Why do Guinness bubbles go down instead of up?

TThe bubbles at the center rise rapidly until they get to the top, just below the head (the "froth"). In doing this, they have pushed and pulled the surrounding liquid with them. At the top, this liquid flowing upwards hits the surface and flows outwards towards the edges of the glass.he bubbles at the center rise rapidly until they get to the top, just below the head (the "froth")

Let's start at the point where you have just poured your pint of Guinness, and it is starting to settle. At the inside surface of the glass, the bubbles are touching the walls of the glass and they experience drag - just in the same way as you can feel if you slide your finger along a glass surface. At the center of the glass, the bubbles are not touching the walls, and are free to go up: this is what bubbles of gas really want to do when they are in a liquid, as we are used to seeing.. In doing this, they h

http://www.chem.ed.ac.uk/guinness/why.htmlave pushed and pulled the surrounding liquid with them. At the top, this liquid flowing upwards hits the surface and flows outwards towards the edges of the glass.The bubbles at the center rise rapidly until they get to the top, just below the head (the "froth"). In doing this, they have pushed and pulled the surrounding liquid with them. At the top, this liquid flowing upwards hits the surface and flows outwards towards the edges of the glass.