It depends on the pH of the solution. Anything below 3 is good to use. If you live in a soft water area the solution will last longer. My water is soft and the solution lasts for a couple of months at least.
Guinness brew what they call 'essence' in Dublin which is then shipped abroad. From what I can gather this is essentially extract. The sourness referred to above is no longer really a feature of Draught Guinness as this version of the beer has been continually dumbed down for both domestic and...
Cheers guys, that's what I thought - if it's still good in the spray bottle it must still be good in the beer bottle! This means I can sanitise bottles as I go along after I drink them and clean them :)
I used my spray bottle of StarSan to sanitise several bottles last week. I didn't get a chance to bottle at the time so I put them in the fridge (with a little StarSan left in each one). They're swingtops so they are sealed. Should I be good to go with these when I bottle tomorrow?