The cause of head..

[MiranoPoncho]

What causes head in soda, beer, or for that matter other carbonated beverages? Is it a cascade of carbonic acid? If not, then what?

 

[Mark R]

Carbonated drinks contain dissolved CO2 under pressure, when the pressure is release by opening the bottle (or pouring into a glass), the CO2 is released from the solution and appears as bubbles. One of the reasons why so much CO2 can dissolve in water is because it forms carbonic acid (however, as the CO2 bubbles out of solution, the carbonic acid is converted back to CO2).

In some cases, the bubbles can collect at the surface of the liquid as a foam, or head.

The formation of foams is complex and depends on the presence of 'surfactants' which are substances that alter the surface tension of the liquid. You cannot form a head in water, no matter how hard you try, because it contains no surfactants. Similarly, relatively pure water - like some sodas - will not form a significant 'head'.

However, beer contains lots of organic substances which can act as surfactants - these allow the bubbles to form a stable foam.

Similarly, detergents/soaps are surfactants - so when added to water tend to allow foams to form if bubbles of gas are present (e.g. through stirring or shaking).

Note that some types surfactants seem to destabilise foams and are used where foams aren't wanted - e.g. laundry detergent usually contains anti-foam agents to stop the machine filling with foam, some sodas may also use anti-foam agents because people don't like 'head' on their sodas.

 

[dkozloski]

"Olde Frothingslosh" has the foam on the bottom.

 

[Leros]

Originally posted by: dkozloski
"Olde Frothingslosh" has the foam on the bottom.

A beer that contains anti-gravity particles. sweet.

What causes that to happen?

 

[dkozloski]

Google it. It's pretty interesting.

 

[MrNewt]

if you put a bit of pepper in your beer, u get great head..... For those of
you who like good head,.... like myself.

 

[dorion]

My Father salts his beer, and the head can overflow the bottle with very little salt. Hes a little crazy if you ask me.

 

[Leros]

Originally posted by: dkozloski
Google it. It's pretty interesting.

So its fake?

 

[dkozloski]

Mythical.