For sake of the question:

  • I'm using a Sodastream brand
  • I like max carbonation
  • Normally, I use cold water from my Brita pitcher out of the refrigerator

Sodastream's FAQ states:

However, we do recommend using COLD water to achieve best results.

I suspect that best results means max carbonation, and I should use cold water. Or a conspiracy theorist could suggest their lawyers promote cold water so fewer machines will blow up. Or maybe it has something to do with flavor..

Anyway, just curious about this. I don't have the physics pedigree to know the answer.

  • I'm not sure about CO2 -- it's true for oxygen (it's the same thing that causes hot water discharges into rivers to cause fish kills), but CO behaves the other way. See antoine.frostburg.edu/chem/senese/101/solutions/faq/…
    – Joe
    Jul 28, 2015 at 17:14
  • 2
    @Joe - Solubility of CO in many organic solvents (benzene, acetone, etc.) changes direction at some point. But CO solubility in water increases with decreasing temperature, like most gases. (Your link explains why in more detail.)
    – Athanasius
    Jul 28, 2015 at 18:57
  • @Athanasius : oops ... that's what I get for skimming. (chem wasn't one of my strongest classes)
    – Joe
    Jul 28, 2015 at 19:55

1 Answer 1


Carbon Dioxide (and gases in general) dissolve more easily in cold liquids. This means that it's easier to carbonate (inject with Carbon Dioxide) your soda using cold water than warm. As your liquid heats up the gas falls out of solution creating the bubbles in your soda. Fountain dispensers usually have the water lines run through the ice hopper (or they have a cold plate) to further chill the cold water they feed to the machines for this same reason.

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