Fermenting in Corny?

I've picked up an under counter fridge this week so can finally begin some properly temp controlled fermentation.
Hoping to brew this weekend but looks like all my fermentors (standard 25-20L buckets) are too wide to fit in the fridge...

However, it will happily take a corny so I'm considering fermenting in a corny keg and then transferring into another corny to condition and serve.
Think I've read of others doing this and wondered if anyone could advise if the below sounds sensible.

Ferment in a standard 19L corny. Spunding valve attached to the gas post set to lowest setting possible to perform something like an airlock.

Temp control will be via an Inkbird taped to the side of the keg. Expect the temperature inside the keg to get a few degrees higher during active fermentation. Recipe is a best bitter, yeast will be WLP013, aiming for a temp of 19 degrees, so I guess Inkbird will need to be a couple of degrees lower initially. 17 in the first couple of days?

Diacetyl rest after a week -10 days then transfer to another corny keg to condition and serve.

Welcome any thoughts on this as I may have missed something blindingly obvious...

You can of course open ferment. The pressure relief valve on the lid will stay open.

Inkbird. Just dial in what you want (19c) and it will deal with it accordingly. What are you thinking 17c for 2 days?

MashBag said:

You can of course open ferment. The pressure relief valve on the lid will stay open.

Inkbird. Just dial in what you want (19c) and it will deal with it accordingly. What are you thinking 17c for 2 days?

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I did consider open fermenting, but feel I have a whole other bunch of questions about that..
Forgive a stupid question but how do you mean the PRV will stay open?

I was thinking set it to 17 degrees because the Inkbird prove will be in the fridge but outside the keg. Active fermentation will mean the temp inside the keg gets a little higher no?

You would need a floating dip tube to transfer out above the trub. Overall I would sooner just buy a fermenter that does fit.

Sometimes the PRV is a plastic lever or a ring pull, like the pic.

They can both be set in an open position. No need for a spunding valve unless you want to ferment under pressure.

Or if you are not dry hopping and the wort will be fairly clear...

You could ferment with the spundy set to something low and then when fermentation is over just 'serve' (using the pressure that has built up naturally) a litre or two into a jug (assuming the dip tube is the standard kind and goes right to the bottom) which will get rid of the crud. Then just condition in place. Saves faffing about with a transfer and there will be no O2 ingress. So rather than transfer the good stuff off the bad, just remove the bad.

By the way, I control the temperature of the fridge not the wort. So I'd just stick the probe somewhere in the fridge and set it to 17c. As you say the fermentation will push the wort up a couple of degrees which is fine. Cheaper on the leccy as you are not fighting fermentation.

Taking 1cm off the end of the dip tube with a 45° cut, is normally enough to deal with trub. A second hand corny makes a pretty good value stainless fv.

dlowe1992 said:

I was thinking set it to 17 degrees because the Inkbird prove will be in the fridge but outside the keg. Active fermentation will mean the temp inside the keg gets a little higher no?

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Gotcha.

You are controlling the ambient temp inside the fridge not a particular corny.

There might be a buffer effect, but you would still set 19. Set 17 and you will get 17 in the corny. Don't overthink it.

If the kitchen was 19, your fermenter running at 19. They equalise.


Edit :
Just seen your post @Twostage I would not have expected that. If that's what happens ignore me.

dlowe1992 said:

Ferment in a standard 19L corny. Spunding valve attached to the gas post set to lowest setting possible to perform something like an airlock.

Click to expand...

Or just take a post connector with a length of hose into a bottle of sanitiser.

MashBag said:

Sometimes the PRV is a plastic lever or a ring pull, like the pic.

They can both be set in an open position. No need for a spunding valve unless you want to ferment under pressure.

Click to expand...

Mine have the ring pull as per the pic.
Didn't know you could set in an open position. I'll definitely do that, thanks!

Yup, as you say, controlling the ambient temp @MashBag.

Twostage said:

Or if you are not dry hopping and the wort will be fairly clear...

You could ferment with the spundy set to something low and then when fermentation is over just 'serve' (using the pressure that has built up naturally) a litre or two into a jug (assuming the dip tube is the standard kind and goes right to the bottom) which will get rid of the crud. Then just condition in place. Saves faffing about with a transfer and there will be no O2 ingress. So rather than transfer the good stuff off the bad, just remove the bad.

By the way, I control the temperature of the fridge not the wort. So I'd just stick the probe somewhere in the fridge and set it to 17c. As you say the fermentation will push the wort up a couple of degrees which is fine. Cheaper on the leccy as you are not fighting fermentation.

Click to expand...

Thanks @Twostage, good to know controlling the fridge temp is workable.
Good point RE serving in situ. They're all standard dip tubes which reach the bottom. I've considered a floating one but haven't got round to getting one. There'll be no dry hop in this one, so it'll just be the usual sediment from fermentation. Think I might do this. Worst case scenario the dip tube blocks and I have to rack to another keg, which I was prepared to do anyway...

Any idea what setting to leave the spundy at?

dlowe1992 said:

Mine have the ring pull as per the pic.
Didn't know you could set in an open position. I'll definitely do that, thanks!

Yup, as you say, controlling the ambient temp @MashBag.



Thanks @Twostage, good to know controlling the fridge temp is workable.
Good point RE serving in situ. They're all standard dip tubes which reach the bottom. I've considered a floating one but haven't got round to getting one. There'll be no dry hop in this one, so it'll just be the usual sediment from fermentation. Think I might do this. Worst case scenario the dip tube blocks and I have to rack to another keg, which I was prepared to do anyway...

Any idea what setting to leave the spundy at?

Click to expand...

I was thinking just enough to push the gunk out, so maybe 10 max ?

(I've not actually done this before but it seems a good way of doing it. As I now have an empty corny (the very drinkable Poe's Boston bitter having run out ) I might do it myself)

Twostage said:

I was thinking just enough to push the gunk out, so maybe 10 max ?

(I've not actually done this before but it seems a good way of doing it. As I now have an empty corny (the very drinkable Poe's Boston bitter having run out ) I might do it myself)

Click to expand...

Yep, after I wrote this I thought 10 would make sense as it's also the level I'd set for carbonation on CO2 so, all things being equal, should end equally carbed. I'd like this to be quite softly carbed so I'll go a little lower, knowing I can top up on CO2 if needed.

dlowe1992 said:

Mine have the ring pull as per the pic.
Didn't know you could set in an open position. I'll definitely do that, thanks!

Click to expand...

Pull up and twist 90°

dlowe1992 said:

Yep, after I wrote this I thought 10 would make sense

Click to expand...

Did a bit with dispense from cornys. Get a reg with a knob.
Once full, install the lid and give it 30 or 40. Couple of toots of the safety and then reduce 5 or 10.
This seats the lid properly and gives a bit of a flush.

Full cornys keep for ages like this.

MashBag said:

Pull up and twist 90°

Click to expand...

Thanks! Didn’t know this

MashBag said:

Once full, install the lid and give it 30 or 40. Couple of toots of the safety and then reduce 5 or 10.

Click to expand...

Yeah this is what I usually do. Got quite paranoid my first keg was faulty til I realised you need the pressure to properly seat and seal the lid