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Oval-necked demijohn - fix/throw out ?

Posted: Wed Jul 11, 2018 10:35 am
by elfcurry
I have two demijohns* which leak around the bung. I tried different bungs, tried pushing the bung in tighter and making sure it's moist but the glugging soon comes to a stop, a sure sign it's not sealed. Can they be redeemed somehow or should they be thrown out?

If no fix is available, can they be re-used for something else, or recycled along with glass jars & bottles or put in 'other waste'.

*out of seven; it was eight until last December when my lodger knocked a gallon of blackberry wine, ready for bottling off the kitchen counter. Aaarrrggggh!!!

Re: Oval-necked demijohn - fix/throw out ?

Posted: Wed Jul 11, 2018 12:20 pm
by Green Aura
elfcurry wrote:
Wed Jul 11, 2018 10:35 am
my lodger knocked a gallon of blackberry wine, ready for bottling off the kitchen counter.
Probably good legal grounds for eviction there. :lol:

I suppose as a last resort you could stretch a balloon over the neck and put a pin through it. I've never tried it myself but it might be worth - I'm sure balloons are cheaper than demijohns.

As for alternative uses, I saw an excellent idea for cutting one in half, inverting with a wick through the hole and making a small herb garden. Someone shared a similar idea for plastic bottles but I like the idea of a larger, more permanent, version. Unless your lodger's around, of course. :roll: :lol:

Re: Oval-necked demijohn - fix/throw out ?

Posted: Wed Jul 11, 2018 1:17 pm
by BernardSmith
So here's the secret, unless you are brewing beer the primary fermenter used for wine making does not need to be sealed. There is enough CO2 produced by the yeast to prevent any bacteria or other spoilage microbes from the air getting their way into the wine. All you need to do is cover the mouth with some cheese cloth or other material (so even a loose bung will work). Me? I use food grade buckets as my primary.
OK. If your carboy (demijohn) is made of glass and is not cracked or damaged but is leaking between the neck and the bung then I would assume that the problem is with the bung and not the glass. Try replacing the bung. If there IS an issue that a new bung cannot solve then get hold of some food grade silicone and squeeze a bead at the join. That will fix any "leak". The balloon (or better yet, a condom - easier if the neck is standard dimension) is also a reasonable solution..

Re: Oval-necked demijohn - fix/throw out ?

Posted: Wed Jul 11, 2018 3:15 pm
by Odsox
When I got some equipment a few years ago I mistakenly bought what I thought was an airlock bung. It looked like one but it fitted over the demijohn neck instead of inside (like a cork)
That might be what you want. ... 4023-p.asp
Forgot to add, they come in several different sizes.

Re: Oval-necked demijohn - fix/throw out ?

Posted: Thu Jul 12, 2018 9:19 am
by elfcurry
Thanks all for your thoughts and ideas.

Green Aura: he was extremely apologetic and offered to buy me some wine but I decided it wasn't replaceable, it was the time and effort I'd lost and commercial wine would be no recompense. Though I was very disappointed, it wasn't the only blackberry wine I made last year so it wasn't unique.

I like the balloon idea and may give it a go, though I'm wondering whether the rubber neck would stretch enough and the glass handles would get in the way making it less likely to remain in place. I can't visualise the herb garden or where to cut the glass or where the wick goes.

BernardSmith: for primary fermentation I use plastic kitchen 'cling film' on the container, held in place by string and rubber band, which works well. Two of my demijohns have oval necks. I know this because only these two fail to seal and I tried different bungs. Also it's clear on close visual inspection and one even dribbles water around a solid bung if inverted.

Some sort of sealant is the kind of solution I'd considered but don't know of anything which would allow a bung to fit and seal, and be removable, while not causing hygeine or other problems.

Odsox: I wasn't aware of the demijohn rubber caps but I'm pretty sure the handles would get in the way; they must be for a different design I think.
A friend some while ago offered me some demijohns but since said they aren't all 'pukka' but may include some bought containing cider and may not have the standard neck size, so I'm waiting to see them. If they're suitable, it's problem solved. In the meantime my two faulty ones comprise one borderline one which needs to be kept under observation and one definitely useless oval-necked one which I've labelled and put aside.

Re: Oval-necked demijohn - fix/throw out ?

Posted: Wed Jul 18, 2018 12:24 pm
by MKG
As Bernard has pointed out, no seal is required during fermentation - a loose cotton wool plug will stop insects getting in. When fermentation has finished, the enemy changes to the air itself - if oxygen gets in there, your wine will readily take it in and ... ermmm ... oxidise. However, any impermeable fabric covering the mouth of the demijohn and held on with an elastic band will stop that. Your demijohns aren't useless - they just need a bit of TLC.
If it's the lack of bubbling airlock which bothers you, I wouldn't worry about it - your wine will fall clear when fermentation has completely finished.

Re: Oval-necked demijohn - fix/throw out ?

Posted: Wed Jul 25, 2018 12:01 am
by Weedo
On another tack, I have two stoneware "demijohns", both of Oz manufacture. These came with the property and have been lazing about in various rooms trying to look decorative. One is stamped Number 2 and has the standard type bottle neck about 1 inch and the other is stamped Number 3 and has a wide mouth of about 6 inches. Does anyone know what the sizes are? I know I could measure them but I am in a lazy mood today

Re: Oval-necked demijohn - fix/throw out ?

Posted: Fri Aug 10, 2018 2:57 pm
by elfcurry
MKG, thanks for saying that. I didn't quite get from Bernard that the seal isn't as much an absolute requirement as I'd thought, for the complete fermentation - is that right? As a worrier though, I'd still be anxious about when it becomes important not to allow oxygen to enter. With an airlock you can easily tell how active the fermentation is from the frequency of glugging but it'd be much harder to tell from visible gassing of the wine in the jar. Do I worry too much? I just don't want to risk wasting fruit, time etc.

(Edit: is it just that while it's producing CO2 sufficiently, there's no opportunity or space for O2 ?)

Anyway, it's all academic now for me as the friend I mentioned came up trumps and gave me ten demijohns. Yes TEN! I haven't found a dud one yet and a couple are in use while the rest are waiting for something to put in them. The bottleneck (ha! considering thread title) is the lack of primary fermentation vessels as I usually use two old one (Imperial) gallon polythene ice cream tubs and I'm having to press other containers into use to feed the production line, now not limited by demijohn shortage.

I was wondering the other day what to do with my original two flawed (oval-necked) jars and thought a fun thing would be to keep tiny fish in one but make it look like wine is fermenting and keep it alongside actual wine to confuse and possibly amuse anyone looking at my wine. I'd need an air pump to aerate the water and simulate CO2 bubbling. Also where can I get tiny aquarium ornaments (shipwrecks, treasure chests etc.) small enough to fit the neck? (PS not a very serious suggestion)

Re: Oval-necked demijohn - fix/throw out ?

Posted: Fri Aug 10, 2018 8:29 pm
by BernardSmith
During active fermentation - which CAN take place in buckets loosely covered with towels to keep out dirt and pets... and kids.. the amount of CO2 expelled is more than enough to create a blanket of gas above the fruit and liquid. When fermentation slows and the gravity is around 1.005 (so still plenty of fermentable sugar to be fermented - assuming you are making wine with a total ABV of about 12-15% and so still well within the tolerance of any respectable yeast) THEN you want to rack (transfer by siphon - a siphon to reduce the amount of oxygen you introduce) the wine into a container with a narrow neck that you fill right up into that neck - to reduce the amount of oxygen you expose the wine to. Wine ain't beer and wine is not susceptible to "souring" because of lactic acid production in the same way that beer is (grain is full of lactic bacteria, fruit is full of yeast - and unless you want to use the indigenous yeast when making wine wine makers typically kill wild or indigenous yeast by applying K-meta. Brewers making beer kill the lactic bacteria by boiling the wort but as the wort cools it becomes a perfect haven , again, for lactic bacteria. Wine makers do not have this anxiety.