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08/20/2008
Here is a nearly completed draft of an article I am
writing for Zymurgy. I am hoping to get feed-back to
help me finish it up.
“We Seek the Grail...”
My home brewery begs the question as to when enough is
enough. Do we really need aeration stones, two-zone
plate heat exchangers and steam kettles to turn out a
drinkable six-pack of suds? We all know the answer,
and yet for most brewers there is an allure in
gadgetry. We make the best with the pot in hand while
dreaming of the two keggles in the bush. And for some
of us the quest for that next great thing is driven by
a nearly crusader’s passion.
Much of the quest for gadgets is driven by a desire for
control. Timers, thermometers, hydrometers and scales
have all become standard gadgets for producing
consistent beer. There are, of course, practical
limitations and reasonable individuals who will tell
you control is an illusion. Yet the Siren’s song of
precise control is hard to ignore.
Conical fermenters have become popular in recent years
in part because of their beneficial design and the
control it provides. A primary benefit is the ease of
separating the yeast from the beer. In the case of
traditional carboys and buckets you need to transfer
your beer into a secondary container, which means
cleaning and sanitizing each piece of equipment that
comes into contact with the beer. With a conical, you
can simply draw off any break, trub or yeast you wish
through a dump valve. Likewise, samples for evaluation
are easily taken through a racking valve. Further, some
conicals are designed to hold pressure, which helps
prevent airborne contamination and allows for sanitary
transfers using CO2 pressure.
An additional benefit of many conicals is stainless
steel construction. Stainless steel resists
scratching, and staining. It is inert and so it will
not carry flavor into a beer. It is impermeable to
light, odor and oxygen and will not break when exposed
to heat, cold or an unintended trip to the floor.
Conicals come in a variety of sizes, which allows for
single vessel fermentation. This size benefit can also
be a disadvantage when it comes to cooling. While
smaller vessels fit in refrigerators, larger ones
require other solutions. Many strategies, such as the
use of cooling coils and cold rooms, are successfully
used for chilling conicals. I initially installed
internal cooling coils that, while effective in
cooling, presented a cleaning nightmare.
Jacketed, conical fermenters, or uni-tanks as they are
commonly known, are standard fare in the micro-brewing
industry. Their stand alone design allows for
individual control and conservation of valuable floor
space. The cooling set-ups are generally straight
forward and sometimes amazingly simple. Thermo-couplers
in each fermenter signal digital temperature
controllers to turn circulation pumps on and off to
circulate chilled glycol through fermenters’ jackets to
control the product’s temperature. The better
commercial conicals have zoned jackets, including
jacketed cones. Less expensive models may have only a
single, small, jacketed area. But in every case the
goal is control, simple and effective.
I recognize the idea of a jacketed conical fermenter
for home brewing is ridiculously over the top. It is
neither necessary nor practical. But honestly, since
when has practicality really been part of the equation?
“The Practical Brewer” indeed!
The quest for my grail of gadgets began with the
winning of an on-line contest. The prize was a gift
certificate from Toledo Metal Spinning, the
manufactures of the conical hoppers we all crave. My
prize was sufficient to purchase two large hoppers.
Yet as I explored the choices an idea was born: “What
if two could become one to create a single, perfect,
jacketed fermenter?” The idea was obviously
impractical, but we’ve been through that.
Toledo Metal Spinning manufactures 16 different
hoppers, ranging in volume from .1 to 51.1 gallons.
PDF files are available for each hopper, providing
specific dimensional information. Only a handful of the
company’s hoppers are useful as fermenters, but two of
their models are perfectly suited for my design. The
dimensions of the 21 gallon model, TMS201014, allow it
to nest inside the 24.1 gallon model, TMS221014, with
less then a ¾” gap between their walls. This gap is
perfect for circulating glycol around the fermenter to
regulate its temperature. Unfortunately, the standard
outer diameters (OD) of the vessels’ upper rims are not
compatible for nesting. Fortunately, the company
offers a variety of custom modifications.
Specifically, they are able to trim the inner hopper
(TMS201014) so its rim OD matches that of the outer
hopper (TMS221014). Problem solved, obsession
begun.
My design is relatively simple. (reference image #1) A
½” stainless coupling is fitted and welded into holes
cut in the sidewall near the top and the bottom of the
larger hopper. These will serve as the jacket’s inlet
and outlet ports through which coolant will be
circulated. (reference image #2)
Next, the bottom few inches of the outer hopper is
removed to allow the tip of the inner hopper to
protrude. This allows for a relatively simple union to
be made at the bottom of the jacket. The matched upper
rims are then welded together, creating a complete seal
around the upper lip. (reference image #3) This weld
must be ground smooth to allow a proper seal on the
finished fermenter.
Finally, a donut shaped plate, a metal ring of sorts,
is cut to fill the space between the bottom of the
exterior jacket and the outer wall of the interior
jacket where it protrudes. This ring is welded in
place, creating a seal at the bottom of the jacket.
(reference image #4)
There are numerous designs for legs and stands. My
fermenter is supported by three stainless pipe legs
which have been welded to the outer wall. Consideration
should be given to the height of these legs, as well as
their stability. A friend, welder, and fellow
homebrewer, Bret Haskins, constructed a bracketing
system to mate the round pipes with the cylindrical
body of the fermenter, providing exceptional strength
and stability for the legs. (reference image #5)
Another major consideration is the lid and seal of the
fermenter. This is an area where you ingenuity needs
to shine as you determine the system that is best
suited to your needs and budget. Toledo Metal Spinning
sells both flat and domed covers. Other companies,
such as Blichmann Engineering and More Beer,
successfully utilize gaskets and clamps on their
systems. My fermenter uses a Blichmann gasketed top
with a wrap around barrel clamp. (reference image #6)
This system is air-tight and very satisfactory.
A drawback of my jacketed design is that it does not
allow for the use of the type of separate, rotating,
racking arm preferred by many conical owners. To
compensate for this, a sanitary T is attached to the
bottom of the cone. (reference image #7) A racking tube
is inserted through the vertical arm of this T, while
the horizontal arm serves as the dump port. The
racking tube has a T tip to help prevent clogging
during fermentation. Its length is such that it rises
a few inches into the cone, allowing the beer to be
racked off the settled yeast and trub. Whatever
racking system you choose it should be removable for
easy and thorough cleaning.
My fermenter is cooled with chilled glycol supplied
from a commercial glycol chiller. This chiller was
originally used to cool draught beer lines and contains
a compressor, heat exchanger, glycol reservoir and
digitally controlled pump. This chiller was given to me
and while they are available commercially, they may be
beyond the budget of even the most gadget obsessed
brewer. Other systems can be developed, utilizing
freezers, pumps and digital temperature controllers.
In my system the glycol chiller pumps glycol into an
Igloo cooler that serves as a secondary reservoir.
(reference image #8) The chiller recirculates chilled
glycol through this secondary reservoir, keeping it at
a set temperature as determined by its digital
temperature controller. A second pump, controlled by a
Ranco Digital Temperature Controller (model
ETC-111000-000) with a thermo-coupler in the fermenter
(reference image #9), recirculates this glycol through
the fermenter’s jacket as needed to maintain the
desired fermentation temperature. In cold weather, the
glycol chiller can be turned off while an immersion
heater is utilized to warm the glycol for
recirculation.
By and large my fermenter is complete; although I am
sure I will find other ways to tinker with it soon
enough. I will probably insulate the exterior and play
around with clean in place ideas. But for now I plan
to simply enjoy the fruits of my quest and I dream of
my next conquest.
So, what does anyone know about digital flow meters
anyway?
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