Hello,

I have encountered a peculiar problem recently, but since I am from a not-English speaking country I would like to specify some words, as "cream" in English can be 1000 different things.

By "coffee cream" I mean that white diary liquid that people sometimes add to their coffee. There are different kinds, but normally it should be a bit thicker than milk and when beaten will produce "whipped cream".

When I make coffee I beat store-bought coffee cream, until it becomes whipped cream, and then gently place it on top of the coffee. The coffee obtains a topping, akin to that of a cake or similar confectionery.

Now, whipped cream is less dense/thinner than coffee cream so it floats above the coffee. However I have the desire to create strawberry whipped cream by using real strawberries. So far I bought some strawberries and pureed them, then filtered them through a fine strainer, so no seeds or similar unwanted product would pass through. The end product is a red jelly-like substance.

The problem arises from the fact that it is much denser and heavier than coffee and when added and mixed with coffee cream and the mixture beaten, the result is a pink strawberry whipped cream that has neutral buoyancy in relation to coffee and therefore kind of "slops" in coffee and remains completely emerged in it, while touching its surface.

Can anyone help me with that problem? I know I can just default to artificial coloring and scent, however I don't want to do that. There must be something I can add to the mixture that will make it lighter. I have tried water, milk and even vegetable oil.

As bonus questions, can anyone tell me why is whipped cream thinner than its parent cream product? I ask as a physicist and would like an educated answer and not a guess :) since nothing is added to the cream, it is simply processed in a matter that does not aerate it, I wonder why it is significantly less dense?

AYour first problem is a density issue. Fats generally have lower density that water (or in this case the liquid coffee) so in obedience to the laws of physics, a lower density mass placed on top of a higher density one will tend to float. Strawberries are solids, and while blending them makes them liquid, their density is greater than that of the cream and coffee. Mixing it with your cream makes the cream denser/heavier so it sinks.

You could change the density of the top mass and make it lighter by using natural oils or less strawberry puree OR you could increase the density of your coffee liquid-- though I doubt viscous coffee would be palatable. What you cannot do is defy the laws of physics for the sake of your strawberry cream.

#2. Cream has a high fat concentration relative to water but the water content is high enough that liquid cream will not float. When it is whipped, air is incorporated so that while the mass of a given quantity of cream that has been whipped has not changed (matter is neither created nor destroyed), the volume has significantly increased. Density = Mass/Volume. When your volume increases (as occurs when cream is whipped to double or triple its volume) the greater denominator means your calculated density for that constant mass is lower. Hence the reason why your whipped cream will float (keeping other factors unchanged).

Whipped cream is "thinner" because air pockets have been incorporated into it. Whipping (or "beating" as you put it) is the incorporation of air. I'm not sure what other explanation you want. If you allow the cream to deflate (lose air) it will return to its original liquid state. The cream did not undergo a chemical process, just physical, the same way water will freeze to ice and return to water. Ice will float in water for the same reason I mentioned. Frozen water is about 10% greater in volume than an equal mass of water. Greater volume (keeping mass constant) means lower density means it will float. Freeze a strawberry inside that cube of ice and it will sink because (i'm sounding like a broken record here) the greater mass has increased its density relative to the liquid so it will sink.

Thank you for your answer, it was quite comprehensive and scientific! :)

Since I beat/whip my cream with an ordinary mixer I didn't think it trapped air in it, since I didn't notice a change in its volume, but I know you're right, I had considered I might not be noticing it properly. :)

The problem still remains, though. As I said, I know the strawberries are heavier, etc. but I still want to use a whipped cream, made pink from real strawberries and not artificial coloring and etc. and somehow make it float. I hope there is something I can add to the mixture or some process I can perform in order for this to happen.

I have wondered if I squeeze the juice from the strawberries if it would have a better effect, but I will know when I have bought more. :) 

AYou're welcome. Olive Nation has natural strawberry extract if you want to try that.

Anyone else have an idea? The problem still persists.