Anyone Fermenting in a Corny Keg?

[Petrolhead]

I quite like the idea of fermenting in a corny keg and wondered if anyone had tried this.

I thought I could just drain the cooled wort directly into the keg, previously filled with CO2, add the yeast and pop in the brew fridge.

I would probably put a spunding valve on the keg set at say 2-3psi as a form of airlock and I read somewhere that this pressure can be increased during, or at some point, during fermentation.

I particularly like the idea of transferring the beer under pressure to the serving keg at the end of fermentation. I guess you could even do a couple of transfers if necessary for clarity as you aren’t introducing any oxygen.

With regard to the spunding valve I can’t see why I can use my CO2 set up. If I connect to the keg, set the valve at the desired pressure and then close the bottle valve I believe that as the pressure rises due to the fermentation the valve will release gas to maintain the desired pressure in the fermentation vessel/keg.

Any thoughts?

 

[-Bezza-]

Not much headroom, unless you're after a smaller volume? Is that even an issue of fermenting under pressure?

 

[Bigcol49]

Hi!
The advantage of fermenting under pressure is that the beer is carbonated when fermentation is finished. A closed transfer to your serving keg and your beer is fully carbonated and only needs to mature.
I have read that shortening the long dip tube by about 3cm helps to prevent the transfer of sediment.
There are lots of threads about this topic on this forum.

 

[Sadfield]

Yes, I've done a number of variations on this theme, depending on the type of beer I'm brewing. I've done a couple of complete fermentations in the keg, although I more often do a double drop, where I ferment in a plastic fv for a day or two, then move to corny. This drops most of the trub out, so I get less sediment in the keg. My next project is to do this with an initial open and shallow fv. I also do this with mixed fermentation beers, starting with Saccharomyces in the plastic fv, then add Brettanomyces and/or bacteria in the keg. Fermenting in the keg is great for NEIPAs where hops are added with the yeast, once you find a way filter the hops.

Fermenting under pressure reduces esters, this is great for cleaner styles, and allows fermentation at higher temperatures.

 

[HarryFlatters]

I think German brewers have to ferment in a closed vessel as force carbonation with gas not produced as part of fermentation isn't allowed under Reinheitsgebot.

I might give it a go with the next German style I make.

 

[xozzx]

previously filled with CO2, add the yeast and pop in the brew fridge.

When you add the chilled wort you want as much oxygen as possible, flushing the keg with CO2 would not be a good plan.

 

[peebee]

I do it lots, but so far I've only done it for low-alcohol beers (<2%). I use regulators as spunding valves too. But I have them set to maintain 12PSI (set to about 7-8PSI, they "relieve" at 4-5PSI over-pressure), which they can do because they are pretty decent regulators. Setting spunding valves for 2-3PSI is cloud cuckoo land.

Although someone did point these out to me: https://www.aliexpress.com/store/pr...l?spm=a2g0v.12010108.1000001.7.15fb5280PduKjr

I had a long discussion on "spunding" valves here: https://www.thehomebrewforum.co.uk/threads/regulators-as-spunding-valves.74958/

 

[HarryFlatters]

When you add the chilled wort you want as much oxygen as possible, flushing the keg with CO2 would not be a good plan.

Dissolved into the wort, not in the headspace of the keg or fermenting vessel. I think.

 

[Petrolhead]

Thanks for some great ideas and advice. Really dumb of me to say to fill the keg with CO2 so thanks xozzx.

The headspace is really worth some thought as you say Bezza. If you were fermenting at a high pressure this wouldn’t mattter as the liquid is retained in the keg but as I understand it you have to start fermenting at a low pressure but I may be wrong.

 

[peebee]

Thanks for some great ideas and advice. Really dumb of me to say to fill the keg with CO2 so thanks xozzx.

The headspace is really worth some thought as you say Bezza. If you were fermenting at a high pressure this wouldn’t mattter as the liquid is retained in the keg but as I understand it you have to start fermenting at a low pressure but I may be wrong.

Because I use regulators as spunding valves (which is what you said you'd like to do) the keg gets pressured to 7-8 PSI as soon as the spunding valve is attached. I don't see it as a problem? Note if using a regulator the CO2 still has to be attached because without the back-pressure the regulator will probably vent all the pressure in the keg

As I use dried yeast and SG is below 1.050 there's no need to aerate the wort anyway.

The headspace could be an issue because if the "krausen" gets too high it will force itself into the spunding valve (not good if using a regulator). But it is mitigated somewhat by pressure reducing the head that can form over the beer.

 

[Tunabeast]

Tempted to give this a go.

Has anyone reduced the length of the liquid out dip tube to reduce pick up of yeast/trub?

 

[Sadfield]

I usually start from

Tempted to give this a go.

Has anyone reduced the length of the liquid out dip tube to reduce pick up of yeast/trub?

Yes, although partly to accommodate a filter for dry hopping. I bought a spare for around £8.

I found this article informative when I started fermenting in keg.

http://scottjanish.com/fermenting-dry-hopping-pressure/

 

[Tunabeast]

I usually start from


Yes, although partly to accommodate a filter for dry hopping. I bought a spare for around £8.

I found this article informative when I started fermenting in keg.

http://scottjanish.com/fermenting-dry-hopping-pressure/

Very interesting article thanks.

Struggling to find a replacement dip tube, where did you get one from?

Also what type of filter arrangement did you use?

 

[Sadfield]

Brewuk, although I had to bend it straight for my kegs. It was also too long, so needed cutting anyway. It's cut at 45° so the base of the filter can't cap the end.

I use the same setup as in the article for filtering. I rack to another keg for serving/bottling, post dry hop.

 

[F00b4r]

I do it lots, but so far I've only done it for low-alcohol beers (<2%). I use regulators as spunding valves too. But I have them set to maintain 12PSI (set to about 7-8PSI, they "relieve" at 4-5PSI over-pressure), which they can do because they are pretty decent regulators. Setting spunding valves for 2-3PSI is cloud cuckoo land.

Although someone did point these out to me: https://www.aliexpress.com/store/pr...l?spm=a2g0v.12010108.1000001.7.15fb5280PduKjr

I had a long discussion on "spunding" valves here: https://www.thehomebrewforum.co.uk/threads/regulators-as-spunding-valves.74958/

The "Spundit" diaphragm based valve in that thread has ended up working extremely well and is very easy to configure accurately to what you want, my current beer I had it at just 2 PSI for the bulk of the ferment and then raised it to carbonate the beer with the last gravity points and ensure that I can crash chill my Fermentasaurus in a completely closed system without it collapsing.
If you have to import it from the USA, i.e. don't have a trip over there planned or visitors coming over, the postage is expensive but the guy appears to have improved on the design a little and it is so much better than the poppet design one I have. I quite like the regulators you use but once you add in the extra CO2 bottle etc it becomes a bit of a faff and I'm guessing negates any monetary savings. A group buy on either the Spundit valves or the diaphragms they are based on could be interesting.

 

[DrGMc]

Just seen this topic but yes like Sadfield I've only done double drops to minimise sediment. Had two great oktoberfests this year (one dark and one wheat) and a plum porter and all gave great head . I must add the spunding valve as Peebee suggests (kind of) as I've got one but never thought to use it.
I must also act on shortening the dip tube as I've thought about it but chickened out and just tilted the keg on a step of wood.
Great question Petrolhead and this forum always makes me think how to do better and provides that challenge

 

[Petrolhead]

I’m really keen to try this and there is loads to think about in this thread.

The headspace issue is giving me a bit of thought. I could use a primary fv but I feel that at just the point you want to start reducing exposure to oxygen and possible contamination you do exactly that. At the moment it occurs to me that the best route would be to fix a blow of tube to the corny for a day or two. At this point you would only be wanting to keep the corny at a couple of pounds pressure anyway and then remove it and seal the corny whilst controlling the pressure with the spunding valve or your regulator.

I also like DrGMc’s idea of tilting the keg over, as I do that with my current fv, at some point you can then move the beer into a second keg leaving a fair amount of true behind.

 

[DrGMc]

Petrolhead
yep eou've even got me thingking that I couolf transfer to to a second vessel (keg) in that I could exclude oxygen and still have a beer with less trub (by leving the primary vessel tilted) and transferring under pressure to a second Corny ....
good grief this might be a way of creating a great head with little sediment - damn why didn't I think of this before ...