Is there such thing as a spunding valve for a demijohn or swing-top bottle?

I want to make elderflower champagne for the second time. Last year it was fermented in plastic bottles, and one of them exploded. I figured there must be some sort of equivalent of an airlock that releases above a certain pressure, and thus I discovered that spunding valves are a thing.

However, it seems that spunding valves are made only for kegs, and specialised pressurised fermentation vessles.

Does such a thing exist for glass swing-top bottles or demijohns? Is this a silly question, and am I missing a reason why this would be non-sensical?

Apologies if this is daft. I'm totally new to this, having made elderflower champagne once before, and nettle 'beer' a few weeks ago.

1 Answer 1


I've never seen an off-the-shelf glass/plastic bottle with a variable pressure release (spunding valve..that's a new one to me!) I could be wrong, there's all kinds of neato gadgets these days. I think you'd have a hard time getting anything to attach to a swing top bottle that isn't the swing top.

I think you could do it though..but not in a swingtop. You could build your own spunding valve (there's some DIY guides online) or there are some distributors (in the US at least) that are selling something that would act as a spunding valve with a valve release off a ball-valve gas input. You could potentially use one with a ball-valve carbonation cap that screws onto 2 liter bottles (they make these and they're ~$10 USD). That should work in theory...but I've certainly never tried anything similar.

Also, it's really not a silly question. There's a lot of people that just want to make really simple and sweeter fermented sparkling beverages and being able to do something like this on a 2 liter would certainly be novel.

It would certainly be easier to do this with stainless steel kegs but that can be cost/space prohibitive.

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