.youtube.com/watch?v=-VOs5oTrVnQ