Does anyone have any information about the coldest temperature that is
generally possible with a 'Son of Fermentation' chiller or something
similar that circulates ice-cooled air to chill the fermentation
chamber? 'Son of Ferm.' is shown here: [url]http://tinyurl.com/5r7t4[/url]

Am curious if anyone with such a chiller has ever done, or attempted,
lagering in it, and how it turned out and what sort of problems they
might have had. I've been assuming that it is possible to drop the temp
down to close to freezing in such a chiller, but before I proceed with
modification of my chiller, I suppose it would be helpful to ask about this.

My chiller works on the same principle as 'Son of Ferm.' in that it
cools the fermentation compartment by using a thermostatically
controlled fan to circulate air from a compartment filled with ice; both
compartments are well insulated. My chiller worked very well to keep my
conical down at 70F/21C in a house with temps around 78F, but I never
bothered to try setting it to a very low setting; I never attempted to
go lower because I thought that 70F was the appropriate temp, not
realizing 65F/18C is better.

Now I wish that I would have done an experiment with my conical filled
with just water to see how low it would actually get, but it just never
occurred to me. My current thermostat isn't working, which is one
reason why I'm modifying it and therefore am considering a lower temp
range for lagering, so I can't try it now.

With my limited knowledge, I still _think_ that my chiller should be
capable of lowering the temp close to freezing (or maybe even below),
but for anyone who is thinking of making something like this and is up
to the challenge of doing a bit of calculations, here are the specs:

My chiller is constructed of a wooden frame of 2x2s, covered on the
outside with wood paneling of the sort to finish interior walls (I
believe it is called 'Wainscoat' by some); it has 1.375"/3.5cm of
styrofoam insulation on all sides and top, and half that amount
separating the two compartments. The ice compartment can hold 4 gallons
of ice as either four 1-gallon milk-jugs or eight .5-gallon
juice-containers. Those containers of ice are frozen in a large chest
freezer, and should be in the vicinity of 0F/-18C degrees.
The ambient room temp varies from about 78F/25.5C in the summer to
70F/21C in the winter; the exterior surface area of my chiller 2839
sq.inches/1.83161 sq.meters, including the base which sits on the floor
(280.56 sq.inches/.181006 sq.meters). I don't know how much heat is
generated by fermentation, and I don't know what the air-flow rate is
for my fan, but I'm sure it will complete exchange the air in a minute
or two. The interior volume is about 5,887 cubic inches/96,470 cubic cm
.... or 3.4 cu.ft./.09647 cu.meters. Of course, ice can be changed out
as frequently as needed, but normally I want to tend to it as little as
possible, and not more than once per day.

Cheers, and good brewing to all.

Bill Velek