Can beer get head in a vacuum?

The bubbles are not from air, it is carbon dioxide released from the liquid. It is kept in dissolved in the beer (or soda, same process) by pressure until the can or bottle is opened.

I don’t know how a vacuum would affect that. I am guessing the lack of pressure would make it foam faster.

No, because beer has no penis.

The answer is yes…and it would probably be mostly foam. As @Call_Me_Jay said, the bubbles are not from air but from the carbon dioxide in the liquid (a by-product of fermentation). When you open a bottle of beer, you notice it usually foams a little. That is because you have changed the pressure on the liquid and some of the gases are coming out of solution. When you pour a beer into a glass, you are stirring it up which creates more change in pressure, releasing more gases. If you were to open a beer in a vacuum, it would likely spew foam everywhere, leaving almost nothing in the bottle.

To simplify this and use real numbers let’s figure the beer is nice and cold. – near 0 C. Also let’s figure beer is about the same as water – because that is the only data I could find easily. Let’s start out at standard pressure and reduce the pressure in the thought experiment.

Given those assumptions from the Engineering toolbox Solubility of gases in water we see that a liter of water/beer will hold 3 grams of CO2. From the same source we see that the density of CO2 is about 2 grams /liter at room temp and pressure.
So a liter of beer will hold 1.5 liters of CO2 at standard pressure – 1 atmosphere. (That was a surprise to me.)
Now let’s start reducing the pressure. Go to half an atmosphere. Using the universal gas law we see that the CO2 will expand to 1.5/ 0.5 = 3 liters
Now go to one tenth of an atmosphere. The CO2 will expand to 1.5/ 0.10 = 15 liters.
Now go to 1/100 of an atmosphere. The CO2 will expand to 150 liters.
The vacuum of space is less than one trillionth of atmospheric pressure (100 nPa) so the CO2 would expand to more than a trillion liters.
That is a billion cubic meters or a cube one km on a side. That is a lot of head.

I’ll leave it to someone else to figure out how much surface area a liter of water can cover when spread to a single layer of molecules.

Beer suddenly exposed to a vacuum would pretty much explode.