brewers like to use Corny kegs as fermentors. Although some published
articles have commented on the less-than-optimal shape of the
keg for fermenting (too tall and narrow), it is an option that
has worked well for many.
fermentation: About the easiest way to temporarily set up
a keg as a primary fermentation vessel is to simply remove the
entire gas IN valve assembly and tube. Slip a length of 1/2-in.
i.d. vinyl tubing over the threaded fitting and run it into an
If you brew
beers that typically have enormous amounts of blow-off, you can
modify a keg lid for dedicated use as a fermentor by drilling
a hole big enough for a blow-off hose. Enlarge it if needed using
a hand grinder or a file. Fittings, washers, and seals available
at your local hardware store will enable you to use a blow-off
tube that's larger than 1/2 in.
fermentation: To avoid these modifications and the cleanup
associated with primary fermentation in Corny kegs, you can use
them only for secondary fermentation. After completing the primary
in an open fermentor, I rack to an unmodified, sanitized Corny.
Every other day or so I relieve gas pressure that builds up inside
the keg by simply pressing the gas-side valve or the pressure
relief valve open for a second or two.
under pressure. For those who want to ferment under pressure
to naturally carbonate their beer, constant-pressure relief valves
can be purchased for both ball-lock and pin-lock kegs. Lager brewers
in particular will find it useful to control and maintain the
pressure in the keg as the temperature drops slowly and the pressure
increases. Typical adjustable relief valves are spring-loaded
and can be set to relieve pressures between 5 and 30 psi. They
attach to the keg's quick-disconnect fitting.
secondary fermentation is complete (or if I'm lagering), I prefer
to rack a third time to a sanitized Corny keg. This final keg
is placed in the fridge for force carbonation, cold conditioning,
and draft dispense. Every time the beer is racked from one container
to another, however, the chance of aeration and infection increases,
and you may be uncomfortable using this technique. With careful
handling, however, you won't experience any problems.
is to leave the beer in the primary a little longer than normal
before racking it to the secondary. The longer settling time will
generally result in less sediment by the end of secondary fermentation.
The secondary fermentor then also serves as the dispense tank,
with the addition of a modified dip tube (the tube that's in the
OUT side of the keg).
recommendation for this application is to cut off the bottom 3/4-1
in. of the long dip tube using a tubing cutter or a hack saw.
After filing the end to remove burrs, reinstall the tube in the
keg. The shortened tube will prevent the pickup of sediment during
dispensing of moderately to strongly flocculant yeast strains.
that works well is simply to add gelatin or isinglass finings
to the beer on final racking from the secondary to the final tank
and before cold storage. When well mixed, the finings will drop
any remaining yeast to the bottom of the keg, and even unmodified
dip tubes won't pick up the sediment.