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Cider Digest #1592
Subject: Cider Digest #1592, 4 November 2010
From: cider-request@talisman.com
Cider Digest #1592 4 November 2010
Cider and Perry Discussion Forum
Contents:
Re: Cider Digest #1590, 27 October 2010 (lotic@juno.com)
Re: pressing, Cider Digest #1591 (Bill)
Cultivar questions (John Mott)
golden russets (John Mott)
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Subject: Re: Cider Digest #1590, 27 October 2010
From: lotic@juno.com
Date: Sat, 30 Oct 2010 21:46:45 -0400
Scott Heath wrote:
"So how is that OESCO grinder working for you? I'm considering
getting one and haven't heard from anyone yet about how it rates.
I've used a couple of hammermills and those were great. Does it
compare?
Scott"
Mr. Heath,
Unfortunately, I went straight from a Jaffrey grinder to the
OESCO grinder. I was looking for a press in 2005-2006, and came across a
"full kit" in Ohio. In this kit was the grinder with custom stand,
hopper, and Jabsco pommace pump. I have been very satisfied with the
entire unit, but I have never used a hammer mill. So, I don't have much
of a reference. OESCO is about a 1/2 hour from me. It was a bit humorous
to drive all the way to Ohio to retrieve a grinder made so close by, but
good to know that parts were readily available. The head has a series of
curved plates that are spring loaded and adjustable (adjustable for apple
variety, age of apple, press type, etc.). The curved plates force the
inserted apple against an eight-inch wide (and eight-inch diameter)
rotating wheel. The wheel resembles that of a large dado head on a table
saw. The teeth are ~1/8-inch deep. It is powered by a 3-HP motor (belt
drive). came to me with a 3-phase motor, but I have rural power. So, I
switched to a single-phase motor. The thing is LOUD! It sounds a lot like
a wood chipper, and it is built as sturdy as one (Yes, it will be in
"FARGO II"). OESCO now has a different head and grinder system
(Sani-Feed). It looks sweet! All SS. Low maintenance. Easy cleaning.
Included conveyor. I don't know if there have been any significant
changes to the head. It Wish I knew more.
BTW: OESCO will be displaying their wares during Cider Days, but
I'm not sure where they will set up (check the website).
Peter Mitchell
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Subject: Re: pressing, Cider Digest #1591
From: Bill <squeeze@mars.ark.com>
Date: Sun, 31 Oct 2010 10:49:41 -0700
Andrew, I would be VERY suprised if the press structure you have shown
on your site with C channel legs could withstand anywhere near 5400psig,
or if the ram seals could [most rams are rated to 3000psig], so
obviously that force isn't being transmitted. You cite your AgCan design
press: "with an 8 ton manual jack and a 16 inch square bed which gives
about 70 psi by calculation". The "by calculation" is where the problem
lies, that 8 ton rated jack applies 8 tons at *maximum force* [not
likely achieved] to the piston in it and the small tip of the ram, not
to the press bed. My press has 4" x 12" I beam legs of 3/16 steel, and
originally they would bow with application of 2000psig to the paired 5"
rams [80,000#], so I reinforced the legs with a web of 1/2" x 3" bar
welded into the center of the leg webs, which still didn't entirely stop
all flexing at pressure beyond 2000psig. I'm not a hydraulic expert or
even an engineer, but allow some rambling from a good mechanic and an
exceptionally efficient [from reports on the list!] juice extractor in
the real world, that may help folks with this aspect of their endevors.
Physics experts are welcome to correct my real world experience.
Terry uses the same fluid dynamics formula: force per unit area,
expressed in psi for hydraulics, psi=force/area. I think this needs
consideration of just where it applies and the intervening mechanical
interface.
If you push on an object with your fingertip with a force of 2 pounds,
and the fingertip area is 1 square inch, then the pressure you are
exerting is 2#/1sq.in. = 2 pounds per square inch. OTOH, when you push
with that finger, the flesh compresses, among other things, so the force
exerted [2lbs] isn't really going to translate to 2 psi at the other
side - if a person of 200 lbs has 2 feet roughly 4"x10" [just sayin],
then the pressure exerted would be 200/80 or 10psi - OK, I was a little
off, but jumping up and down would add gravity/velocity/inertia!!
With the hydraulic press, the pressure is being applied to the rams in a
closed system, force being equal at any enclosed point. If you push a 5"
piston with 2000psi, the pressure exerted is [~area of cyl=]20"x2000# =
40,000lbs = 20 tons ["short" tons to me; 17.8 "long" tons to Andrew, or
18.1 metric tonnes], 2 cylinders total = 80,000lbs or 40 short tons.
Then we need to transfer that force from the cylinder pistons to the
pulp stack.
If the cylinders are rigidly fixed to a solid 20" sq surface [see pic
here: <http://mars.ark.com/~squeeze/pressing/1pressload.jpg> ], the
pressure appears to me to be 40 tons applied to the whole 20 sq inch
press plate - as above, the force of your fingertip becomes 80,000lbs
applied to an area of 20 individual square inches, so 80,000/20 = 4000#
*per sq inch* force exerted on the stack, a bit different than the 70 or
100 or 224psi cited "by calculation" - and seems to coincide with the
2000psi applied to 2 rams! The total square inches of the press plate
transfer system pressure on the stack. I can state with confidence that
my hydraulics can transfer a much higher portion of the applied pressure
to the stack than a similarly rated manual jack, especially with a wood
press structure.
The manual jacks that folks use exert the rated weight/psi on the area
of the cylinder in them [usually about an inch], not on the press stack,
and there's a lot of compressible/flexible materials between the small
tip of that jack and the pulp, not to mention the length of the lever
used to run the jack and the strength of the operator. Does anyone ever
pump the jack to it's maximum rated pressure? What amount of that point
pressure is actually transmitted to the press plate, let alone the
[usually light wood] racks and finally the pulp? Do any of these presses
apply enough pressure to embed coarse pulp in the weave of the cloth?
Mine does - in fact with a poorly made stack of overripe fruit I have
broken good 1/2" HD plastic racks and burst cloths [I don't always get
it right!].
I think there's a confusion of dead weight[mass] with
mechanical/hydraulic pressure, and a mixing of force and pressure, and
an assumption that the hydraulic pressure is acting on the press plate
directly, when it's actually operating on the cylinder piston, the force
from that point on being the same regardless of area if there's no
mechanical inefficiencies .... my perception is still that with
sufficiently rigid/solid mechanical transmission, the entire hydraulic
pressure is being applied and that folks are carrying fluid dynamics
principles forward improperly, so misunderstanding just how much
pressure is being delivered.
Related to this, like Andrews use of long tons while the Americans here
are thinking in short tons, is the use of terms on the list in
discussing quantities and yields. I've come to much prefer pounds [or
kilos] and litres [liters] rather than bushels and gallons and
percentages - how do I know if you mean a 3.8 litre US gallon or a 4.5
litre Imperial gallon or even the 4 litre "metric gallon" that became
common here when Canada adopted metric? If you state you get 3 gallons
per bushel is that 11.4 litres or 13.5 litres? Was the bushel 48# [US
legal definition for apple bushels] or is it 45# [common use] or
something else altogether, like simply a wooden basket of unknown
volume? In Canada an apple bin is considered 18 bushels, but is also
thought to be 850# [47.2#/bushel??], while filled level it's about
1000#. Which of those variable measures give your percentage yield? I
frequently use bannana boxes filled level as a "bushel", and have
weighed that to be 50#. My yields, as previously stated, are pretty
consistently 1 litre from 3#, and I can do better with crisp fresh
fruit, especially hard pears, and a few more minutes drip time. If a
litre weighs 2.2# [water] that's about 74%, but we know juice weighs
more than water. If I end up with 3/4# of pomace for each litre then
it's 90%, and I've actually measured/weighed these things with an eye
for turning the pomace into a saleable product, so I'd have to say my
yields are as much as 90%. Hope that's helpful for y'alls off season
musings!
Bill <http://mars.ark.com/~squeeze/>
------------------------------
Subject: Cultivar questions
From: John Mott <john@johnmott.com>
Date: Wed, 3 Nov 2010 17:41:57 -0400
Thanks to Claude and Bill for your helpful responses.
/John Mott
Kimberely, ON
------------------------------
Subject: golden russets
From: John Mott <john@johnmott.com>
Date: Wed, 3 Nov 2010 17:45:59 -0400
I pressed some golden russets this past weekend and measured these results:
S.G. - 1.059
PH - 3.8
T.A. - 4.6 g/L as malic
Just wondering how these numbers compare with others who have measured
golden russets
/John Mott
Kimberley, Ontario
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End of Cider Digest #1592
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