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Cider Digest #1837
Subject: Cider Digest #1837, 3 January 2014
From: cider-request@talisman.com
Cider Digest #1837 3 January 2014
Cider and Perry Discussion Forum
Contents:
Re: Conical fermenter ("Charles McGonegal")
Inexpensive spectrophotometry for cider testing (Andrew Lea)
Variable capacity tanks (WhetstoneCiderWorks)
Addendum: Inexpensive spectrophotometry for cider testing (Andrew Lea)
year-end note (Cider Digest Admin)
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Digest Janitor: Dick Dunn
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Subject: Re: Conical fermenter
From: "Charles McGonegal" <cpm@appletrue.com>
Date: Tue, 31 Dec 2013 10:33:20 -0600
That's one of the reasons I like the Transtore IBCs. Other than a couple of
gallons to rinse out the drain, I can rack to a fraction of an inch of the
lees top before they start to shirt. They are essentially flat bottomed. The
IBCs claim to be free draining - but I've never had a level enough floor to
see if it was true - I use a food grade squeegee on a pole to sweep out the
dregs.
Charles McGonegal
AEppelTreow Winery & Distillery
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Subject: Inexpensive spectrophotometry for cider testing
From: Andrew Lea <andrew@harphill.co.uk>
Date: Wed, 01 Jan 2014 14:24:19 +0000
On 31/12/2013 15:13, Bill Bevis wrote:
> A few years back, there was a question on the list about testing for TA,
> and Andrew Lea said that spectrophotometers were sometimes used for this
> kind of thing, but that those were hard to come by.
I don't recall saying quite that. TA would normally be done by acid/base
titration using an indicator or pH meter to judge the end point. I may
have mentioned the use of enzyme kits for determining specific acids
(malic, lactic, acetic) for which measurement of the NAD/NADH shift at
360 nm requires a quantitative UV/VIS lab spectrophotometer. They are
standard biochemistry lab equipment.
> a new, cheap ($40), DIY desktop spectrometer from Public Labs:
>
> http://publiclab.org/wiki/dsk
This seems to be a qualitative 'spectrometer' working in the visible
range only. It wouldn't be suitable for monitoring enzyme assays.
>
> There looks like there's a great deal of work on using near-infrared
> spectrometers like this for testing wine
> (http://www.thermo.com/eThermo/CMA/PDFs/Articles/articlesFile_24959.pdf,
> http://publiclab.org/notes/warren/1-19-2012/wine-spectroscopy-adam-hasler)=
> but I'm not finding anything online about how to interpret the readings
> from one of these for testing cider.
FT-IR and FT-NIR spectrometers are widely used for process and QC
monitoring in the food industry nowadays. They work in a totally
different part of the electromagnetic spectrum (infrared) than UV/VIS.
(The FT part stands for 'Fourier Transform' which is the mathematical
algorithm that is needed to allow system noise to be filtered out and
hence useful data obtained over many multiple scans).
The NIR absorption bands are complex and so these instruments are
typically used in a 'black box' mode where the levels of analytes of
interest can be correlated with some part of the spectrum or other
without knowing exactly why. The trick is to find some place that is
unique and not interfered with by other analytes - not always easy. You
have to pre-calibrate the equipment on samples of known content of eg
alcohol, sugar, protein, fat or what have you, and the calibration will
depend on the matrix. That calibration data is obtained by conventional
analysis. If the matrix changes, you need to re-calibrate. Hence cider
and wine may give similar but not identical responses. Not cheap and not
for the amateur. I think the larger UK cider makers may use them for QC
alcohol monitoring at least, but they may be doing hundreds of
measurements per day.
Chapter 4 in a book like this may help you
www.google.co.uk/search?tbo=p&tbm=bks&q=isbn:0470388285
If your University has a Food Science department, their library should
have some suitable textbooks on their shelves.
Andrew Lea
nr Oxford, UK
www.cider.org.uk
------------------------------
Subject: Variable capacity tanks
From: WhetstoneCiderWorks <whetstoneciderworks@gmail.com>
Date: Wed, 1 Jan 2014 10:09:28 -0500
We are considering the purchase of some variable capacity stainless
steel tanks, and I am curious as to the experiences that other
cidermakers have had using these tanks for storage.
We would like to be able to store cider for approximately 6 months in a
tank that we can also use as a blending tank prior to bottling and for
fermentations as well. My plan is to rig up a low pressure bleeder
valve
(http://morewinepro.com/products/inert-gas-system-variable-volume-tanks.html)
to the tanks to reduce oxygen getting pulled through the airlock,
since our cellar temperature fluctuates somewhat.
If anyone uses these tanks for "long term" storage like this we would
love to hear of your experiences, both good and bad.
Jason and Lauren MacArthur
Whetstone CiderWorks
PO Box 512
1073 MacArthur Road
Marlboro, VT 05344
802 254 5306
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Subject: Addendum: Inexpensive spectrophotometry for cider testing
From: Andrew Lea <andrew@harphill.co.uk>
Date: Wed, 01 Jan 2014 19:09:45 +0000
For interest, here is a link to the UK brochure (2.4MB download) for the
FTIR wine analysers from Foss (which I think also include a visible
spectrophotometer thrown in so you can do colour measurement in red
wines).
http://www.foss.dk/-/media/Files/Documents/IndustrySolution/BrochuresandDatashee
t/Winesegment/Wine_Segment_Brochure_GB_web%20pdf.ashx
There is more on their website here
http://www.foss.dk/industry-solution/wine/products
Doubtless these units would have to be recalibrated for cider, but if
you had the need and the budget associated with a large business it
might be worthwhile. The approximate price for the cheapest unit
(OenoFoss) is around $30K (US) I believe.
Andrew Lea
nr Oxford, UK
www.cider.org.uk
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Subject: year-end note
From: cider-request@talisman.com (Cider Digest Admin)
Date: Wed, 1 Jan 2014 13:12:54 -0700 (MST)
It may be of interest that the Cider Digest circulation increased about 10%
in 2013. In fact, growth has run around 10% per year for at least the past
five years. We currently have 1230 subscribers.
Really it's just more data confirming the increase in interest in cider.
- ---
Cider Digest cider-request@talisman.com
Dick Dunn, Digest Janitor Boulder County, Colorado USA
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End of Cider Digest #1837
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