Some of you
may remember a discussion we had last autumn about keeving. I like to
experiment with the noble art at the back end of the pressing season. Every
year I seem to learn something of value to add to my knowledge of the subject.
Last year something happened that I had not experienced before. It was what
I've come to consider as partial keeving.
Usually I
find that keeving works well or not at all, depending on whether pectin
defecation takes place before the onset of fermentation. This in turn owes much
to the ambient temperature, which is why I do not keeve until late November.
Last year I keeved 5 varieties with results as follows:
Porter's
Perfection good
keeve SG held at 1020
Kingston
Black good
keeve SG held at 1025
Dabinett fermented
too soon, went fully dry
Yarlington
Mill partial
keeve SG seemed stable at
1012
Ashmead's
Kernel partial
keeve SG seemed stable at
1010
The last two
varieties both managed to produce a thin chapeau brun
of about 10 mm thickness, compared to the 30 mm or more produced by PP and KB.
Nevertheless I was still able to rack nice clear juice from below both of the
thin caps. I considered that as this had taken place before fermentation
started, a measure of keeving had occurred.
I like to
soften the acidity of Porters by blending. The year before I
found that a blend of Porters and Dabinett was particularly pleasing. Both
had keeved well and the residual sweetness continued to be stable in their
blend. As Dabinett did not keeve last year I decided to try the same thing by
blending Yarlington and Porters. Their combination yielded a SG of 1015. My
question for the Forum was what would be the end result? Would the SG hold at
around 1015, or would the remaining nutrient in the poorly
keeved Yarlington allow further fermentation to take the blend to fully dry?
Nobody could give a definite answer. The only thing to do was to wait and see!
The last few
weeks have seen me frantically bottling everything that I did not manage to
bottle earlier in the year. I'm desperate to clear the deck for action! Nehous
are invading next week, and will be closely followed by the usual cohort of Tom
Putts and other earlies. However, the late bottling
has given me another chance to look at those final SGs
and so provide the answer to the question of mixing keeved ciders. The answer
my friends, is to 'beware of the partial keeve'!
The Porters/Yarlington
blend has been dragged down to fully dry by the
Yarlington. Both Yarlington and Ashmeads as single varieties are also now fully
dry. They are still very good as dry ciders, having benefited from
clarification, though sadly lacking any of the keeved apple sweetness. On the
plus side, both the Kingston Black and Porters, as individual ciders, have held
the keeve, retaining some of their yummy natural sweetness.
Rose
(Brought
in from the Cider Workshop)
David
Pickering wrote:
Rose mentioned the doubt which is now in her mind about the
hopper.
“a better flow of
pomace is achieved if the hopper only has two opposite sides sloping towards
the outlet ( like a piece cut from a cheese ). .....my hopper design, with its
4 sloping sides, was likely to jam”
It's far from a complete solution but might it be possible to perhaps subdivide
the hopper with a vertical baffle? In this way you may be able to reduce the
interaction of the pomace sliding from four different directions such that
there are two streams each coming from two directions eg
by a diagonal division or by turning the square(?) hopper into two rectangles.
The newly created problem is however that the outlet is now halved in area and
therefore would presumably be more prone to bridging. Has anybody studied Fluid
Mechanics 101 or Semi Fluid Mechanics 101.5?
Alternately, is it a proposition to pump a proportion of the
expressed juice back up to the hopper in order to improve the flow
characteristics of the pomace? As something approaching slurry - wetter
and heavier - it would surely flow better.
David, thank you for your thoughts
about the problem that is now foremost in my mind.
I have considered the idea of a baffle, but have almost
ruled it out due to the problem of filling both halves of the hopper equally. I
want to be able just to dangle the pomace pipe over the top of the hopper so
that it fills the thing in the simplest way. Though perhaps a
little baffle across the lower sloping part of the hopper, but of limited
height, would be useful. It could be worth a try. I also like your
suggestion of using some juice feedback. It is a method I sometimes employ with
the Mono pump. Some apple varieties have much less free juice after milling
than others and it helps to be able to add a little of the previously pressed
juice back to the pump to 'oil the works'.
There is a secret weapon available here now that I may fall
back on, if the going gets sticky! This is the stainless paddle stirrer
complete with motor/gearbox, that I have removed from
the milk cooler tank that Barry kindly acquired for me this year. I could twist
the paddle blades, aircraft propeller like, and mount it above the hopper. The
paddles would then slowly rotate within the pomace, continually driving it
downwards towards the hopper exit.
I hope that actually all will be well without such
complications, since I have a good leak-proof valve that I intend to fit this
weekend. The juice should therefore remain in the pomace and keep it sloppy
enough to fall out of the hopper. Like all of these stabs in the dark realms of
cider process engineering, it is an act of faith that could end up as a waste
of time and money! (I've been there before with that ridiculous elevator,
towering over the barn roof!)
Nothing ventured, nothing gained! As they say.
Rose.