Cider by Rosie

I’ve been mulling over the pearls of wisdom from David and Gary with
regard to the errors in SG measurement due to temperature variation
and the phenomenom of stratification. When making dry cider these
effects are of no great concern. Apart from the all important
measurement of SG prior to fermentation, thereafter the hydrometer
really only serves as an indicator to confirm that fermentation is
complete. This is quite a different matter when it comes to keeved
cider. The SG reading and its rate of fall, is crucial at bottling
time. One needs to be able to determine that the yeast is becoming
starved and that the SG is ‘bottoming out’. Only then can bottling be
safely carried out. At SGs above 1010, one has to feel confident that
there will not be the potential for more than the small amount of
fermentation needed to produce a sparkle. I’m all the more conscious
of this now having seen the bottle figures in Andrew’s book. The most
a champagne bottle can stand is 1010, should the fermentation decide
to go to fully dry.

At this time of the year I’m watching the SGs of the keeved ciders
almost day by day, in order to establish when it will be safe to
bottle. We discussed this here last year and a useful rule of thumb
came to light. If I’ve remembered it incorrectly, please somebody put
me right, but I believe that if a one point drop of SG takes a period
of 10 days or more, it can be taken as an indication that the SG is
bottoming out and that it is safe to bottle.

The implication is that for keeving it is important to be able to read
SG to within a degree and therefore reading errors do need to be
considered. I’ve looked in vain for some figures. David please
enlighten me. Say for example the ambient temp is 10 C, how is the
hydrometer reading affected? Regarding errors due to stratification,
that is something that I never would have even thought about. Thank
you Gary, it is good to be aware of it. I will have a gentle stir
before measuring in future, if notable changes in temperature have
occurred.

Continuing the experimental 50/50 blending of the keeved Porters and
Yarlington, I’ve progressed from the demijohn and now have a 120 litre
tub of it. Like the demijohn, this is also holding at 1012. As the
two ciders were well mixed during their blending, I needn’t worry
about stratification. Since the weather has stayed the same for two
weeks, around 15 C every day, there is no difference between
hydrometer readings due to temperature. Another week of similar
readings and perhaps I will feel confident enough to bottle!

I’m looking forward to bottling because I’m dying to try out Barry’s
corker, that he has kindly lent me.

Rose.

On 19 Mar 2009, at 11:11, Gary Awdey wrote:

> On Tuesday, March 17, 2009, David Llewellyn wrote:

>> Apart from the accuracy problem of actually determining small
>> differences while reading along a scale, if the
>> temperature of the cider was much lower at the time of the first
>> reading (ie the cold weather we had weeks ago), it might have accounted for an
>> apparent small change in SG, unless you corrected the readings to 20 degrees
>> C for example. The lower the temperature of the liquid, the higher the SG
>> reading will be, so you have to correct to a standard temperature. Sorry if
>> you have already taken this into account!!
>
> Another cautionary note (with more apologies if you’ve already taken
> this into account) is the effect of stratification. In the past I’ve
> occasionally noted odd readings that go counter to what would be
> predicted by the temperature density effect David mentions. When it is warmer
> you would expect density (and gravity readings) to be lower. What I’ve
> found is that sometimes the warmer weather makes fermentation of keeved
> ciders more active with the result that it is de-stratified. Measurement after
> racking is also occasionally higher than measurement before (I generally take
> samples from near the top). Heavier cider, richer in sugar, is
> mixed up from the bottom when fermentation is more active. This phenomenon is
> mentioned in several winemaking books so evidently it is not
> particularly unusual. When an accurate gravity reading of the entire batch is
> needed (which is admittedly not very often) I make sure the cider is
> adequately mixed by stirring or sparging with carbon dioxide gas (taking care
> not to introduce oxygen at the same time). However I don’t attempt to
> destratify cider that is still sitting on top of deposits that might be
> disturbed. I usually mix blended ciders thoroughly before measuring gravity.
> Otherwise measurement tends to be skewed toward the low side (and presumably the
> opposite would be true if samples were obtained from the bottom of the
> vessel).
>
> Similarly, if two keeved ciders are mixed and fermentation is very
> slow (as one would hope it would be) then you may start with a well mixed
> blend but see measured gravity drop unexpectedly quickly as stratification
> occurs. This would seem to be more likely as a cause of possible measurement
> error if you see a notable drop in gravity without seeing a corresponding
> amount of gas escaping at the airlock.
>
> Gary Awdey
> Eden, New York

Nigel,

My Europump is yellow, though I’m not surprised by yours being blue as
the new ones in the catalogue are red. The Italians are either just
fond of colour, or perhaps the colours could relate to a number of
engineering upgrades. I think my yellow one is a MK 1 prototype! As
for the spares, I do know that Barry, being desperate to obtain a
replacement for the little spring that couples the motor to the pump,
eventually made contact with the manufacturer and found them to be
very helpful. Mind you, I think he has got a whole box full of tiny
springs now!

It is a pity that Vigo have not acquired the full range of spares to
provide a back up, in the same way that they have, for example with
their stainless 850 & 1500 mills. I don’t really want a box of glands.

Perhaps Barry will come up with the contact details.

Rose.

cider nigel wrote:

> |Hello Rose
>
> I have said blue pump, it has never siezed or cut out it was a super
> thing, however Alex cant supply impellers and so it sits on the
> shelf , if you have a source of bits I would love to know.
>
> Many thanks,
> Nigel.

Dont throw away that Europump!

Like many of us here, I’ve been using one of Vigo’s little Italian
europumps for a good few years. It is such a useful pump for all
manner of small filling jobs. Its only vice is the well known
propensity of cutting out to rest and cool down, after about 20
minutes of continuous use. I have been able to forgive this little
foible, because it is usually possible to fit in some other part of
the job, while the pump cools down.

I have noticed another problem, in that after a long period of non use
the pump can refuse to start at all. This is because the pump rotor
has stuck to the steel end plate of the plastic pump housing. It seems
to happen, no matter how well the pump was flushed out with water
before being laid up. The cure is simply to remove the three screws
holding the end plate. Take the plate off and clean it, give the rotor
a little twiddle by hand and then reassemble the plate.

I’ve had to do this this a number of times, so I was not surprised
when I got the pump out today and found that it would not start.
However on this occasion I found that the pump rotor was well and
truly stuck. The motor had seized completely. I was about to ring Vigo
for a new pump, when I thought that I might as well look inside the
pump to see if it could be fixed. This proved to be easily done, since
the two halves of the case are held together by self tapping screws. I
then found something, rarely seen these days. The little motor was
made to be serviced! Five minutes later I had the whole thing to
pieces. The armature and bearing plates were easily removed from the
motor body, just by undoing two nuts and bolts. The armature shaft was
solidly seized to the bearings, but I was able to remedy this with a
spray or two of WD40. Another 5 minutes and the Europump was back
together and working once again. It is a joy to service, not a rivet
or ‘tamperproof’ screw anywhere within its little body!

The problem had been caused by the ingress of juice via the gland on
the pump drive shaft. It really could do with a new gland, from
somewhere. In the meantime I will try and prevent a reoccurrence by
making sure never to use it with its pump end uppermost (ie above the
motor).

These little pumps defy the throw away age!

Rose.