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Cider Digest #1564
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Subject: Cider Digest #1564, 10 May 2010
From: cider-request@talisman.com
Cider Digest #1564 10 May 2010
Cider and Perry Discussion Forum
Contents:
why apples float (Bill)
Flotation in keeving ("Gary Awdey")
Why do apples float? (Andrew Lea)
Terry Maloney memorial (Andrew Lea)
Redfield (remembering Terry) (Dick Dunn)
NOTE: Digest appears whenever there is enough material to send one.
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Digest Janitor: Dick Dunn
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Subject: why apples float
From: Bill <squeeze@mars.ark.com>
Date: Wed, 05 May 2010 23:25:57 -0700
Because 20-25% of an apples volume is air. ;)
Bill <http://mars.ark.com/~squeeze/>
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Subject: Flotation in keeving
From: "Gary Awdey" <gawdey@comcast.net>
Date: Thu, 6 May 2010 07:13:06 -0500
In CD# 1563 Warwick wrote:
> Winemakers sometimes do something called flotation, where gas is
> dissolved into the fresh juice under pressure and then released which
> creates a foam (sort of same effect as a widget in a Guiness can), and
> they can then rack out from under the juice. This took me to the
> thought that maybe it would be a more reliable way to get a consistent
> keeve - anyone tried it?
Flotation is a technique that has been used in French cider factories for a
number of years. The must is treated with the enzyme pectin methyl esterase
(PME), which as Andrew Lea has noted on a number of occasions is not the
same thing as the pectic enzyme you find in most homebrew and winemaking
supply shops (pectic enzyme is a cocktail blend of a number of different
enzymes, each serving a different specific purpose). The PME treatment may
begin as early as the maceration process, with the enzyme added to the
milled fruit in order to maximize pectin loading of the must. The must is
then treated with a calcium salt (usually calcium chloride). At the
appropriate time it is pumped through a flotation chamber where nitrogen gas
lifts the precipitating calcium pectate and suspended solids. The equipment
used is somewhat specialized and from what I gather the process occurs with
the must under a pressure of about 5 bars (roughly 70 PSI). Perhaps this
helps to control the bubble size and therefore the turbulence. An effort to
try this at one atmosphere with the best gas diffusion stone I could find
resulted in such high shear forces from the bubbles that the calcium pectate
gel was immediately broken apart and stirred back into fine suspension, a
sudden and dramatic failure of the keeving process. My motivation to
experiment further with the stone under cyclic pressure was not high because
good results were being obtained with the more traditional batch keeving
process and with other tricks discovered by trial and error (such as
carefully timed introduction of active yeast so it becomes suspended in the
viscous must rather than settle to the bottom of the keeving vessel).
However larger commercial producers work under time and space constraints
that make the less traditional flotation process more attractive and worth
the trouble.
Experiments in my cellar have shown that the PME and calcium chloride doses
employed by French cider factories with flotation equipment produce a very
high pectin load that frequently forms a solid block of gel if there is not
sufficient yeast activity to produce gas to lift the pectin and compact it.
When clarification of such musts is less than complete due to slight
agitation there is still an appreciable reduction of suspended solids and
subsequent reduction of fermentation rate (and appreciable residual sugar
remaining at the end of fermentation for most batches that are subsequently
racked). Without PME-aided maceration the pectin load tends to be much
lower and the pectin gel structure tends to be much more fragile and
vulnerable to breaking apart easily. One additional thing that French
factories may have in their arsenal of tricks that most of us won't have is
the ability to centrifuge, a prefiltration step that helps remove additional
suspended solids that tend to overload filters quickly. French and English
research dating back to the early 20th century shows that use of a
centrifuge provides many of the same advantages of keeving if it is done at
the right time and with a gas blanket t o avoid unintentional oxygenation of
the must.
Interestingly, the available information for use of flotation for wine
suggests that it works better when there is lower viscosity (i.e. less
pectin) and use of pectic enzyme is recommended. It also suggests that
results are improved when gelatin or fining agents such as bentonite are
added (thought he addition of gelatin would seem to work against reduction
of viscosity). These are not things that I would consider adding to a more
traditionally macerated and keeved cider because they are unnecessary and
each has its own drawbacks. If you want to keeve on a limited scale and
don't have a disproportionately huge equipment budget then you should be
prepared to deal with a process that often can be very slow.
Gary Awdey
Valparaiso, Indiana
------------------------------
Subject: Why do apples float?
From: Andrew Lea <andrew@HarpHill.co.uk>
Date: Thu, 06 May 2010 19:30:15 +0100
Warwick Billings asked:
> Why do apples float?
Apples float in water, whereas pears and grapes don't, because apples
have larger air-filled inter-cellular spaces, enough to give the overall
fruit a density less than 1. It's that simple. See for instance
http://jxb.oxfordjournals.org/cgi/content/full/55/399/1061 and
http://www.plantphysiol.org/cgi/content/full/147/2/518
> Winemakers sometimes do something called flotation, where gas is
> dissolved into the fresh juice under pressure and then released which
> creates a foam (sort of same effect as a widget in a Guiness can), and
> they can then rack out from under the juice. This took me to the
> thought that maybe it would be a more reliable way to get a consistent
> keeve - anyone tried it?
Never tried it myself, but I'm told that nitrogen flotation to aid
keeving is common practice in the large scale French cider industry. It
enables a keeve to be obtained within hours rather than the days you
have to wait if you use natural CO2-generating processes from yeast.
Andrew Lea
nr Oxford, UK
www.cider.org.uk
------------------------------
Subject: Terry Maloney memorial
From: Andrew Lea <andrew@HarpHill.co.uk>
Date: Thu, 06 May 2010 19:34:58 +0100
Ben Watson wrote:
> A memorial for Terry Maloney of West County Cider, who died suddenly in a
> tragic accident at the end of January, will be held on May 22, 2010 starting
> at 11 am. The location is the East Colrain Chapel, at 341 West Leyden Road,
> Colrain, MA 01340 (for anyone interested who's interested in attending and
> needs to get Internet directions).
Ben,
For those of us who cannot possibly be there in person but would like to
be there in spirit, will there be any chance of obtaining some sort of
copy of any written / spoken tributes / eulogies? A PDF in return
perhaps for a donation to a chosen charity?
Andrew
------------------------------
Subject: Redfield (remembering Terry)
From: Dick Dunn <rcd@talisman.com>
Date: Thu, 6 May 2010 16:58:22 -0600
speaking of remembering Terry Maloney...
West County's "Redfield" cider has always been a favorite of ours,
particularly of my wife (Diane). A few years ago I had asked Terry
for some scionwood of Redfield, which he kindly sent. All of the
Redfield grafts took, so now I have a little section of Redfield in
my orchard. This year it feels like a memorial...I think about Terry
every time I'm out there. I hope I'll eventually be able to incorporate
the Redfield fruit into a cider as Terry did...it's a challenge, being
a severe bittersharp.
The trees are robust and precocious. I've been trying a lot of apple
varieties here in our erratic climate, and many of them behave as if
they only sorta put up with the weather. But the Redfield grows as
if it -likes- it here...certainly not finicky or dainty.
The Redfield is distinctive--everything about it is red! So they always
catch my eye, particularly now at blossom...they're one of the reddest
blooms I've ever seen on a non-crab type. The bark is maroon; the
leaves are reddish-bronze. The fruit is a darker and more uniform
color than a Kingston Black, and the flesh is streaked red as well.
To my surprise when I was grafting, even the wood is flecked with red!
- --
Dick Dunn rcd@talisman.com Hygiene, Colorado USA
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End of Cider Digest #1564
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