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Cider Digest #1216
Subject: Cider Digest #1216, 17 April 2005
From: cider-request@talisman.com
Cider Digest #1216 17 April 2005
Forum for Discussion of Cider Issues
Dick Dunn, Digest Janitor
Contents:
Alcohol measurement issues (Andrew Lea)
Reflectoquant etc. (Andrew Lea)
Re: Cider Digest #1215, 14 April 2005 (RELve@aol.com)
Grafting timing (Evan C Owen)
Re: Fermentation complete (Marc Shapiro)
Re: Alcohol determination by refractometry (Andrew Lea) (Michael Faul)
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Subject: Alcohol measurement issues
From: Andrew Lea <andrew_lea@compuserve.com>
Date: Fri, 15 Apr 2005 20:35:36 +0100
Pat Littrell wrote:
> 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. 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.
There is nothing wrong with your refractometer It is the *alcohol*
which is the soluble non-sugar compound that gives the apparent 4.25
Brix reading!! That's why you cannot use a refractometer directly to
measure the loss of sugar - you should use a hydrometer for this.
Apparent Brix 4.25 and SG 0.995 (the SG of 0.950 you quote is presumably
a typo!) gives a value of 8.2% alcohol (by the Wurdig wine equation).
- -------------------------------
Brown Snout wrote:
> Actually the Australian company Monash Scientific has the
> distillation procedure explained online and it does not seem that
> complex.
Claude Jolicoeur wrote:
> I feel that a small distillation equipment can be built or bought for
> quite cheap. .... 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,
Thanks for your perspectives and I'm sorry I have to disagree with you
both! I have done the distillation method myself many times in a lab -
it may not be complex in principle but it's quite unsuitable for
untrained hands in a kitchen! It is difficult to get 100% recovery of
the alcohol into the distillate unless you use special and expensive
glassware (known in the UK as an Excise condenser). Large errors can be
introduced by poor distillation technique and alcohol vapour is easily
lost. The accurate measurement of the distillate density by hydrometer
then requires absolutely accurate temperature control and a specially
calibrated and expensive alcohol hydrometer (or an accurate
temperature-controlled refractometer or a Parr density meter or a
density bottle and 5 place analytical balance or some other similarly
very expensive device), It's OK if you have a trained technician doing
it daily but it's not the sort of thing for someone doing it on a casual
basis just a few times a year! In fact real analytical labs hardly use
that method at all now, because it's so laborious and GC is so much
speedier.
> And the added bonus would be a good shot of eau de vie...
And you'd need it!!
Andrew
- --
Wittenham Hill Cider Page
http://www.cider.org.uk
------------------------------
Subject: Reflectoquant etc.
From: Andrew Lea <andrew_lea@compuserve.com>
Date: Fri, 15 Apr 2005 21:06:37 +0100
Chaad wrote:
> 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
> 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.
In the UK we have a 1% margin on ciders and it seems that measuring
'loss by SG' and multiplying by a fudge factor (typically given as 7.5) is
almost as good as anything to give alcohol levels to meet that.
Certainly it's very cheap! Not so helpful if ciders are blended, watered
or whatever, since then you can lose track of what's going on. So a
method for finished product would still be handy.
> 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).
Re my other posting on this topic ... is ebulliometry more or less
tricky to do reliably than distillation and density measurement?? I've
never used an ebulliometer. They are widely available (even in the UK).
The German speaking wine world seems to think highly of them
> 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.
When the wine Reflectoquant was first introduced (5 years ago?) I don't
believe it did alcohol - I think that's a newly added kit. I wonder what
the chemistry is - maybe dichromate oxidation as mentioned by Brown
Snout (and as formerly used in police breathalysers)? The ability to measure
other things could be a great help. Often with these kits the test
strips come in packs of 50 or so but only have a short shelf life.
> All told, the wine kit ran close to $700 for the machine and all the
> test strips they needed. Still a little pricey for the size of my
> hobbey,
Agreed!
> 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.
Do you mean just that? You measure the loss in SG, multiply by the 7.5
fudge factor and then subtract 0.75% from the final alcohol level?
Andrew
- --
Wittenham Hill Cider Page
http://www.cider.org.uk
------------------------------
Subject: Re: Cider Digest #1215, 14 April 2005
From: RELve@aol.com
Date: Fri, 15 Apr 2005 23:37:10 EDT
I am likely even further back than the freshest of the beginners, now in my
second year of trying to rebuild an old orchard in So. Ore. (while still living
in So. Calif. As one can expect, the possibilities are endless, as are the
potential heartbreaks...
Thus leading to my question for the group: I am currently raising a new batch
of apple/pear trees down here in So. Calif.-about 15 for now. They are all
neatly planted in peat pots and should be transeferred within the next 18 months
to their final living quarters-a 1/4tr. acre bordering Waldo Rd. in Josephine
Co., Ore. (about 5 miles north of the California border). After two weeks of
unbelievably typical So. Cal. weather, (ranging from 70 to 90 degrees F), I
have found that three particular trees have simply refused to show any signs of
coming out of dormancy: Theilersbirne, Blakeney Red and Gelbmostler...strangely,
these three are all pear varieties. Now up in Ore., I am more likely to
lose the apple trees while the pears seem to have their own haven. Has anyone
else had any experience with these three particulars and would you say they are
simply slow to break or have I possibly done something wrong that I might
"right" before it's to late?
Otherwise, I have also been working with some experimental seed stock from
Cornell University & Philip Forsline-a truly nice fellow. Thus far, I've had 90%
ave. germination with 18 month old seeds on four separate groups (not named,
only numbered). My hope is to raise these seedlings for three years, clone
scions from their parents to 50% of them and try cloning other varieties to the
rest-looking for any possible improvements in apple growing/survival in the "Wal
do" area. Note: Pear trees were recorded as having been grown as far back as
the 1850s when this was a thriving mining community and some wild pear trees
still survive there today-even after it was mined away through hydrolics ( so
we're talkin' two inches or so of soil in some places).
many thanks in advance
Robert e Lee
<~a transplant~>
------------------------------
Subject: Grafting timing
From: Evan C Owen <fnon@juno.com>
Date: Sat, 16 Apr 2005 20:27:42 -0400
Any advice on when the optimal window is to topwork seedlings with cider
scions? I'm at silvertip now and gittin' antsy. Some rule of thumb
relating to apple or another tree (i.e. shablow bloom) would be
appreciated.
Evan in Mass.
------------------------------
Subject: Re: Fermentation complete
From: Marc Shapiro <mshapiro_42@yahoo.com>
Date: Sun, 17 Apr 2005 15:38:51 -0400
plittre2@bigred.unl.edu wrote:
> ... 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?
There is something wrong with your refractometer, or the formulas/tables
that you are using. If there were non-fermentable solids they would
affect the hydrometer reading. Since the hydrometer is definately
showing a complete fermentation, and your reagent test strips also show
no glucose then it is safe to say that fermentation is complete.
Since you get an accurate reading from the refractometer when using a
20% sugar solution I would tend to think that the error is actually in
the formulas, or tables, that you are using to convert the refractometer
reading to brix. Perhaps the tables/formulas are not accuarately
accounting for alcohol present in the finished cider, hence the
accuarate reading for a sugar solution, but an inaccuarate reading at
the end of fermentation, when alcohol affects the reading of the
refractometer, just as it does that of a hydrometer.
Marc Shapiro
------------------------------
Subject: Re: Alcohol determination by refractometry (Andrew Lea)
From: Michael Faul <mfaul@rabbitsfootmeadery.com>
Date: Sun, 17 Apr 2005 18:00:38 -0700
I have access to an Anton Paar Alcolizer and the results I get are
consistent with the results I get using my ebulliometer.
Mike
Red Branch Cider Co.
www.redbranchcider.com
www.rabbitsfootmeadery.com
>
> My reason for posting is to raise awareness of the issue and to ask if
> there's anyone out there who is currently using the SG/RI technique for
> measuring alcohol in cider, what equations are they using to compute the
> results, and how accurate is it compared to the 'official' methods of
> alcohol measurement? Is anyone using alternative techniques such as an
> ebulliometer with any success for alcohol measurements cider?
>
> Andrew Lea
------------------------------
End of Cider Digest #1216
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