Harsh hop bitterness

[manticle]

I wish I had a lathe. Men have lathes.

Soon I hope to buy a lathe for my workplace so I can make sexy things from aluminium and stainless.

 

[quadbox]

I was looking for molar solubility graphs, but close enough for internet handwaving points regardless. The solubility of oxygen at 0C (crash chilling temps) is still utterly miserable compared to co2. Will 0.07grams of oxygen per kilogram of beer oxidise more than 0.04 grams? Hell yes. Will that be measurable compared to other factors involved at the early stages of conditioning? Lol.

The entire "CO2 blanket protects your beer" thing has been debunked very thoroughly, very often, but wow does it forever rise from the grave.

 

[manticle]

I sleep with a co2 blanket.

 

[Danscraftbeer]

That graph reassures my suspicions. I'll advocate for no exposures of your beer is best. I'll go the hop stands instead of throwing dry pellets or flowers into a post ferment beer.

 

[Matplat]

Please elaborate.... I haven't heard of this debunking previously?

Seems plausible enough to me that in the same way salad dressing separates in the jar, an undisturbed atmosphere in the top of your FV will do the same thing with CO2 and any remaining air?

Isn't that what allows open top fermentation vessels to work?

 

[manticle]

My understanding is that co2 offers protection while it's being produced during fermentation (some - it's not a mylar or cryovac barrier). However once fermentation slows or stops, your blanket gets thinner every second.

Some brewers seem to think they could have house guests sleep under it for half a year.

 

[Danscraftbeer]

Yeah. Then when your beer cools it absorbs that Co2 layer. Then it probably absorbs your used fridge air if its not air tight.

Edit: my notes; A standard 30lt plastic fermenter with a 20lt brew. Cold chilling will draw in a basket ball worth of volume of air.
Cant rely on a Co2 layer there.

 

[mckenry]

Put simply if CO2 and air didn't mix, we'd all be dead. The 'protective layer' would be on earth and the air would be above that.

 

[GalBrew]

You need to keep in mind gas partial pressures when the magical co2 blanket is discussed.

 

[Zorco]

Put simply if CO2 and air didn't mix, we'd all be dead. The 'protective layer' would be on earth and the air would be above that.

I thought about this but realised that the sun's energy leads to atmospheric turbulence and therefore mixing of the gases.

Not the same for the fermenter. There must be a property of dissimilar gases to homogenise. Is it just entropy? Is the rate of diffusion less than the natural mixing due to the high temperature (yes, I mean 0C) of the gases?

 

[MastersBrewery]

I sleep with a co2 blanket.

I would but SWMBO gets a lil jealous.

I have really only noticed harshness from an APA when ferm temps went nuts on me.(when I first move I wasn't setup but was hangin for a brew. I should have waited it ended up on the lawn) Or when underpitched, yeah I have thrown handfuls of hops at brews but I find time has always allowed them to settle and mellow some.

 

[Frothy1]

Yeah. Then when your beer cools it absorbs that Co2 layer. Then it probably absorbs your used fridge air if its not air tight.

Edit: my notes; A standard 30lt plastic fermenter with a 20lt brew. Cold chilling will draw in a basket ball worth of volume of air.
Cant rely on a Co2 layer there.

Are we way OT?


When I move the FV from the fridge to the bench to keg, i see air lock activity (air going into the vat) in the small amount of time to get my **** together, maybe a minute or so.

I have never seen air lock activity when cold crashing, yes I'm always looking in the fridge.

 

[TheWiggman]

Yeah. Then when your beer cools it absorbs that Co2 layer. Then it probably absorbs your used fridge air if its not air tight.

Edit: my notes; A standard 30lt plastic fermenter with a 20lt brew. Cold chilling will draw in a basket ball worth of volume of air.
Cant rely on a Co2 layer there.

I'm not sure if you've made a typo but that's not even close. The difference is about 7% from 18°C to freezing. For 10l of dead space, that's 70ml of air drawn in which is 20% oxygen. Thus half a shot of oxygen will enter the space which will make stuff al difference if the liquid is kept cool and not agitated for a short period of time. I'd love to see some knowledgeable evidence behind the gas layers concept because I'm not convinced the different constituents simply separate themselves out in a still environment.

I've buggered up beer with poor yeast management, temps, infections, bad malt choices, too much hops, hop addition timing, storage, cleanliness and many other ways but I've yet to over-oxidise a beer by crash chilling it (and 100% confident I never will).

 

[Coodgee]

I'm not sure if you've made a typo but that's not even close. The difference is about 7% from 18°C to freezing. For 10l of dead space, that's 70ml of air drawn in which is 20% oxygen. Thus half a shot of oxygen will enter the space which will make stuff al difference if the liquid is kept cool and not agitated for a short period of time. I'd love to see some knowledgeable evidence behind the gas layers concept because I'm not convinced the different constituents simply separate themselves out in a still environment.

I've buggered up beer with poor yeast management, temps, infections, bad malt choices, too much hops, hop addition timing, storage, cleanliness and many other ways but I've yet to over-oxidise a beer by crash chilling it (and 100% confident I never will).

completely agree with the sentiments here but 10L of deadspace would be 10,000ml, 7% of which would be 700ml - so 5 shots of oxygen.

 

[MHB]

CO2 is used in fire extinguishers as it will displace O2, you can suffocate in a high CO2 environment...
When there is plenty of CO2 it will temporally displace all the other atmosphere, this includes on top of the beer in a fermenter, in the fridge; I think it gives good O2 protection while there is plenty being evolved.
It doesn't last, it slowly dissipates and blends into the air, then you have no protection at all.

if a 1.050 beer fermented to 1.010 40 points of gravity apparent attenuation or 10oP, 8.2oP real attenuation.
in a 23L ferment 1.886kg of sugars fermented gives 883g of CO2 MW is about 44g/M call it 20 moles at 22.4L/M , just under 450L of CO2
So we are talking fairly significant amounts being evolved during a brew.
Mark

 

[MastersBrewery]

CO2 is used in fire extinguishers as it will displace O2, you can suffocate in a high CO2 environment...
When there is plenty of CO2 it will temporally displace all the other atmosphere, this includes on top of the beer in a fermenter, in the fridge; I think it gives good O2 protection while there is plenty being evolved.
It doesn't last, it slowly dissipates and blends into the air, then you have no protection at all.

if a 1.050 beer fermented to 1.010 40 points of gravity apparent attenuation or 10oP, 8.2oP real attenuation.
in a 23L ferment 1.886kg of sugars fermented gives 883g of CO2 MW is about 44g/M call it 20 moles at 22.4L/M , just under 450L of CO2
So we are talking fairly significant amounts being evolved during a brew.
Mark

So as most of the ferment is done in the first 3 days, in the example above your brew is outputing 5L an hour on average.

 

[Zorco]

Brownish Motion. This seems to be appropriate to my last post

(Wish I didn't just focus on electrical)

http://www.physbot.co.uk/gas-laws.html

As MHB points out, the CO2 protection is best while it is continuously being evolved.

Cold crashing will increase the density of the CO2 and to equalise pressure, air ingress will occur ( through the airlock).

The gases will mix, through a combination of the turbulence of the air pulsing through the airlock as well as the natural motion of the particles.

From the posts above, that amount (20% O2) will not oxidase to any significant degree.

Back to my failed batch, it was almost an open ferment by using a pot. There was no sanitiser to prevent the ingress of acetobacter. And entropy would have mixed the air and acetobacter will have accessed my beer.

Any corrective additions?

Edit: stated as my first conclusion, not as an authority.

 

[GalBrew]

The gases will mix due to their partial pressures.

 

[Danscraftbeer]

I'm not sure if you've made a typo but that's not even close. The difference is about 7% from 18°C to freezing. For 10l of dead space, that's 70ml of air drawn in which is 20% oxygen. Thus half a shot of oxygen will enter the space which will make stuff al difference if the liquid is kept cool and not agitated for a short period of time. I'd love to see some knowledgeable evidence behind the gas layers concept because I'm not convinced the different constituents simply separate themselves out in a still environment.

I've buggered up beer with poor yeast management, temps, infections, bad malt choices, too much hops, hop addition timing, storage, cleanliness and many other ways but I've yet to over-oxidise a beer by crash chilling it (and 100% confident I never will).

I made the basket ball volume reference simple by seeing just how much the walls of a 30lt plastic fermenter will contract when its air tight from 18c to say 2c. I say for anyone to try it and see just how much it contracts. Its about the volume of a basketball. I wish I took a photo for reference now. Far from an expert and bordering on paranoia of contaminating beer but the way I see it if the fermenter is not air tight then that volume will be replaced by fridge air.
Anyhow Its enough to influence me into a kegmenter and co2 transfers etc. I don't have to worry about any of this anymore. B)

 

[GalBrew]

I made the basket ball volume reference simple by seeing just how much the walls of a 30lt plastic fermenter will contract when its air tight from 18c to say 2c. I say for anyone to try it and see just how much it contracts. Its about the volume of a basketball. I wish I took a photo for reference now. Far from an expert and bordering on paranoia of contaminating beer but the way I see it if the fermenter is not air tight then that volume will be replaced by fridge air.
Anyhow Its enough to influence me into a kegmenter and co2 transfers etc. I don't have to worry about any of this anymore. B)

I use a sterilock for cold crashing, so contamination isn't an issue. I've not noticed any oxidation in my beers early on from the air introduced into the fermenter during cold crashing (doesn't mean it doesn't happen though).

 

[rockeye84]

Been down this road. My bet would be on boil ph. You could try bumping your hop utilisation in your brew software up 10% as well, I run my hop utilisation in beer smith 2 @ 120%.