I'm making my first pressurized brew using a fermentasaurus . All has been well for the first couple of days, but unfortunately one of my children had a "what does this do?" moment and opened up the spunding valve and let all the pressure out ;)

What would be the best way to increase the pressure ? I've tried googling but the only thing I can come up with is "charging" in order to bottle or transfer to a keg. I'm thinking that this would be the solution (just don't have a beer line attached)

if this is the way - I presume that the best way would be to remove the spunding valve, charge the fermenter to a certain psi/bar and then put the valve back on. I would also like to know how you guys charge - would a sodastream type gas canister be ok ?

thanks !

  • How far has the fermentation gone?
    – Kingsley
    May 6, 2020 at 6:50

1 Answer 1


You could simply add some pressure from a CO2 cylinder - as if doing a pressure transfer. Maybe take some gas from inside an emptied keg.

But really - I would not worry about it. If the ferment is still in the early vigorous stages, it will re-pressure the vessel. Even in the latter stages, carbon dioxide is still being created, and it will somewhat contribute to more pressure. Yes your beverage will not come-out pre-carbonated, but only "excess" pressure has been released, so there's no worry about oxygen pickup.

I do this all the time:

  • Think "Oooh that pressure is a little high".
  • Adjust the spunding valve the tiniest most inconsequential amount.
  • Next day, pressure is back to ambient. Grr!

Of course warming the ferment up will increase the pressure too.

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