[Cider Workshop] corny kegs for fermentation and storage

[Nat West]

I have been doing primary in plastic buckets and glass carboys, but after speaking with some homebrew friends, I am wondering if I should transition to using corny kegs after primary subsides, for the first racking and/or second "long term storage racking". The benefits of corny kegs are that they are far more durable, stackable, abusable, easier to clean than carboys, and "finished" cider can be left in them for a long period. They are available secondhand with some regularity.

Is there anything wrong with the following procedure?

1. Primary ferment in plastic, 5-gal buckets or big 30-50 gallon barrels.

2. After primary subsides, rack into corny kegs, purge with CO2. Optionally, rack into glass carboys, seal with airlock.

3. Months later, "bottle" into cornies via CO2 purge, sealing, no sugar for priming.

4. Months later, tap corny, dispense with CO2, store in keg-fridge, and take a month or more to drink one keg.

I should mention I am speaking entirely of dry still cider.

How long will cider keep in step 3? How long will cider keep in step 4? My homebrew friends believe it will last a good long time and that beer is stored in kegs for a year or more. They also believe that there is less leakage from a keg's seals than from a well-fitted airlock in the long term. I will continue to bottle some cider into champers but since 75% of my cider is consumed on-site, I could save myself an immense amount of work if the above steps could work.

I'm not sure why I'm just considering this now. Am I missing something?

Thanks for the advice,

-Nat West, Portland Oregon

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[BristolCider]

I use cornelius kegs quite a bit (I am in the UK but it's still
possible to buy the 19litre kegs for £25 or so, much cheaper in the
states I understand) and as long as a fairly bright product is going
into the keg there will be little or no sediment drawn off via the dip
tube.

The kegs need a blast of CO2 to seal them - say 10 - 20 psi - and some
of the gas will go into solution carbonating the cider, sometimes
enough CO2 that the seal is lost (the seal relies on internal
pressure). The cider will inevitably take on a sparkle and you may
well have to keep checking the seal and occasionally topping up the
CO2 to make the seal. Other than venting the gas over a week or so
near the time you want to serve the cider it's never going to be a
still product.

If you think of the Corny keg as a big bottle then the cider inside
will most likely keep as long as it would in a bottle, I've got
elderflower wine from 18 months ago in one and it's still perfect.

[Andrew Lea]

On 18/05/2010 20:22, BristolCider wrote:
>
> If you think of the Corny keg as a big bottle then the cider inside
> will most likely keep as long as it would in a bottle, I've got
> elderflower wine from 18 months ago in one and it's still perfect.
>

I too have used them as big airtight bottles for storage (I acquired
them when a much lamented Bristol area(l) research station closed down,
where they had been used for experimental fermentation since the 60's),
though I have never used them for dispense as such. I have also 'bottle
conditioned' in them quite successfully and then after chilling
transferred to glass bottles or plastic kegs for final dispense eg for a
party. The ones I used have a blow off-valve incorporated (set at 5
psi?) so they cannot build up excess pressure. I have never applied
exogenous CO2 - it's all been generated by deliberate secondary
fermentation after sugar addition. I have had cider stored in them a
year or more.

My only comment is that the inside steel surface does become noticeably
discoloured on long storage of cider. However, I was unaware of any
oxidised or metallic taints. Nat's plan seems good to me and I only
wonder that more people don't do it.

Andrew

--
Wittenham Hill Cider Pages
www.cider.org.uk

[Dick Dunn]

On Tue, May 18, 2010 at 08:38:32PM +0100, Andrew Lea wrote:
...
> ... The ones I used have a blow off-valve incorporated (set at 5
> psi?) so they cannot build up excess pressure...

Andrew - The relief valve is standard, but are you sure it was so low?
I've never tried to "push it" with mine but I'm sure they'll hold 20 psi.
The kegs are rated at over 100 psi, and since they're designed to hold
soda--keeping in mind the American penchant for a wretched excess of
carbonation--I would guess you could put 50 psi on.

> My only comment is that the inside steel surface does become noticeably
> discoloured on long storage of cider. However, I was unaware of any

> oxidised or metallic taints...

Is that discoloration from tannin perhaps? I notice that on various metal
parts in my operation, even short-term contact as in pressing, and even on
polished stainless.

Also, someone else (not Andrew) had mentioned that the kegs rely on
internal pressure for sealing. This is not true of the ones I've seen,
namely current/recent Cornelius (actual brand) ball-lock types:
- The lid seal is an O-ring pulled tight by the bail on the lid.
- The pressure relief in the lid has a fairly strong spring, plus
outside pressure should drive it tighter.
- The poppets on liquid and gas fittings also have strong springs for
their size.

If you've just obtained a used keg and aren't sure how well it seals,
put some hot water in and slosh it around to heat the air, then quickly
seal it up. Come back the next day and release one of the seals. It
should draw air into the keg when you do that (meaning it shouldn't have
leaked in overnight).

However, on the same note, if you've obtained a used keg and aren't sure
of the provenance, just replace the poppets, O-rings, and lid seal anyway.
Not only will this avoid sealing worries; it will avoid cider tasting
like root beer.
--
Dick Dunn rc...@talisman.com Hygiene, Colorado USA

[Nat West]

Thanks to Dick, Andrew and Mr. Bristol, this is great news for me. I'll be on the hunt for corny kegs in the next few weeks to "bottle" my 2009 cider.

Dick, my homebrew friends recommend always getting new o-rings for any kegs, as a standard operating procedure. 

Andrew & Dick, if the kegs don't rely on internal pressure to seal (as Mr. Bristol says), would the pressure relief valve serve as something of an airlock? If I add priming sugar, or get some secondary fermentation creating CO2, I suppose any excess gas would bleed off through the valve.

Also, regarding sediment at the bottom, I have heard that it's only about the first pint sucked up when the keg is tapped that is undrinkable. I hope that's so for cider.

-Nat West, Portland Oregon

[Andrew Lea]

[I'm sending this on Dick's behalf - Andrew]

I don't know why my last posting on corny kegs appeared six times.
The message was only sent once, as I've checked here by logs and
Message-ID. If you're curious about what I wrote, might be best
to contact me off-list. I won't try posting again for a day or
two.

Dick Dunn r...@talisman.com Hygiene, Colorado USA

[Aric Hagberg]

On Tue, May 18, 2010 at 8:02 PM, Nat West <natj...@gmail.com> wrote:
> Thanks to Dick, Andrew and Mr. Bristol, this is great news for me. I'll be
> on the hunt for corny kegs in the next few weeks to "bottle" my 2009 cider.
> Dick, my homebrew friends recommend always getting new o-rings for any kegs,
> as a standard operating procedure.
> Andrew & Dick, if the kegs don't rely on internal pressure to seal (as Mr.
> Bristol says), would the pressure relief valve serve as something of an
> airlock? If I add priming sugar, or get some secondary fermentation creating
> CO2, I suppose any excess gas would bleed off through the valve.
> Also, regarding sediment at the bottom, I have heard that it's only about
> the first pint sucked up when the keg is tapped that is undrinkable. I hope
> that's so for cider.

I've been using Corny kegs for the past three years of cider making
with good success.

I originally started using them as secondaries like Nat is proposing.
But two years ago, after I dropped and shattered a full 5 gallon carboy,
I got motivated to see if I could use them as primary fermentation
containers too.

I found a place that was selling lids without the usual airlock in the
center - just an empty hole where I assume the old broken airlock was.
One of my drilled stoppers fits perfectly into the hole and the
airlock
fits into the drilled hole. That's it.

When the fermentation is done you can either gravity rack into a
secondary corny or using a little extra plumbing you can do it under
low pressure. In that case you have an oxygen-free racking system if
you first purge the secondary corny using CO2. Since the secondary
is under a little pressure when you start you have already guaranteed
that it seals correctly.

I pump the cider directly out of the secondary to drink. The first
pint will have some sediment but after that it's all good. Andrew is
correct that you will get a little sparkle whether you want it or
not. But if you keep the storage pressure low (bleed gas from the
relief
valve on top) it is very little.

I haven't experienced much difficulty making good seals with the keg
lids. I use new seals and a food-safe lubricant that I think helps that.
Also so far I've seen no discoloring of the stainless steel but I haven't
had much high tannin fruit to test the theory that it might be the cause.

Aric Hagberg, Santa Fe, New Mexico

[BristolCider]

There are a number of variations on the "corny keg" design, my own are
of at least three different types, however the standard pressure
release valve is set (and fixed) at around 100psi - these are high
pressure vessels. Equally of all the variants I have (mostly
spartenberg challenger and sparten by cornelius), none achieve an
airtight seal without additional internal pressure and I don't know
anyone else who can achieve a seal without internal pressure either.

Possibly we are talking about different types of keg here?

[Andrew Lea]

On 19/05/2010 18:13, BristolCider wrote:
> There are a number of variations on the "corny keg" design, my own are
> of at least three different types, however the standard pressure
> release valve is set (and fixed) at around 100psi - these are high
> pressure vessels.

It was silly of me to suggest yesterday that the relief valves could
operate as low as 5 psi when you consider that their original use is to
dispense carbonated soft drinks at (I believe) around 20 psi. So
obviously the relief valve must be set higher than that. My confusion
was that I think we operated them as experimental fermenters at 5 psi
overpressure. I think that was achieved by some purpose-built restrictor
on the outlet valve - just a fancy airlock really.
In answer to Nat's question, 100 psi is far too high to function as an
airlock per se - that amount of CO2 would intoxicate the yeast and stop
it working.

> none achieve an
> airtight seal without additional internal pressure and I don't know
> anyone else who can achieve a seal without internal pressure either.

When I have used them at home to secondary ferment ciders, I have
certainly had problems with some of them (not all) failing to seal
properly even though they were firmly latched with a (greased) O-ring in
place. Looking at the design it would appear that internal pressure
should certainly seal them tighter. Or maybe my O-rings are rather tired
(probably the originals and around 40 years old!)

>
> Possibly we are talking about different types of keg here?

I inherited at least two kinds (US and German) but although they differ
in detail they seem to be fundamentally the same concept. Since I
already have them and they are underutilised, I have often wondered
about using them for dispense of a naturally conditioned cider but have
never done so, which is why I have an interest in this thread. I have
none of the inlet / outlet connectors though - presumably they can be
purchased somewhere?

Andrew

--
Wittenham Hill Cider Pages
www.cider.org.uk

[BristolCider]

The connectors are readily available (they are known as disconnects
for some reason). Beware as there are two formats - pin lock (a
bayonet style fitting) and ball lock, one was favoured by Coca Cola
and one by Pepsi Cola so I understand. The Ball lock type are much
more common than the pin lock in the UK. You need differing ones for
each format for the in and out connections - the pin lock variety has
a differing number of pins and the ball lock variety has slightly
different diameters.

Most on-line (and many real) home brew shops sell the ball lock types;
http://www.brewuk.co.uk/store/index.php/grey-disconnect.html?___store=default
Nd and http://www.brewuk.co.uk/store/index.php/black-disconnect.html?___store=default
the ball lock types are a bit harder to obtain but often pop up on
eBay.

Oh and I'm Roger (Mr Bristol sounds too grand) I read a lot here and
take it all in, don't have lots to say.

[Dick Dunn]

On sealing "Corny" kegs and pressure...
On Wed, May 19, 2010 at 10:13:31AM -0700, BristolCider wrote:
> ... Equally of all the variants I have (mostly

> spartenberg challenger and sparten by cornelius), none achieve an
> airtight seal without additional internal pressure and I don't know
> anyone else who can achieve a seal without internal pressure either.
>
> Possibly we are talking about different types of keg here?

No, we're talking about variations on the same design, and you should be
able to get the keg to seal without internal pressure. The kegs I use
are Cornelius "Super Champion"s and half-size (2.5 gal) AEBs from Italy.
I did a test on one of each of these yesterday; they held a seal for a
day, with -negative- pressure no less, meaning that the pressure in the
keg was -lower- than outside.

(I purchased the AEB's new. My Corny's are all used and suffered various
amounts of abuse in their former lives.)

First, be sure of where you're not getting a proper seal--see further
down in this note. But almost always it's the large O-ring on the lid
(the one that's about 10 cm dia and 8 mm thick) that is the source of
failure.

There are three main reasons for a Corny-style keg lid not to seal
on its own (without internal pressure). In order of likelihood:
Damaged or old O-ring.
Worn or damaged feet on the bail that pulls the lid tight.
Dented/deformed edges on the lid or the lid-opening in the keg.

The big O-ring is the most common problem. It gets stiff/brittle
with age (just like the rest of us) so that the bail on the lid can't
pull it tight all around. If the keg was kept sealed for a long time
it may have taken a "set" and won't seal right once the ring has been
removed/replaced in a different position on the lid. Or it may just be
too stiff for the bail to squeeze it into a seal. The obvious solution
here is just to replace the ring. Also, there are replacement rings
which are slightly larger and softer--these can make it easier to
get a better seal if there are other difficulties. In the US, you
can get them from William's Brewing, but they don't ship overseas,
so somebody else will have to help out on that. Still, a standard
ring in good condition -will- seal without pressure.

Next possibility is the feet on the bail--these bear against the top
of the keg when you pull the lid tight. If they wear or have gotten
munged, the bail won't exert enough pressure to pull the seal tight.
Replacements are available.

Damaged edges on the lid or opening are least common but hardest to
deal with. A single small bit of damage might yield to careful use
of force. The oversize/soft ring mentioned above can help. You can
get a complete replacement lid, but a new lid costs almost as much as
a used keg.


OK, now, to be sure where the keg is leaking: This takes a test with
back-pressure. Get the keg ready to seal. Put a few litres of HOT water
in the keg. Don't fill it! You want just enough to heat it up. Put
the lid on and pull it tight. Shake the keg around to slosh the water.
Put the keg down and vent it through the pressure-relief valve (pull
up). Maybe do this a second time. What you're doing is heating the
air inside the keg so it wants to expand, then venting it to outside
pressure. Then as the keg cools the air pressure inside drops. As it
cools, listen for noises around the post poppets, the lid seal, and
the pressure relief. A drop of water on each poppet will tell whether
the leak is there, if the water disappears. Water around the seal may
cause it to whistle or gurgle very faintly where the leak is.

--
Dick Dunn rc...@talisman.com Hygiene, Colorado USA

[Nat West]

Dick, could you add the hot water, swish it around, and drop it in a bathtub or a water-filled trash can to look for air leaking/bubbles?

NAT

On Thu, May 20, 2010 at 8:07 PM, Dick Dunn <rc...@talisman.com> wrote:

OK, now, to be sure where the keg is leaking:  This takes a test with
back-pressure.  Get the keg ready to seal.  Put a few litres of HOT water
in the keg.  Don't fill it!  You want just enough to heat it up.  Put
the lid on and pull it tight.  Shake the keg around to slosh the water.
Put the keg down and vent it through the pressure-relief valve (pull
up).  Maybe do this a second time.  What you're doing is heating the
air inside the keg so it wants to expand, then venting it to outside
pressure.  Then as the keg cools the air pressure inside drops.  As it
cools, listen for noises around the post poppets, the lid seal, and
the pressure relief.  A drop of water on each poppet will tell whether
the leak is there, if the water disappears.  Water around the seal may
cause it to whistle or gurgle very faintly where the leak is.

--

[Dick Dunn]

On Thu, May 20, 2010 at 08:33:25PM -0700, Nat West wrote:
> Dick, could you add the hot water, swish it around, and drop it in a bathtub
> or a water-filled trash can to look for air leaking/bubbles?

No, because you've got negative pressure. Any leakage goes -into- the keg,
not out of it. What we're trying to do here is establish the ability to
close the keg -without- pressure pushing the lid seal and post poppets
closed, which is why the negative-pressure test is helpful.

Hmmm...I suppose you could use food coloring and water to verify where the
leak is? Put a drop of blue on gas-in, red on liquid-out, green around
the seal, then after the pressure drops, rinse the outside and see what's
gotten inside? I dunno...just thinking like an engineer who's had one
too many pints.

> NAT
>
> On Thu, May 20, 2010 at 8:07 PM, Dick Dunn <rc...@talisman.com> wrote:
>
> > OK, now, to be sure where the keg is leaking: This takes a test with
> > back-pressure. Get the keg ready to seal. Put a few litres of HOT water
> > in the keg. Don't fill it! You want just enough to heat it up. Put
> > the lid on and pull it tight. Shake the keg around to slosh the water.
> > Put the keg down and vent it through the pressure-relief valve (pull
> > up). Maybe do this a second time. What you're doing is heating the
> > air inside the keg so it wants to expand, then venting it to outside
> > pressure. Then as the keg cools the air pressure inside drops. As it
> > cools, listen for noises around the post poppets, the lid seal, and
> > the pressure relief. A drop of water on each poppet will tell whether
> > the leak is there, if the water disappears. Water around the seal may
> > cause it to whistle or gurgle very faintly where the leak is.
> >
> >

--

Dick Dunn rc...@talisman.com Hygiene, Colorado USA