Water deaeration / High Gravity Brewing

[Surly_goat]

I'm making my first attempt at doing some high gravity brewing. I made a double batch of my pale ale and threw it into the fermenter at an OG of 1.101 and 80 IBUs. Though mechanically my hop spider was too full so I need to.change the hopping process as I guarantee my utilization was much lower than 90%.

Once the fermentation is complete I plan to keg it at 1/1 deaerated water with beer. I'm not feeling super confident about how to deaerate the water. The engineers tool box says it holds no dissolved oxygen at 100c and I'm at near sea level so that should be good. But all the technical information talks about co2 scrubbing as well. Should I put in a keg at high PSI and shake it? Is the second step needed?

 

[eric19312]

I've never done this but have thought about it. I suspect this is primary use of dearated water in commercial breweries not for avoiding DO water in mash.

In my thought experiment I'd boil give the water a decent boil maybe at least 15 minutes and then transfer it while still boiling through a plate chiller into a well purged keg. Really don't see why this couldn't be the serving keg, either before or after the beer has been added via closed transfer. So long as the beer is still boiling when it hits the plate chiller it should not have opportunity to pick up any O2 on way to the keg.

 

[mongoose33]

The LODO people deoxygenate water going into the mash using one of two methods: a method using yeast to scavenge the O2, or boiling. I boil.

The process as recommended is to boil the water for at least 5 minutes to deoxygenate it. What I do then is quickly chill it to strike temp (around 160-162 depending on conditions), and then underlet the mash with it.

To minimize diffusion of atmospheric oxygen into the now-boiled water, you can add a cap to the water. I use the lid from a smaller kettle which you see in this pic showing its use as a lauter cap. It's not perfect but it reduces the surface exposed to air by probably 85-90 percent.



If it were me trying to do what you want to do, I'd boil, drop to some temp reasonably close to the fermented beer, and right in it goes. One advantage to a system recirculating using a pump is you can recirc the boiling water which sanitizes everything. While there may be a little O2 that would diffuse back in, if you do it fast you'll minimize that.

Another way might be to pour the boiling water into a vessel you can seal. Hit it with a lot of pressurized CO2 to make up for the vacuum which will form when it cools, then transfer the cooled water to the fermenter.

 

[Surly_goat]

I was going to boil for 5 minutes, recirculte through my chiller and back in to sanitize, then pour into co2 purged keg from chiller while it's on my grain scale to measure out exactly the half keg.

The beer then will be used to top up the keg from the fermentor. Kinda like the idea of just running the still boiling water into keg and then just sealing it with 30 psi. Would have to wait a day to add beer though obviously. I imagine that would create the lowest possible oxygen pickup I can create.

Does anyone know anything about the co2 scrubbing?

 

[RPh_Guy]

Does anyone know anything about the co2 scrubbing?

Adding CO2 doesn't remove O2.
Otherwise carbonated beer would never oxidize

 

[ajdelange]

He's talking about sparging with CO2 - not just pressurizing with it. The partial pressure of O2 within a CO2 bubble is lower than it is in the beer so O2 will migrate to the bubble - at least that's the theory and obviously once the partial pressure inside the bubble is the same as in the beer no further migration will take place. I think the real value of transferring against CO2 back pressure is that the water is not subject to atmoshpheric O2.

Seems to me that adding a pinch of metabite after all this is probably a good idea.

 

[RPh_Guy]

Doh! Thanks.

 

[Surly_goat]

Whats the metabite?

I have a note here from the home brewers meetup the other night that Sulfate would chemically bond with and precipitate oxygen..... Why i would write just sulfate I'm not entirely sure.

 

[ajdelange]

Metabite is sodium metabisulfite Na2S2O5. Add it to water and you get Na2S2O5 + H2O = 2Na+ + 2SO3-- + 2H+. The SO3-- ion is a reducing agent: 2SO3-- + O2 --> 2SO4--. Thus metabite, sometimes though of as solid sulfur dioxide (you can smell it as soon as you metabite to water) produces sulfite ion which is oxidized to sulfate ion by any oxygen which is present. Oxygen is not precipitated. It stays in solution as part of the sulfate ion.

 

[sixhotdogneck]

Metabite is sodium metabisulfite Na2S2O5. Add it to water and you get Na2S2O5 + H2O = 2Na+ + 2SO3-- + 2H+. The SO3-- ion is a reducing agent: 2SO3-- + O2 --> 2SO4--. Thus metabite, sometimes though of as solid sulfur dioxide (you can smell it as soon as you metabite to water) produces sulfite ion which is oxidized to sulfate ion by any oxygen which is present. Oxygen is not precipitated. It stays in solution as part of the sulfate ion.

Precipitation is normally H2O. For some reason I found that humorous, thinking about a reaction that would in fact precipitate oxygen and hoping it doesn't occur in our atmosphere.

 

[RPh_Guy]

Precipitation is normally H2O. For some reason I found that humorous, thinking about a reaction that would in fact precipitate oxygen and hoping it doesn't occur in our atmosphere.

Not precipitate, but I transform atmospheric oxygen into mostly carbon dioxide. Lots of it, every single day