Keg type for a conversation

[wilfh]

I want to convert a 50l keg into a fermenter but I’m confused about the fittings on the keg. They all have a 2inch outlet at the top but lots of different couplers.
Is each keg specific to to coupler or can they be taken off just leaving a round hole for a bung. I intend to take out the spear ect and wont be fermenting under pressure.
Thanks
Wilf

[Kev888]

All my crusader kegs have an inside neck diameter of about 49mm; they're supplied with s-type spears. I've only ever measured one keg that wasn't an s-type and that was the same (though sadly I don't know if it means they all are).

S-type seem by far the most common in homebrewing though, partly because thats what are available to us, so IMO would be the one to go for unless you have reason otherwise - e.g. in case you ever need to swap or sell on. Sadly most used kegs listed on ebay are still owned by the brewery and so not actually the seller's property to sell, though you do very occasionally see legitimate sales where e.g. a brewery is selling them or else one has closed down.

That said, the necks are internally threaded, so not sure how well a bung might seal. Well enough to keep flies out certainly, but not sure if well enough for an airlock or if you wanted to exclude oxygen after fermentation finished.

It is fairly common (especially amongst overseas distillers) to use 2" tri-clamp fittings on the rims of the neck, with a bit of adjustment to the seal. 2" tri-clamps fit 64mm diameter ferrules, which isn't far off the keg's neck rim diameter. I have done this with some of mine to use them as fermenters and it does work, though of course the neck isn't really designed for it so it is a slight fudge that needs care when clamping up to keep alignment.

[wilfh]

Thanks Kev,
Just what I am looking for. I didn’t know about the ownership. Something to bear in mind. Was going to give the triclamp idea a run and see if it was ok.
Wilf

[Kev888]

No worries. I should have mentioned that one other option is to use a coupler and ferment with the spear in. If one removes the one-way valve in the gas side of the coupler (and caps the beer outlet) then a blow-off tube or airlock etc can be fitted to it.

There is more gubbins to clean with the spear and coupler involved, but it is simpler to set up. Plus if you're a CO2 user then it means you can do a pressure transfer afterwards if wished - much like would be done when dispensing beer. Personally I made a bespoke dip-tube affair (instead of using the spear and coupler), based around a tri-clamp ferrule, but the principle is similar.

[TheSumOfAllBeers]

The malt miller sell a bespoke part that fits corny posts onto a 2” tri clamp ferrule, it has a flexible dip tube that you could attach a cask widge float onto, which would be very handy for these sankey -> fermenter conversions.

I am looking to get into this for pressure fermentation.

A good source of kegs could be small breweries: the kegs maybe a bit worn and not something they would trust their beer to, but would still function well as a fermenter

[wilfh]

The malt miller sell a bespoke part that fits corny posts onto a 2” tri clamp ferrule, it has a flexible dip tube that you could attach a cask widge float onto, which would be very handy for these sankey -> fermenter conversions.

I am looking to get into this for pressure fermentation.

A good source of kegs could be small breweries: the kegs maybe a bit worn and not something they would trust their beer to, but would still function well as a fermenter

Thanks- will have a look