Room temp counter pressure bottling

[Bark0s]

I got into pressure fermenting for one reason, I was curious about brewing lagers and I don't have space to chill a fermenter. What I didn't realise was that when it comes time to bottle from a kegmenter (or pressure ferment vessel) that standard wisdom says I need to chill the beer anyway.

I decided to experiment with room temperature carbonation and room temperature bottling.

I fully expected to pour foam and nothing else until I thought about 3 things:
1. When I see a canning line, they don't fill under pressure, they do fill very cold and they flush the can with CO2 and cap on foam
2. Gas goes in and out of solution in a liquid more easily when that liquid is at a higher temp - although the capacity to hold gas is better at lower temps.
3. Another bit of wisdom that people are taught when bottling from cold kegs is to chill the bottles - because deltas in temp are a problem.

I 'theorised' that with a counter pressure bottle filler, where the keg had been naturally carbonated to 10 psi with fermentation, topped up to 22 psi for 16 hours with CO2 (all at 18-20 degrees) I'd be able to fill bottles without foam because I had no change in pressure and no change in temperature. 2.2 volumes of CO2 @ 18 degrees requires 22 psi.

Turns out I was correct.

Last night I bottled at 22psi, it ran in nicely and slowly, stayed as a liquid (sure I had to apply a bit of pressure to keep the bottle filler sealed into the bottle). Once filled I bled out most of the pressure, then capped on foam. Sampled a chilled beer last and it was great.

Chilling may not be essential for bottling after all.

 

[MHB]

Two minor points
Re:-
2. Gas goes in and out of solution in a liquid more easily when that liquid is at a higher temp - although the capacity to hold gas is better at lower temps.
Not quite, it sure comes out faster (open a warm can of coke) but it is much harder to get it into a warm liquid.

Which sort of leads to the second point.
I doubt that 150kPa for 16 hours would be anything like enough to reach equilibrium ar or around 20oC, that to is something that happens faster colder. Odds on you haven’t got anywhere near the amount of dissolved CO2 you think you have.
At a guestimate I would think 3-4 days would be a minimum, probably longer.

Not saying it isnt possible, just be a lot harder to do warm consistently than it would be colder.
If you rinse the bottles with water (maybe just a pinch of Merabisulfite wouldnt hurt) before pressurising and filling it will reduce breaking out (foam forming in the bottle) as it will remove dust and other fines that could act as nucleating points.
Mark

 

[duncbrewer]

@Bark0s
I regularly pressure ferment and go higher pressure wise in the fermenter to try and get the carbonation correct. Often need about 25 psi at say 20 celsius. Doesn't stop the ferment. I normally start with low pressure and then let it ramp up after about 3 days to these higher pressures.
I don't bother to chill the bottles, do have a final rinse with sod met after the starsan as a sort of antioxidant makes me feel better.
The williams warn counter pressure copes well with this. If the fermenter is in the fridge and has been chilled / cold crashed I go for it as well.
I find that you do get some pressure loss in the bottling so if it says 2.4 for style I aim 2.6 in fermenter and then it seems okay in the bottle.
Keg can always be adjusted or balances with time. But the extra bit of free pressure helps with the closed transfer as well.

 

[Bark0s]

Two minor points
Re:-
2. Gas goes in and out of solution in a liquid more easily when that liquid is at a higher temp - although the capacity to hold gas is better at lower temps.
Not quite, it sure comes out faster (open a warm can of coke) but it is much harder to get it into a warm liquid.

Which sort of leads to the second point.
I doubt that 150kPa for 16 hours would be anything like enough to reach equilibrium ar or around 20oC, that to is something that happens faster colder. Odds on you haven’t got anywhere near the amount of dissolved CO2 you think you have.
At a guestimate I would think 3-4 days would be a minimum, probably longer.

Not saying it isnt possible, just be a lot harder to do warm consistently than it would be colder.
If you rinse the bottles with water (maybe just a pinch of Merabisulfite wouldnt hurt) before pressurising and filling it will reduce breaking out (foam forming in the bottle) as it will remove dust and other fines that could act as nucleating points.
Mark

I'm more than happy to take all that on board...

I guess it's about checking sources...I'm sure I saw somewhere that 22 psi for 16 hours will carbonate beer to 2.2 volumes. (I'm not saying it was a valid source) but at low temps, you need only 10 or 12 psi but it takes a week.

 

[duncbrewer]

@Bark0s
That psi reading depends on the temperature.
I find this tool helpful when pressure fermenting
https://drhansbrewery.com/beercarbonationcalculator/
You'll save a lot of CO2 if the yeast make it for you and you use it.

 

[MHB]

I'm more than happy to take all that on board...

I guess it's about checking sources...I'm sure I saw somewhere that 22 psi for 16 hours will carbonate beer to 2.2 volumes. (I'm not saying it was a valid source) but at low temps, you need only 10 or 12 psi but it takes a week.

I would check the source, frankly that’s totally arse about.
Good rule of thumb
Colder goes in faster and more goes in, comes out slower.
Warmer goes in slower and less goes in, comes out faster.

What might have been a bit confusing is that at the same pressure, the solubility is so much lower that you might reach the equilibrium point pretty quickly as its going to be at a lot lower level of dissolved CO2.

Note that the target dissolved CO2 for a lager is generally given as 4.4-5.4g/L (that’s 2.2-2.7Vols). From memory CUB and Tooheys both condition their mainstream lagers to ~4.75g/L.
You are right at the bottom (or under) of the range, the more you want in the beer the harder it will be to manage.
It would be interesting to measure the amount of dissolved CO2 you actually have, could be worth doing.
Mark

 

[Bark0s]

I would check the source, frankly that’s totally arse about.
Good rule of thumb
Colder goes in faster and more goes in, comes out slower.
Warmer goes in slower and less goes in, comes out faster.

What might have been a bit confusing is that at the same pressure, the solubility is so much lower that you might reach the equilibrium point pretty quickly as its going to be at a lot lower level of dissolved CO2.

Note that the target dissolved CO2 for a lager is generally given as 4.4-5.4g/L (that’s 2.2-2.7Vols). From memory CUB and Tooheys both condition their mainstream lagers to ~4.75g/L.
You are right at the bottom (or under) of the range, the more you want in the beer the harder it will be to manage.
It would be interesting to measure the amount of dissolved CO2 you actually have, could be worth doing.
Mark

Thanks Mark, great info.

how do I measure the actual dissolved co2?

 

[Bark0s]

@Bark0s
That psi reading depends on the temperature.
I find this tool helpful when pressure fermenting
https://drhansbrewery.com/beercarbonationcalculator/
You'll save a lot of CO2 if the yeast make it for you and you use it.

I’ve seen similar calculators and charts but all of them lack time as a variable/3rd axis.

 

[MHB]

You never will because time isn’t a variable it’s a dependant. Given we have a set temperature and pressure. The time required will then depend on the surface area (interface) and the volume of liquid to be carbonated.

In a tall thin keg say a corny, the surface area is the same from say 2L to 19L, pretty obviously if you had 2L it will reach condition a lot faster (roughly 9.5 times faster) than it would if the keg was full.

Using an air stone to make lots of small bubbles (increase the interface area) will speed up the dissolution. That’s pretty much what is done in industry. Use an air stone, trickle the gas through, let the first bit escape to purge any O2 in the head space, then close the tank (have a good PRV) and let the CO2 absorb.

As well as the other factors, how close to condition you are will matter, when there is a big differential gas moves into solution faster, when you are close to equilibrium the rate of transfer will get slower and slower.
Fizz isn’t a simple subject.

Measuring CO2 is pretty easy.
Take a scale +1kg with a 0.1g resolution would be a good call.
Weigh a bottle of beer and a container big enough to hold the bottle (I use an 800mL beaker)
Open the bottle carefully - don’t spill any even drops matter and pour into the container.
I put the container in a cheap ultrasound cleaner for about 15 minutes, you could just cover and leave for 12 hours or so for all the excess CO2 to evolve.
Weigh the whole thing again (dont forget the cap, that will really scrute up the calks)
Record mass of CO2 that has evolved.
Remember you need to get the volume very accurately, easiest is to have marked the beer level in the bottle, empty and clean the bottle weigh, fill with pure water to mark and re-weigh.
Gives you the mass of CO2 and the mass (~volume) of beer, gives you g/L dissolved CO2, which is how everyone outside the US (and misguided home brewers) measures Fizz.
Don’t forget if you work out you has 375mL of beer and it was at 20oC, you need to go look at the table to work out how much CO2 is still in the beer at 20oC and add that to what evolved.
If you want the answers in pounds shillings and pence you on your own.
Mark

 

[Bark0s]

You never will because time isn’t a variable it’s a dependant. Given we have a set temperature and pressure. The time required will then depend on the surface area (interface) and the volume of liquid to be carbonated.

In a tall thin keg say a corny, the surface area is the same from say 2L to 19L, pretty obviously if you had 2L it will reach condition a lot faster (roughly 9.5 times faster) than it would if the keg was full.

Using an air stone to make lots of small bubbles (increase the interface area) will speed up the dissolution. That’s pretty much what is done in industry. Use an air stone, trickle the gas through, let the first bit escape to purge any O2 in the head space, then close the tank (have a good PRV) and let the CO2 absorb.

As well as the other factors, how close to condition you are will matter, when there is a big differential gas moves into solution faster, when you are close to equilibrium the rate of transfer will get slower and slower.
Fizz isn’t a simple subject.

Measuring CO2 is pretty easy.
Take a scale +1kg with a 0.1g resolution would be a good call.
Weigh a bottle of beer and a container big enough to hold the bottle (I use an 800mL beaker)
Open the bottle carefully - don’t spill any even drops matter and pour into the container.
I put the container in a cheap ultrasound cleaner for about 15 minutes, you could just cover and leave for 12 hours or so for all the excess CO2 to evolve.
Weigh the whole thing again (dont forget the cap, that will really scrute up the calks)
Record mass of CO2 that has evolved.
Remember you need to get the volume very accurately, easiest is to have marked the beer level in the bottle, empty and clean the bottle weigh, fill with pure water to mark and re-weigh.
Gives you the mass of CO2 and the mass (~volume) of beer, gives you g/L dissolved CO2, which is how everyone outside the US (and misguided home brewers) measures Fizz.
Don’t forget if you work out you has 375mL of beer and it was at 20oC, you need to go look at the table to work out how much CO2 is still in the beer at 20oC and add that to what evolved.
If you want the answers in pounds shillings and pence you on your own.
Mark

Thanks Mark, I will try that measurement.

Sadly for me, you were right about having the amount of CO2 all wrong. I opened a well chilled bottle tonight and it's might flat.

Bugger.

I'll test one more tomorrow and if it's the same then I'll have to hit them with carbonation drops.

With what you say about time being a dependent...then shouldn't we be able to calculate for it? As you say, it isn't a straight forward calc because there is surface area at play as well, but that's not difficult to work into an equation. I'm just not skilled enough to work with Henry's Law or the Van 't Hoff equation.

 

[MHB]

Sadly there are so many variables, I'm sure you could get a number, just as sure that it might be random!
Mark

 

[duncbrewer]

There's no doubt it's complicated. But we all agree that given enough time equilibrium will be reached. Hence the value of trying to get this going during the end of ferment rather than after cold crash and pre packaging.
When you think of it 2.6 vols of CO2 is a lot out of a cylinder for a 20 litre batch. I get my CO2 free from the supplier but I still try and get the natural carbonation as the Germans have done for years.

 

[MHB]

2.6V is about 5.2g/L or 104g, I'm paying around $10/Kg for CO2 (would better if it was free) so that’s $1.04 per 20L batch.

A price I'm more than happy to pay for good consistent results. There are also some good reasons to vent most of the CO2 early in the ferment (strips out O2, removes some undesirable volatiles, lowers pressure on yeast reducing some types of flavour production...).
German brewers do it, true but they do it cold and in most cases they are drawing off the CO2 evolved during fermentation, purifying it, storing it under pressure (not necessarily as a liquid) then reusing it. If the Reinheitsgebot didn’t make them they probably wouldn’t even bother to do that.
I really do think you’re pushing it up hill, you will get better results keeping it simple, don’t pressure ferment Ales, remember the brewers using pressure fermentation are those making the worst commercial Lagers, not the best.
Mark

 

[duncbrewer]

Yes I start with no pressure and only add the spunding later. No doubt you squash yeast expression with pressure which is only useful for certain situations.

 

[Bark0s]

2.6V is about 5.2g/L or 104g, I'm paying around $10/Kg for CO2 (would better if it was free) so that’s $1.04 per 20L batch.

A price I'm more than happy to pay for good consistent results. There are also some good reasons to vent most of the CO2 early in the ferment (strips out O2, removes some undesirable volatiles, lowers pressure on yeast reducing some types of flavour production...).
German brewers do it, true but they do it cold and in most cases they are drawing off the CO2 evolved during fermentation, purifying it, storing it under pressure (not necessarily as a liquid) then reusing it. If the Reinheitsgebot didn’t make them they probably wouldn’t even bother to do that.
I really do think you’re pushing it up hill, you will get better results keeping it simple, don’t pressure ferment Ales, remember the brewers using pressure fermentation are those making the worst commercial Lagers, not the best.
Mark

Great points both Mark and Dunc.

I guess I was trying to expose to no oxygen but really I could just minimise oxygen exposure. I could ferment conventionally and add priming sugar late and then flush the headspace with CO2. Or do the same with dry hopping.

Next brew does need to go back to basics. I was having carbonated beer. Back to back batches without carbonation isn't fun.

Carb cap may get a work out.

 

[Bark0s]

I'm here to bump my own thread and say that what I thought might be possible is in fact possible, with the correct maths (well, understanding of various pressures at various temps). My most recent brew was a 'Ben's Lefty Juice NEIPA' that I pressure fermented. I also de-pressurised so I could dry hop. I know I know, I'm not meant to open the fermentor to add hops but I did anyway. Not once but twice! I burped with CO2 connected afterward, not perfect but better than not.

Anyway, I then bottled this at 22 psi. It has come out incredibly. All thanks go to grain and grape for their fwk but I'm also chuffed that I can, riskily, counter pressure bottle fill at room temps and maintain carbonation.

 

[MHB]

Must be cool at your place, what you are saying makes sense (mathematically) at close to 12oC and 150 kPa.
Be fun to see you try this in summer, the same 5.2g/L at 20oC needs around 215 kPa which is going to be very lively.
Mark

 

[duncbrewer]

@MHB
I think that at that pressure it would be lively at any temperature.

I did counterpressure fill my elderflower fizz into champagne bottles with the keg at 35 psi to get the vols I wanted (over 4 vols ). But that was at about 5 celsius.