Why crystals/ Particles encourage bubble creations in beer/ stout?

[Mystral]

Why do certain particles/ crystals, e.g. sugar, encourage the creation of bubbles in beers and stouts when dissolving?

 

I have noticed that when sugar was dropped into stout/ beer, it creates a surge of bubbles (released from gas in beer) to the surface. However, there were 2 other observations made:-

 

1. dropping non-soluble particles, e.g. silica or sand, do not create this effect.

 

2. dropping certain soluble particles, e.g. coffee, do not create this effect.

[Tartaglia]

This isn't really my field of expertise, but it is probably different change in Gibbs free energy of adsorbtion on the surfaces. You will have the eqm

 

CO2(aq) <> CO2 (adsorbed on surface) <> CO2(g)

 

and the position of eqm will depend on the strength of intermolecular interaction between the CO2 and the solid surface

 

There may also be a kinetic effect too

[Hephaestus]

Also,

 

mechanically, a bubble cannot form without a surface to form on. In order for a bubble to stabilise and grow, it needs to build up a certain internal pressure. Any solid object, and especially one with sharp corners will catalyse / initiate and stabilise the formation of a bubble. The stronger the adhesive forces between the surface and the bubbling liquid, relative to the cohesive forces of attraction within the liquid, the easier to bubbles will form.

[Mystral]

How then do we determine (from millions of available small particles) which crystal/ particle can create this effect, and which will just sink to the bottom without encouraging further bubble formation?

 

Does the chemistry of the particle affect this at all, and if so, what/ how?

[Rocket Man]

i think it's because the sugar is more soluble than the carbon dioxide,

silica will provide more surface area to form bubbles on, coffee might not be soluble enough to replace the co2 in solution.

i've done a few home experiments with high pressure and air, i managed to dissolve air in water and create the same sort of thing as soda and beers. all it is, is the gas is dissolved into the liquid under high pressure. high pressure makes gasses more soluble, so when the pressure is released, the gas will slowly come out, and highly soluble materials act as catalysts to speed up the gas coming out of solution.