Malt Advocate Article
- Hello to all. I would like to answer a few of the responses to my
post regarding the Autocad drawing of the copper low wines still.
I don't have a subscription to Malt Advocate, yet anyway, I pick mine
up at a local retailer who carries it and The Wine Spectator.
I don't want to get into any copyright infringement or plagurize
anyone, but I will paraphrase what the article states.
The article is by Lew Bryson and it appears in the Volume 13, number
3 edition of Malt Advocate. The title of the article is Gleaming
Guardian: Copper Stills aren't just a pretty face. Mr. Bryson
interviewed several people for this article. Among them were Dr.
Bill Lumsden from Glenmorangie, Chris Morris and Lincoln Henderson
from Brown and Foreman, Barry Walsh from Irish Distillers, and Jim
Murray author of Jim Murray's Whiskey Bible. All these guys must
know what they are talking about since it is a fundemental part of
Anyway, to preface the article and to acknowlege some of the
speculation regarding my last post, the culprit of the corrosion and
subsequent destruction of copper stills is sulfur. According to the
article the sulfur comes from the grain itself, but it can also come
from bacterial infection of the must prior to distillation.
As the must is distilled the sulphur compounds wind up in the
spirit. The copper in the still causes the sulfur to combine with
the copper and form copper sulfate. Aside from the copper sulfate
there are other oils and fats from the grains and these combine with
the copper sulfate as well to form a black compound. According to
Lincoln Henderson, this black compound forms on the spout of the
spirit safe and he reports at the Woodford Reserve Distillery it is
quite heavy. The reason why Woodford Reserve has such a thick, heavy
greasy black deposit is because they distill bourbon and not
whiskey. As you know Bourbon has substantial amounts of corn, and
with corn comes corn oil. Chris Morris refers to it as Grunge and it
smells heavily of copper. It is also difficult to remove from your
skin. According to Chris Morris the grunge starts at the top of the
gooseneck, the lyne arm and all the way through the condensation
structure. The tail end of the Grunge eventually comes to the
spirits safe. Barry Walsh notes that this effect works the other way
in copper mining, in this case fats and oils are introduced into a
solution heavy in copper to extract the copper from the base solution.
According to Morris the Grunge is actually a polymer called ethyl
carbonate and according to him when distillers refer to EC levels in
their process it is ethyl carbonate that they are discussing, the
copper essentually cleans this out of the spirit.
Morris reports that to clean the grunge out they run a caustic wash
through the still, what results is a waste water product that is high
in zinc and copper, which cannot be processed by their local
wastewater utility. Morris reports that this caustic wash is mixedw
with spent mash and sold to farmers, where the addition of zinc and
copper is a benefit to dairy cattle.
Bill Lumsden states that the best place to utilize copper is where it
is where the hot vapors are condensing. He makes reference to shell
and tube condensors which consist of a copper column with 250 narrow
copper tubes inside. There is much more copper surface area in a
shell and tube condensor versus a worm type condensor. In his
experience he states that a spirit distilled using a worm type
condensor is much more meaty and sulfury in character than that using
a shell and tube condensor.
Column Stills are discussed in the article. Post repeal when the
distillery business was starting over from scratch a lot of
distilleries started to utilize stainless steel stills. When this
occured they noticed the immediately the difference between copper
and stainless steel stills. According to the article Seagrams did
extensive research to figure out what was going on. Essentially,
Morris states that at Jack Daniels 100% copper column stills are
used, while at Old Forrester a hybrid stainless and copper still is
used. In the hybrid still all the internal infrastructure of the
still is copper. Mr. Henderson also interjects that they also throw
a lot of copper pieces into the top of the still, basically just a
bunch of short sections of copper tubing, which lasts until it
essentually disintegrates. The scrap tubing that they put into the
still at Brown and Foreman last about 3 years and when it is
eventully removed it is very brittle, about the thickness of paper
and will crumble in your hands.
Mr. Lumsden states that the life of a still varies according to the
distillation schedule, basically saying the more you distill the more
copper dissolves. From his experience he states a 10 year lifespan
for the neck and lyne arm, For the spirits still, the main body goes
first and that is usually in 8 to 10 years.
The article closes with a few observations. In one, Mr. Lumsden
states that the still gives itself up to the whiskey. Mr. Murray puts
it more plainly and states that copper is self sacrificial and that
every time a copper still boils away it is giving part of its life to
the whiskey. Barry Walsh had the most important comment to make, he
states that modern distillers could get away with a small presence of
copper in their stills, but there is a thing of beauty associated
with large polished copper pot stills.
My observations from the article are as follows.
First these are huge stills with very thick sections of metal. The
corrosion that they are experiencing is pretty dramatic considering
the volume of product they put out and the size of the still. I
can't imagine the capital cost involve in replacing a commercial
sized still every 10 years or so.
Second, copper is only important in those areas of the still that are
exposed to vapor, that way the copper can do it's thing and the end
product will still be as good or close to what is produced in a all
copper pot still.
For a small 'hobbyist still' and the amount of mash distilled per
year, the whole problem with corrosion is insignificant. I do expect
that those who use copper in the column packing will probably have to
replace their packing every few runs or so.
My concerns were for this big monster still that everyone wanted
autocad drawings of. The cost associated to build that monster just
to have it eaten up is crazy. My opinion would be to use a stainless
steel tank and attach a copper still head to that, you'd be way ahead
of yourself. In the states a small 300 to 500 gallon stainless tank
s about $1 to $2 per gallon. I personnaly purchased a 500 gallon
horizontal jacketed milk tank from a defunct dairy farm for $225.00.
If I ever get the $$$$ to go micro-commercial I will probably use
this as either a storage tank or a maceration vessel for schnapps.
- Hello to all,
Earlier this year I paraphrased the Malt Advocate Article titled
Gleaming Guardians in which the importance of copper in still
construction was outlined and also how copper stills eventually
disintegrate due to a chemical process during distillation.
I recently viewed the Malt Advocate website and that article as well
as an article on the process used to make Jack Daniels and George
Dickell whiskeys are made.
The Gleaming Guardian article can be viewed here:
There are other articles that can be accessed as well.