[khillje]

So I brewed a Russian Imperial Stout last weekend.  Had a bit extra after the carboy was filled, so I made a little side car fermenter in a growler bottle.  As an experiment, I'd like to rack this one over before it's fully done fermenting to let the residual sugars carbonate in a swing top growler I have.  When would be the best/safest time to do this?  I'm using WLP028 Edinburgh Scottish Ale Yeast if that matters.  To be clear, I know this can be a dangerous endeavor, so I do plan on wrapping it in a bag, putting in in a box, covering it with a crate, and lowering it down a manhole (kidding), while it conditions.  It's currently been about 5 days since I brewed.  O.G. was 1.11 and the final target is 1.026.

[morticaixavier]

well it's hard to say. is this all grain or extract? what makes you think that the target FG is 1.026?

The only really safe way would be to perform a forced (or fast) ferment test where you take a sample and warm it up, put it on a stir plate, do everything you can do to make those yeast eat every bit of sugar they are able to metabolize. that FG is the real possible final FG. then figure out how much sugar you want remaining to get your target carbonation level and rack at that gravity.

I suppose alternatly you could rig up a pressure release valvle on the growler that can be set to the desired PSI for the level of carbonation you want. then as the beer ferments it will simply retain the correct level of disolved co2.

[khillje]

well it's hard to say. is this all grain or extract? what makes you think that the target FG is 1.026?

The only really safe way would be to perform a forced (or fast) ferment test where you take a sample and warm it up, put it on a stir plate, do everything you can do to make those yeast eat every bit of sugar they are able to metabolize. that FG is the real possible final FG. then figure out how much sugar you want remaining to get your target carbonation level and rack at that gravity.

I suppose alternatly you could rig up a pressure release valvle on the growler that can be set to the desired PSI for the level of carbonation you want. then as the beer ferments it will simply retain the correct level of disolved co2.

Hmmm.  That's an interesting thought!  I wonder if I just rig up something (like this: http://www.amazon.com/Control-Devices-Series-Pressure-Adjustable/dp/B007GDY3CU/) to always use an adjustable pressure relief valve during secondary fermentation.  This could get a head start on the carbonation, correct?  I usually brew 15 gallon batches so I ferment in half barrels, rack over for secondary, and just hook up the secondary to the kegerator for force carbonation.  I always brew all grain.  The target FG was just calculated from my Beersmith software.

[morticaixavier]

sure,  lots of commercial breweries ferment under partial pressure. it supposedly allows them to ferment warmer while supressesing the ester and higher alchahol formation normally associated with higher temp fermentations. It also does as you suggest and partially carbonates the beer during fermentation. The pressure setting I have heard about is 15psi but check that out for yourself.

You say half barrels I assume you mean you ferment in kegs? I would think that would be ideal

[narvin]

The target FG was just calculated from my Beersmith software.

That's not reliable, and if you're off by even a couple of gravity points you're going to get bottle bombs.

[weithman5]

instead of using a growler. do it in a 2liter pepsi bottle. first it is more likely to hold pressure, second if it fails it will not likely be catastophic in that it will not likely shatter.  and if so it is not glass going all over.  yes it is clear, but to protect it from light but just throw it in a bag, under a crate and in a manhole...