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Cider Digest #1217
Subject: Cider Digest #1217, 21 April 2005
From: cider-request@talisman.com
Cider Digest #1217 21 April 2005
Forum for Discussion of Cider Issues
Dick Dunn, Digest Janitor
Contents:
Re: Grafting timing (Terence Bradshaw)
Re: Cider Digest #1216, 17 April 2005 (Chaad@aol.com)
RE: Alcohol Determination ("McGonegal, Charles")
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Subject: Re: Grafting timing
From: Terence Bradshaw <tblists@pshift.com>
Date: Mon, 18 Apr 2005 08:14:13 -0400
Do it now. I assume you are talking about cleft grafting in the field? I
do it any time it's warm enough to wirk without gloves on, from late
February on. Much after green tip or tight cluster is getting late. I
hope you collected your budwood before break and kept it in a cooler, it
needs to be dormant. The rootstock however can be actively growing.
Hope that helps,
Terry B
>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.
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Subject: Re: Cider Digest #1216, 17 April 2005
From: Chaad@aol.com
Date: Mon, 18 Apr 2005 10:19:08 EDT
Andrew writes:
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
Ebuliometry (which, to the best of my understanding, measures the difference
between the boiling point of the cider and that of water) is less cumbersome
than distillation and only slightly less accurate. As far as being more or
less tricky, it is a fairly straightforward procedure that gets easier with
practice. I have found the procedure outlined on the internet, as well as in a
number of winemaking books. High levels of residual sugar can play havoc, but
winemakers I know that do this on a regular basis can get accurate results in a
rather short time. My guess is that someone with basic chemistry knowledge
and enough free time to practice could become proficient (instructions for use
at http://www.stpats.com/manuals/Ebulliometer.pdf). The problem is that
ebulliometers are not cheap either (although as the price of easier testing
methods comes down used models are coming available).
Regarding the chemistry behind the Reflectoquant's alcohol test, the manual
says "Reflectometric determination after enzymatic reaction with alcohol
dehydrogenase." Explanation of this is beyond my limited chemistry capability.
Most of the test strips had a shelf life of less than 2 years on the 50-strip
package (at $75-125US per package). I could probably use that many free sulfur
strips, but others would expire before they were used.
Regarding my measurement of alcohol using specific gravity, I take the
reduction in specific gravity and multiply it by 1.25 (1.095-.995 during
fermentation would be 12.5% alcohol (.1x1.25), less my personal and
unscientific .75% fudge factor gives me 11.75% alcohol). Not pretty,
but it seems to get me fairly close. Once again, harder to do when it
gets into blending.
Has anyone trid a vinometer? It is a six dollar glassware piece that looks
similar to an eyedropper. It says it measures "cappillary action".
------------------------------
Subject: RE: Alcohol Determination
From: "McGonegal, Charles" <Charles.McGonegal@uop.com>
Date: Tue, 19 Apr 2005 14:40:28 -0500
I will second Andrew's opinion that measuring the alcohol by
distillation followed by hydrometry of the distillate and pot is harder
that you might think.
I don't practice the technique very often in my day job as a chemist,
but I think I'm moderately familiar with how it should go - and it
doesn't work out that easily in practice. I have a variac and heating
mantle that I've scavenged - those help control the process. But they
are hard for the kitchen-chemist to get.
I find that it is very to easy to get incomplete recovery of the
alcohol. One leaky joint, and you're done. Now, it may not help that I
tend to run with a [unnecessary] fractionation column - but getting
repeatable results is hard. I think you can use readily available
hydrometers at the finish - but not to get within 0.1% ABV.
Now, I do practice a distillation-related method when tracking the
progress of our cherry port fermentation. That product starts with a
whole fruit fermentation that is halted by addition of spirits. I'm
more concerned with tracking the residual sugar than the alcohol. I
take a sample and microwave it in a Nalgene beaker until it's good and
de-boozed. Than I let it cool and make up the lost volume with water in
a volumetric flask then read the solids with a refractometer. Easy to
practice and easy to get the equipment.
The Wurdig equation (or the variation that I have) will also spit out
the solids content. I haven't gone back to check how well the solids
numbers from each method match, but it might be an easy way to adjust
the Wurdig number - or at least have an idea that it's off.
Come to think of it, the solids component of a dry cider will be very
low to measure by hydrometry or refractometry. About 1.3 Brix in the
example Pat Littrell gave [calcuated amount]. Perhaps that number would
be useful in correcting other estimating techniques - like the change in
gravity method.
Charles McGonegal
Aeppeltreow Winery
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End of Cider Digest #1217
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