Bulk Conditioning in Kegs

[Cloud Surfer]

I’ve been thinking of ways to get the most out of my one temperature controlled fermenter. All my beers will generally be big ABV types that I want to bulk condition post primary. But I’ve decided that tying up my fermenter for 8 to 10 weeks per beer is not the best way to make lots of beer.

My biggest concern with transferring to a second container for conditioning and leaving it there for months is oxidation. So, if I were to purge a keg with CO2 then pressure transfer from the fermenter into the keg, I think that might be a good solution. But I’ve not done this before, so want to check if there’s any reason why you can’t bulk condition in a keg. I have a spare fridge to keep the keg at conditioning temp and then I can turn it down for cold crashing before bottling.

At bottling I thought I could purge another keg, put the priming solution in it, and then pressure transfer the conditioned beer into the bottling keg. Then use a bottling gun to bottle. So just trying to come up with a fairly oxygen free process of getting the beer from primary into the bottle. I’m sure lots of people have done stuff like this, so hopefully the advice is I’m on the right track. If this works, I’ll be able to get a new beer into the fermenter every 4 or 5 weeks which will make much better use of it, and give me more of the tasty stuff to drink.

 

[Cloud Surfer]

So cutting through the long post, is there any reason why I can’t/shouldn’t bulk condition in keg?

 

[razz]

No. I would transfer to the keg when you have maybe 4-5 gravity points left to ferment. That way you will get the keg carbonated with out using CO2.

 

[Cloud Surfer]

That’s a good idea. Though I’ll be using CO2 to pressure transfer, and was going to purge the keg as well. But a small amount of carbonation pressure could be good.

 

[kadmium]

The problem with racking off the gross lees (or the yeast colony) with fermentation still underway is stalling it out. It can also stress the yeast, which may result in a less than ideal diacetyl rest. Especially if you're racking off the yeast and then pressurising them, after a high gravity stressful fermentation.

It could be fine or it could cause issues. There is no reason you can't age in the keg, but it also depends on how you want to carb. If you want to naturally carb in the keg, I would wait till fermentation is over, bulk prime the keg and rack into it. Wait 3 weeks and then bottle.

Honestly, I don't see an advantage in bulk aging before bottling. The only way I would do it is if I was going to do it in a barrel. You could look at buying a 20L wooden barrel for barrel aging, but I would think after you reach FG you should rest a few days, crash and transfer. Then prime and bottle or however you will do it.

Bulk aging is usually something you do for meads because they age 6+ months in bulk. But they are usually 16+% and need to really mellow out the hot alcohol taste.

Even a 9% RIS or a quad or something, are usually aged in the bottles. So consider a 2 week ferment with a rest, straight into bottling.

 

[MHB]

If you want to get extremely low DO just purging the keg wont get you there, there is a fairly good write up on it on the BYO website plus lots more if you do a bit of reading up on LODO brewing.
The best (lowest DO) method is to fill the keg with deaired water (boiled fill while hot allow to cool with CO2 overpressure, bubble N2 through the water, ad some Metabisulfite... lots of options) then use CO2 to blow the water out of the keg. This will get you lower O2 in the keg than would half a dozen pressurise and purge cycles.

If you have a read of Braukaiser he goes through the maths on exactly when to transfer. Well you might have to do a bit of rearranging, but its worth reading the whole section on fermentation.
Mark

 

[kadmium]

LODO is not worth it to that extent in my opinion. Filling with starsan and pushing it out can't leave huge amounts of o2 in the keg surely.

 

[Garfield]

If you're conditioning in the keg then O2 isn't going to be a problem anyway.

Personally I would only keg condition if I'm leaving it in the keg for good. If you're looking to bottle then there's no need to add a step. Let it ferment out, cold settle if you want, then bottle it and leave to condition for desired period. Simple and effective

 

[Cloud Surfer]

My early background was in the wine industry, assisting wine makers to make wine. Over the past 20 years its been about drinking lots of beer and wine around the world. So while I know nothing about making beer, I do know a bit about conditioning and maturing wine and beer.

I agree there’s absolutely nothing wrong with conditioning and maturing beer in bottle, but it’s accepted that doing it in bulk is more optimal when we are talking high ABV beer. You will get a better product sooner. But it’s expensive and time consuming which is why most everyone avoids doing it. There are a lot of craft breweries in the US making incredible RIS and their flagship brews all get bulk conditioning before bottling.

So it’s a process I enjoy as much as the other processes involved in making beer, so I will utilise it when I make the big ABV beers. I like all the information though, I’m learning a lot.

 

[kadmium]

My early background was in the wine industry, assisting wine makers to make wine. Over the past 20 years its been about drinking lots of beer and wine around the world. So while I know nothing about making beer, I do know a bit about conditioning and maturing wine and beer.

I agree there’s absolutely nothing wrong with conditioning and maturing beer in bottle, but it’s accepted that doing it in bulk is more optimal when we are talking high ABV beer. You will get a better product sooner. But it’s expensive and time consuming which is why most everyone avoids doing it. There are a lot of craft breweries in the US making incredible RIS and their flagship brews all get bulk conditioning before bottling.

So it’s a process I enjoy as much as the other processes involved in making beer, so I will utilise it when I make the big ABV beers. I like all the information though, I’m learning a lot.

Good view on things! And goes to show there are lots of little things to get out of this hobby. I reckon you go head first into it and buy yourself a 20L barrel and do a barrel aged quad. Then send me some so I can check if it's ok. And by some I mean ship the barrel to me.

 

[The Brew Master]

Cloud Surfer,

Just remember if you decide to condition your beer in a keg you will not need the same amount of priming that you would use if bottle priming. I use 75g - 80g of sugar per 19 litre keg.

 

[Garfield]

Cloud Surfer,

Just remember if you decide to condition your beer in a keg you will not need the same amount of priming that you would use if bottle priming. I use 75g - 80g of sugar per 19 litre keg.

If we're bulk priming in keg then pressure transfer would be at peak carbonation anyway. You could French is up with a very well calculated dosàge if needed


@Cloud Surfer whats the advantage of bulk priming in commercial wine making? For us (my background too) it was the economics of completing as much of the process in the vat before tying up barrels or starting a bottling run. We didn't make sparkling onsite though

 

[Cloud Surfer]

Good view on things! And goes to show there are lots of little things to get out of this hobby. I reckon you go head first into it and buy yourself a 20L barrel and do a barrel aged quad. Then send me some so I can check if it's ok. And by some I mean ship the barrel to me.

Mate, after all your help you deserve the first barrel.

 

[Cloud Surfer]

Cloud Surfer,

Just remember if you decide to condition your beer in a keg you will not need the same amount of priming that you would use if bottle priming. I use 75g - 80g of sugar per 19 litre keg.

I’m trying to understand this one. I wasn’t planning on holding the keg under constant CO2. Just purging and making sure the headspace is filled with CO2, and then leaving the keg sealed as is. Is that enough to affect the volume of CO2 in the beer prior to priming for bottling?

 

[Cloud Surfer]

If we're bulk priming in keg then pressure transfer would be at peak carbonation anyway. You could French is up with a very well calculated dosàge if needed

My thought is to transfer from the conditioning keg to a second keg for bulk priming, and then under pressure using a beer bottling gun to bottle. So the beer is only in the bottling keg for 30 minutes or so, and carbonation still happens in bottle. My whole thought process is around oxygen minimisation all the way through to bottling.

 

[Cloud Surfer]

@Cloud Surfer whats the advantage of bulk priming in commercial wine making? For us (my background too) it was the economics of completing as much of the process in the vat before tying up barrels or starting a bottling run. We didn't make sparkling onsite though

Do you mean bulk conditioning? In a similar way to big, complex beer, there’s so many elements in wine that are unbalanced when it is first produced. The tannin structure especially makes big wine undrinkable to begin with. Bulk conditioning in the big tanks speeds up the process, so the wine can then go through barrel or to bottling quicker, rather than the winery going straight into bottle and then have stock laying around for an extended period waiting for it to become commercially acceptable to drink.

 

[Garfield]

I think oxidation in beer gets way to much attention. I'm a fairly careless brewer and I've never lost a batch to O2. Especially since you're bottle priming, you'll find most O2 is converted by yeast. Because wine isn't made this way (methode champagnoise exempt) and is handled at low temp in vats that don't seal near as well as beer kegs, are regularly opened and played with, etc... They are vulnerable to dissolving O2. Generally managed with sulphur additions and some co 2 purging.



On your note about leaving in keg to condition with a co2 purge. Be aware this will start to carbonate anyway. Even with finished beer at terminal, the yeast seem to make co2 in the keg. This isn't consistent with brew talk but I promise you I observe it everytime.



Yeah I finally got what you mean in the winery. Conditioning means maturing in winemaking, but it in brewing it means carbonating. This is where I got confused. What exactly did you do in tank to "speed up process" anyway?



Finally (sorry a lot of thoughts), if you're taking about high ABV beers, why can't they condition in the bottle??

 

[kadmium]

I think oxidation in beer gets way to much attention. I'm a fairly careless brewer and I've never lost a batch to O2. Especially since you're bottle priming, you'll find most O2 is converted by yeast. Because wine isn't made this way (methode champagnoise exempt) and is handled at low temp in vats that don't seal near as well as beer kegs, are regularly opened and played with, etc... They are vulnerable to dissolving O2. Generally managed with sulphur additions and some co 2 purging.



On your note about leaving in keg to condition with a co2 purge. Be aware this will start to carbonate anyway. Even with finished beer at terminal, the yeast seem to make co2 in the keg. This isn't consistent with brew talk but I promise you I observe it everytime.



Yeah I finally got what you mean in the winery. Conditioning means maturing in winemaking, but it in brewing it means carbonating. This is where I got confused. What exactly did you do in tank to "speed up process" anyway?



Finally (sorry a lot of thoughts), if you're taking about high ABV beers, why can't they condition in the bottle??

Oxidation in bottles is definitely a thing. It is style dependant, but more hops means more prone.

Oxygen introduced while bottling will do damage waaaaaaaaaaaaaay before the yeast "scrub" or what ever people think they do.

Hoppy Hazy IPAs especially those big on aroma and flavour of fruit / citrus are more susceptible than even the classic IPA styles of pine/bitterness but they still are.

Beers with lower hops are less susceptible. I perceive the flavour as a wet cardboard type. Not something enjoyable. It also clearly destroys hop aroma and flavour.

I brewed a Galaxy SMaSH beer. Bottled it. 2 weeks in it was perfectly carbed, hazy, hoppy passionfruit citrus delight.

Another 1 week later it was a copper colour and very muted in hop aroma and flavour.

 

[MHB]

Could post this in either of Cloud Surfers threads as they are pretty strongly related.
Had a look in the Almanac, it gives process instructions for most of the beers. Those for Dubbel and Tripel are basically the same.
Remembering that these are written for commercial brewing and you can safely assume that they are talking about pretty big yeast pitches (huge) compared to what most home brewers use, you might need to go a little slower or build up your yeast stocks.

Primary Ferment 5-7days at 15-21oC Depending on yeast strain.
Rack to Secondary fermentation 3-5 weeks at 8-10oC.
Dissolve and sterilise 250g/hectoliter of beer, white sugar...

(I would get off the yeast at this stage, either dump in a CCV, rack or transfer keg to keg leaving the old yeast and trub behind. Note that 250g/hL is only 1.2g/L of CO2)

Add to beer and re-inoculate with fresh yeast. Condition in closed tank for a day.
Package. Bottle condition 3weeks at around 21oC.
Age the beer in bottle for 3-4 Months in a dark cellar at 10-15oC

Looks like they aren't relying on developing all the carbonation in the secondary so its more a maturation step, I suspect not holding the beer under full pressure at this stage allows for the end of fermentation being fairly drawn out in big beers and for the release of some undesirable volatiles, some overpressure during maturation would be the best option.
Most Belgian Ales are carbonated at 3.8-4.8g/L (Braukaiser). The recommended sugar addition only supplies about 1.2g/L so it looks like an overpressure around 80-100kPa (0.8-1 Bar) would be necessary at the maturation temperature (8-10oC) to get the right amount of fizz.
I'm far from sure that pressure fermenting Ales is a good idea, suspect there could be some real downsides to too much pressure during maturation. As Garfield noted maturation and carbonation are often covered by the catch all term "Condition" this is largely right in lower gravity beers but where both can happen together, its useful to think about them separately when you are making big beers.

Cardboard is one of those flavours no one likes, its most often associated with trans-2-nonenal, that's another whole conversation that involves HSA, wort lipid content and funny concepts like non-oxygen oxidisation caused by lipoxygenase... Would recommend reading George Fix Principles of Brewing Science if its a real issue.
Have seen a NEPIA go from great to dishwater in a week, primarily from O2 picked up on a bad filter run, well more of a sieving run, so much hops in the keg it was blocking up the keg coupler, so ya late O2 is something to watch out for to - especially in highly hopped beers.
Mark

 

[goatchop41]

If you're conditioning in the keg then O2 isn't going to be a problem anyway

I think oxidation in beer gets way to much attention. Especially since you're bottle priming, you'll find most O2 is converted by yeast

Two pretty horrendous takes here. Both incorrect.

Conditioning in a keg doesn't magically mean that the O2 that can introduced during the transfer/racking process disappears and doesn't affect the beer. So that's point 1 out the window.

I always question this often repeated mantra that yeast will consume all of the O2 that is introduced during the bottling process - I've never been able to find any research to back up the claim, nor any to suggest that the yeast even require that O2 at that point in order to complete the bottle priming process.
Making/repeating this claim also completely ignores the fact that even if the yeast did consume all of the O2 in the headspace, that O2 has already caused oxidation reactions within the beer while it has been in contact with the beer from the point of packaging until the time that the yeast supposedly consume it.

I'm a fairly careless brewer and I've never lost a batch to O2

There is a big difference between a batch being completely ruined by oxidation vs oxidation making it a sub-par end product, and you've completely glossed over that.
My opinion is that any homebrewer who claims that they have never been affected by oxidation just simply doesn't know what it is, or is completely unable to recognise/detect how it is affecting their beer. Unless you have been going the absolute whole hog from the very start of your homebrewing adventures in terms of having a perfect process throughout your brewing, then you've definitely going to have had beers that were affected by oxidation. If you think that you didn't, then you either don't know what to look for, are being wilfully ignorant, or suffering from the Dunning-Kruger effect