Boston Apothecary

this is a cautionary tale… any advice would be appreciated.

for quite a while i have dreamt of the idea of bottling high pressure sodas in champagne bottles within a restaurant scenario. ginger beers, sparkling lemonade, sparkling versions of still wines, or maybe hibiscus soda that resembles the structure of prosecco.

so far carbonated with yeast, but only ended up with sulfurous yeasty brut sodas (but the carbonation was flawless!).  i’ve tried to come up with manifolds like the tap cap or perlage system to force carbonate single bottles, yet have had little success. this all led me to attempt more traditional keg to bottle force carbonation.

the first problem was to develop a proof of concept experiment using only water.

to bottle something resembling champagne the beverage would have to be 60 psi at room temp (though i’ve heard some champagnes can top out at 80).  in the fridge, with the same amount of dissolved gas, the pressure will be lower but how low exactly is tricky to figure out (i can’t find any tables that explain the relationship…).  my fridge is cold, maybe just above freezing in the high 30’s.  what do i have to set the pressure at if i want it to expand to 60 at room temp?  to figure this out i thought i’d simply carbonate the keg to 60 psi at room temp.  easier said than done.  it takes multiple days for the water to absorb the gas.  i actually don’t think i ever got to 60 on multiple tries.  one time i actually had a leak and found the entire just filled gas cylinder empty.  gauges will say you are at 60 but those are just measuring the pressure in the head space and not accounting for what is going on in the liquid.  after wasting a full tank i thought i’d just estimate a number in the fridge so i went with 40 psi at fridge temp.  i didn’t let it warm up to room temp to see what it hit, but i’m pretty sure i got to 40 and it would make a nice drink.

now we had to get the water out of the keg and into a champagne bottle.  many factors can thwart this being done.  my discharging tool was the highly regarded “blichmann beer gun”.  i was hoping that it would scale up the the pressure and do the job.  the beer gun applies no “counter pressure” and claims it doesn’t need to because it’s design reduces so much turbulence relative to other designs.  (youtube videos show it working really well for beer)

i thought i would lower the pressure and push the highly carbonated liquid at a much lower pressure out of the keg. unsuccessful.  you could see at the very beginning of the hose that the gas was coming out of solution (we started at 5 psi maybe).  gas came out of solution until we turned the pressure up to the 30’s.  apparently counter pressure is critical.  we probably need everything colder as well.  the rig is large and probably needs a colder fridge and a large ice bath.  probably two stock pots of salted ice which is more than i keep in the house.

at 30 psi we were able to keep the gas in solution, but we had not even pulled the trigger yet.  the liquid immediately starts to lose gas as it rockets out the valve.  30 psi is a lot of pushing power.  i surmise that if there was anything dissolved at this pressure it would foam to death.  a solution would be to concentrate the flavoring,  dole it out to the bottles, and freeze it to the bottoms.  after getting the water in the bottles the frozen flavoring will warm up and dissolve.

the soda water we were left with wasn’t bad, but my bottling plant isn’t ready for prime time.

what i think i really need is a bottling apparatus that does counter pressure really well. i think i’m going to have to try a traditional design.

i’m also going to retreat to ginger beer which is bottled at a pressure slightly above beer.

you live and you learn…