Excuse me!! You DID miss my point!! And "what" info did I give that
is incorrect? If you think the ATF's "leeway" of 1.5% will allow you
to "label" a wine at 13.8% that they can pull off the shelf and
"measure" at 14.01% you are sadly mistaken!! As I said, if you
repeatedly do that, they WILL take away your permit! There is ZERO
tolerance for "crossing" tax brackets!!

Your argument about differences between barrels or batches is
meaningless in a commercial winery. We generally blend or "cuvee" from
multiple barrels and check the alcohol on the blend for the COLA. And
we, and everyone else that I know, use an ebulliometer because we
believe it to have the best accuracy for the buck!! When I calibrate
my ebu to atmospheric pressure with water, I can get repeated
measurements on a given sample within +/- 0.2% over the course of an
hour or so. In these days of longer hang time we're seeing more and
more wines in the high 13's. If I got multiple readings of 13.8 or
13.9 with the ebu, I would send a sample to ETS labs before committing
to the number I put on my label, and pay the "right" tax.

Hence, my original response to Maurice!

Charlie

Excuse me!! You DID miss my point!! And "what" info did I give that
is incorrect? If you think the ATF's "leeway" of 1.5% will allow you
to "label" a wine at 13.8% that they can pull off the shelf and
"measure" at 14.01% you are sadly mistaken!! As I said, if you
repeatedly do that, they WILL take away your permit! There is ZERO
tolerance for "crossing" tax brackets!!

Your argument about differences between barrels or batches is
meaningless in a commercial winery. We generally blend or "cuvee" from
multiple barrels and check the alcohol on the blend for the COLA. And
we, and everyone else that I know, use an ebulliometer because we
believe it to have the best accuracy for the buck!! When I calibrate
my ebu to atmospheric pressure with water, I can get repeated
measurements on a given sample within +/- 0.2% over the course of an
hour or so. In these days of longer hang time we're seeing more and
more wines in the high 13's. If I got multiple readings of 13.8 or
13.9 with the ebu, I would send a sample to ETS labs before committing
to the number I put on my label, and pay the "right" tax.

Hence, my original response to Maurice!

Charlie

Hi Joe,

Thanks for bringing this up!! When I recieved my lab training I read
about such procedures, but we only "practiced" ebulliometry. Zoecklein
mentions a few methods involving distillation (into a Kjeldahl flask?)
of the sample but I don't see "proof and tralles" mentioned. I assume
it is a distillation followed by hydrometer? This would be a special,
close range hydrometer?? My problem with hydrometers for "accurate"
readings is one of "interpretation" of the meniscus ... often no more
accurate than a whole division on the scale. With a mercury
thermometer (as on my ebulliometer) I can interpolate down to a half a
division easily! ... which is 0.05% alcohol. Another difference is the
"efficiency" of a refluxer (ebulliometer) vs a distillation coil. I
use ice water in my refluxer and I believe it returns nearly 100% of
the EthOH to the sample. I don't think a distillation coil is as
efficient. Anyone?

Anyway, any info you have on the method you bring up would be
interesting!!

Thanks,

Charlie
PCW

Hi Charlie,

Both hydrometry and ebulliometry have an uncertainty in the range of
0.3% when measuring alcohol by volume as I recall.

You are right on in your post, a Proof and Tralles hydrometer is
calibrated for measuring proof and ABV (Tralles). You can also get
narrow range Tralless, they make the most sense for wine. I have seen
10 to 15% ABV narrow range hydrometers.

The biggest problem using this method is getting a good seal between
the boiling chamber and the condenser, efficiency doesn't matter since
you distill most of the sample over. It's not like your refluxer in
that sense, but if the seal is bad you can lose the alcohol and get
false low readings.

(By the way, this should NEVER be used to distill for consumption - at
least in the US if anyone is thinking about that. It's not only
illegal it's stupid. Liquor is cheap, impisonment and loss of the
house and everything in it is pretty expensive. It's illegal for more
than tax reasons, there are byproducts of distillation that are
poisonous present using this procedure, it is NOT for consumption. I'm
not going to discuss that further, it's just the reality of the
situation.)

You can get a good hydrometer from Kessler and a whole boiling chamber/
graham condenser setup is usually around $100 US if you are ok with all
that in glass, it can break pretty easily. Out the door it's probably
more like $200 US if the stands, standard volume flask or graduate and
burner need purchased too.

You can use the residue for a disolved solids test if desired too, so
it's a 'multi-tasker'.


Anyway, all you are really trying to do is remove the dissolved solids
in this method by leaving them behind. The main interferences are
sugar, (just like your ebulliometer) and a high acetic acid level.

You start with a standard volume of say 200 ml at 60F, boil most of it
over and restore the volume to 200 ml at 60 F with distilled water and
measure with the special hydrometer.

As to reading the meniscus on the hydrometer, I agree most people can
go wrong when it comes to reading them, it's almost an art.

Unless specifically told otherwise by the manufacturer, the correct
procedure (an abbreviated form of what NIST does follows):

* ensure the hydrometer is very clean and at the same temperature as
the fluid under test, (usually 60 F is prefered)

* measure the temperature of the fluid under test

* spin the hydrometer as it is lowered into the fluid under test.

* ensure no bubbles adhere to the hydrometer

* once it stabilizes, lower the eye below the fluid level and look
straight across, raise the eye level until the ellipse formed by the
fluid boundary just disappears, you are now at the level of the fluid
boundary.

* read the hyrdometer as it passes through this level and apply
temperature corrections if necessary.

(NIST has a PDF on hydrometry available on the web, it does a better
job of explaining this.)

I have a set of DuJardin Salleron hyrometers that specify reading the
top of the meniscus; it's odd but they are precision instruments so I
do what they say with those.

Zoecklien et al and Margalit both have pretty detailed procedures in
recent publications as you mentioned. There is a company in New
Zealand that has a pretty good description on the web too, it might be
Monash or Monarch Scientific, something like that.

HTH.


Joe

pcw wrote:
Hi Joe,

Thanks for bringing this up!! When I recieved my lab training I read
about such procedures, but we only "practiced" ebulliometry.
Zoecklein
mentions a few methods involving distillation (into a Kjeldahl
flask?)
of the sample but I don't see "proof and tralles" mentioned. I
assume
it is a distillation followed by hydrometer? This would be a special,
close range hydrometer?? My problem with hydrometers for "accurate"
readings is one of "interpretation" of the meniscus ... often no more
accurate than a whole division on the scale. With a mercury
thermometer (as on my ebulliometer) I can interpolate down to a half
a
division easily! ... which is 0.05% alcohol. Another difference is
the
"efficiency" of a refluxer (ebulliometer) vs a distillation coil. I
use ice water in my refluxer and I believe it returns nearly 100% of
the EthOH to the sample. I don't think a distillation coil is as
efficient. Anyone?

Anyway, any info you have on the method you bring up would be
interesting!!

Thanks,

Charlie
PCW