Copy Link
Add to Bookmark
Report
Cider Digest #1215
Subject: Cider Digest #1215, 14 April 2005
From: cider-request@talisman.com
Cider Digest #1215 14 April 2005
Forum for Discussion of Cider Issues
Dick Dunn, Digest Janitor
Contents:
Fermentation complete (plittre2@bigred.unl.edu)
Alcohol determination ("Dave and Jen Halliday")
Re: PH meters (Claude Jolicoeur)
Re: Alcohol determination by refractometry (Claude Jolicoeur)
Measuring alcohol (Chaad@aol.com)
Send ONLY articles for the digest to cider@talisman.com.
Use cider-request@talisman.com for subscribe/unsubscribe/admin requests.
When subscribing, please include your name and a good address in the
message body unless you're sure your mailer generates them.
Archives of the Digest are available at www.talisman.com/cider
----------------------------------------------------------------------
Subject: Fermentation complete
From: plittre2@bigred.unl.edu
Date: Tue, 12 Apr 2005 16:50:07 -0600 (CST)
I may be at the most elementary level of any of your readers but I have been
reading the Digest for well over a year now and I have come to trust its
contributors in their cider expertise. I am working on my Master's degree with
cider as my topic of research. I hope to develop an acceptable cider using
(don't laugh) standard/dessert apples. I might add,I have no experience. So
therre's a little background.
I have been monitoring the fermentation with a refractometer. No cultivar
would ferment to completeness as I have read in your column. The Brix reading
was never lower that 4.25 (Starting around 13)even after 2 months. Finally
realizing what an odd coincidence it was that none of the apple varieties would
ferment below that level, I tested the refractometer with a standard 20% sugar
solution--it was very close. Using a hydrometer to test each cider that had
showed a 4.25 Brix indicated a gravity of .950. Further testing with reagent
strips for glucose revealed that there was no glucose present.
Do you think there is something wrong with the refractometer? Or could there
be other soluble non-sugar compounds present in the cider that could be
effecting the reading? Thank you for any direction you can give me.
Pat Littrell
------------------------------
Subject: Alcohol determination
From: "Dave and Jen Halliday" <info@brownsnout.com>
Date: Tue, 12 Apr 2005 16:17:02 -0700
> Subject: Alcohol determination by refractometry
> From: Andrew Lea <andrew_lea@compuserve.com>
> Date: Mon, 11 Apr 2005 21:40:29 +0100
>=20
> Three of of us (Gary Awdey plus myself and Martin Harris in=20
> the UK) have
> been looking at the possibilities for measuring alcohol in=20
> cider without
> complex lab equipment. The official methods are direct GLC or
> distillation followed by some direct measurement of alcohol in the
> distillate such as density or refractometry - but neither of these can
> be done in the back kitchen and require proper chemical lab facilities
> or contract analysis at say $50 (=A325) per sample.
Actually the Australian company Monash Scientific has the distillation
procedure explained online and it does not seem that complex.
Here is Monash's web page for general Wine analysis:
http://www.monashscientific.com.au/PricesMenuWineAnalysis.htm
They offer instructions for Acidity/pH, Sulphur Dioxide, Volatile
Acidity and Alcohol.
Check the tutorials for the step-by-step instructions and additional
links to other sites.
Monash does glass-blowing but there are other sources for the glass - I
have been very happy with Cynmar Scientific for our supplies.
http://www.cynmar.com
You will need some way to measure specific gravity calibrated to %v/v
(ABV) but a simple floating hydrometer and a correction table will work
well.
The Monash website also gives an overview of Chemical Analysis after
Distillation - using Potassium Dichromate to convert the Ethanol into
Acetic Acid and then using titration to determine the concentration.
More accurate but a bit more labwork.
Dave Halliday
Brown Snout Farm and Cidery
http://www.brownsnout.com
------------------------------
Subject: Re: PH meters
From: Claude Jolicoeur <cjoli@gmc.ulaval.ca>
Date: Tue, 12 Apr 2005 23:18:50 -0400
In CD 1214, Julian Temperley wrote:
>For the last twenty years we have triturated
>with iodine/starch to give us an acid level. In our case we are looking
>for higher than .35. It is not the same as ph , but near enough ,
>cheap, quick and fool proof. You can buy the chemicals from any wine
>supplier.
Julian,
For the benefit of all of us, could you elaborate a little more on your
technique for acidity measurement? For my part, I use titration with sodium
hydroxide, but I have never heard about a technique that uses starch and
iodine.
Thanks,
Claude Jolicoeur, Quebec.
------------------------------
Subject: Re: Alcohol determination by refractometry
From: Claude Jolicoeur <cjoli@gmc.ulaval.ca>
Date: Tue, 12 Apr 2005 23:52:27 -0400
In CD 1214, Andrew Lea wrote:
>Three of of us (Gary Awdey plus myself and Martin Harris in the UK) have
>been looking at the possibilities for measuring alcohol in cider without
>complex lab equipment. The official methods are direct GLC or
>distillation followed by some direct measurement of alcohol in the
>distillate such as density or refractometry - but neither of these can
>be done in the back kitchen and require proper chemical lab facilities
>or contract analysis at say $50 (£25) per sample.
Andrew,
I would tend to disagree with you (sorry about that, but I think it is the
first time since I read this digest)... I feel that a small distillation
equipment can be built or bought for quite cheap. I am thinking in
particular about the lab equipment we used for the chemistry courses while
in high school (quite a while ago), but I still remember a small glass
still that probably wasn't very expensive as they let 15 year old boys use
it... Then if you boil a measured quantity of cider until a third or half
of it has evaporated and condensed (this would probably be enough to insure
all the alcohol has evaporated, but would have to check), measure the
volume of condensed liquid and its alcohol content with an alcohol
hydrometer and compensate for the volume difference, you could end up with
a quite accurate estimate of the alcohol content of your cider.
So, let's say, for example, we boil exactly 500 ml of cider, and get
exactly 200 ml of condensat at 15% alcohol, then our cider was 15*200/500 =
6% alcohol.
I think this could easily be done in the kitchen, and all the equipment
needed would be:
Small still (probably no more expensive than a refractometer, or can be
easily built)
Alcohol hydrometer (easily available for about 20$ in a wine supply shop or
in lab equipment supplies)
A couple of precision cylinders for measuring liquid volumes
And the added bonus would be a good shot of eau de vie...
Claude
------------------------------
Subject: Measuring alcohol
From: Chaad@aol.com
Date: Wed, 13 Apr 2005 10:00:30 EDT
At one winery with which I am familiar, they used a hydrometer for much
of the alcohol measurement in what they labelled as apple cider (but in
actuality we would call wine--the U.S. govt. draws the alcohol line higher
than this board seems to). The law in the U.S. gave a 1.5% margin of error,
and measuring the sugars with a hydrometer was accurate enough to hit the side
of this rather large barn. It worked quite well if the wine was fermented
to dryness and resweetened, but for a fermentation that was stopped early
it was less accurate.
There was an ebulliomer at the facility, but user error limited the
effectiveness of it. It is an extremely acurate method of measurement (in
fact, it is the method the govt. uses when they audit a facility), but it is
a pricey piece of equipment that takes some familiarity and chemistry knowhow
to do properly (a level that has escaped me since the old college chem days).
Before they broke down and bought an alcolyzer (accurate to a couple
hundredths but cost comparable to a compact car), they bought a reflectometer.
This machine did very well, which was confirmed by comparison to the brand
new alcolyzer. The reflectometer (made by a Merck subsidiary under the name
Reflectoquant--http://vinquiry.com/feature.htm) is costly, about $550US for
the box and another $1.50 each for the test strips, but it also measures
acidity (total and titratable), sulfur (free and total), sulfurous acid, pH,
and a host of other things. All told, the wine kit ran close to $700 for the
machine and all the test strips they needed. It worked great on white and
apple wines, but because it measured the color change in a reactive strip,
it was not effective on darker colored wines, even after sample dilution.
Still a little pricey for the size of my hobbey, so I will keep measureing the
sugars with a hydrometer. I have run some of my meads through the alcolyzer
and found that my calculation was usually within a percent and always high,
so I just went back to using the hydrometer and subtracting .75%. Ciders I
was a little closer, but still high.
------------------------------
End of Cider Digest #1215
*************************
