Is oxidation during mash a real concern?

[b1v1r]

I am just getting back into brewing from extract and partials to all grain. I've always been very weary of preventing hot side oxidation after the boil. It seems there is some debates on this already and I don't want to get into that.

With all grain, the mash is an additional point to introduce aeration and potentially oxidation. What I am wondering is if this is really a concern during mashing. As I am doing recirculating mashes, I make sure I am not splashing, but there is always some air in the pump, hoses, etc. Additionally, I use an all-in-one that combines the mash tun and kettle where I have a colander that I pull up to drain and there may be some aeration as the wort falls back into the kettle.

It seems that it should not matter too much pre-boil to me. My thoughts here are that the boil will degas anyhow, removing the oxygen, and unless the oxidation damage is already done prior to the boil it just may not matter so much.

Anyone do any experimenting on this topic? Anyone have personal experience with oxidation during the mash causing issues?

Cheers!

 

[castillo556]

I wouldn't see why it would matter, it's all going to be released during the boil.

Then you are going to re-oxygenate it before you pitch your yeast.

 

[chickypad]

Brulosopher did an experiment on HSA. I'm in the don't worry about it camp.

 

[brewkinger]

Brulosopher did an experiment on HSA. I'm in the don't worry about it camp.

This ^^^
Any dissolved gas will be driven off during the boil.

 

[b1v1r]

Thanks all for the confirmation. I remain in the don't worry about it camp. Cheers!

 

[andrewf1985]

+ 2 on the link. My sparge runnings drop the height of my kettle + ive never had any issue or tasted any when i tried it with tubing.

Dont fear the HSA

 

[ArkotRamathorn]

Parroting the past posts. Pre-boil aeration? Don't worry about it. The boil drives of anything that could maybe have formed.

Post boil, I've done several whirlpools for IPAs that I have started chilling and they were still around 180-190f and gave it some very vigorous stirring that should've definitely oxygenated a little and had no problems. I would almost bet money to go really obvious HSA off flavors you'd have to drop a sintered stone with pure oxygen pumping into your wort right when you do flame out. Not that you should just pour your beer straight after flame out into your fermenter without chilling of course.

 

[didinho]

Anyone have personal experience with oxidation during the mash causing issues?

no. never heard about mash oxidation. also people that do stirred mash never worry about it.

 

[SpeedYellow]

I wouldn't be so quick to dismiss this. There's a lot of chemistry going on in the mash tun, so I'm not so sure O2 would be considered totally inert there. Charlie Bamforth was on either Basic Brewing or Beersmith podcast a couple years ago and touched on this. I forget his conclusions offhand, but it did seem like preboiling your mash water may be a good idea.

 

[ArkotRamathorn]

I wouldn't be so quick to dismiss this. There's a lot of chemistry going on in the mash tun, so I'm not so sure O2 would be considered totally inert there. Charlie Bamforth was on either Basic Brewing or Beersmith podcast a couple years ago and touched on this. I forget his conclusions offhand, but it did seem like preboiling your mash water may be a good idea.

In theory that may be the case that pre-boiling could be a good idea.

In practice though, most of us wouldn't want to add another 20-30 minutes of boiling, then cooling the water to our desired strike temps (I shudder to think how much longer my decoction mashes would be when I mash in at 120-130F waiting for boiling water to chill that much).

 

[chickypad]

Charlie Bamforth was on either Basic Brewing or Beersmith podcast a couple years ago and touched on this. I forget his conclusions offhand, but it did seem like preboiling your mash water may be a good idea.

I'll have to listen to it again by my take was it has a minimal impact compared to post fermentation oxidation. I don't remember anything about preboiling mash water.

 

[paperairplane]

I don't believe in hot side aeration. At least not at the home brew level. I certainly don't worry about it pre boil.

 

[SpeedYellow]

In theory that may be the case that pre-boiling could be a good idea.



In practice though, most of us wouldn't want to add another 20-30 minutes of boiling, then cooling the water to our desired strike temps (I shudder to think how much longer my decoction mashes would be when I mash in at 120-130F waiting for boiling water to chill that much).

All that is true, but convenience is beside the point. Virtually ALL brewing activities I'd rather not do, but do anyway for the sake of beer quality.

I can't help but note the irony that you're concerned about time yet do decoction mashes, the ultimate time waster!

 

[soccerdad]

In general I follow a simple guideline:
- oxygen on brew day in no prob and can be good (even hot side aeration is not a big deal for homebrewers, but who oxygenates hot wort anyway? we oxygenate cooled wort)
- avoid oxygen after fermentation has begun

 

[kh54s10]

All who do batch sparging stir the mash very aggressively, then vorlauf and drain, add sparge water and stir it very well again, vorlauf and drain again. This has to be adding lots of oxygen yet the beers brewed with this method are as good as any other method......

IMO, hot side aeration is of no concern in homebrewing at any stage of the process.

 

[ArkotRamathorn]

All that is true, but convenience is beside the point. Virtually ALL brewing activities I'd rather not do, but do anyway for the sake of beer quality.

I can't help but note the irony that you're concerned about time yet do decoction mashes, the ultimate time waster!

I can see the irony . I guess to me the worst part of brewing is right up until I'm mashed in. The longer I have to wait to get mashed in the more I feel like the brew day is taking too long. Decoctions are time consuming but I enjoy the process. Once I'm mashed in I know I can sit down, crack a beer and relax for 30-40 minutes before I feel the need to go start pre-cleaning stuff so I dont have to do it later. I don't deliberately aerate my mash, but then again I don't really put any effort into preventing it and havent noticed any off-qualities in my beer that couldn't be explained by other more obvious issues (recipe/yeast health/fermentation temps).

I could definitely see the argument for head retention considering some of the things I've listened to of Dr. Bamforth's. Any time you see some foam/bubbles form thats the only time that particular bubble/foam with form, so you start getting a ton of frothing before the boil you could be destroying "foam positive" proteins potentially affecting your head retention. I think though you'd have to really go to town on the mash with a whisk attached to a drill, or pumping pure oxygen through a manifold up into the mash to really see an appreciable drop in head retention qualities or to notice the potential flavor impacts. (commercial breweries have it nice since they always have 190F water on hand so when they mash in their water already has very low dissolves oxygen levels so its a classic "works great for commercial breweries due to size but at the homebrew level would not be feasible without cost prohibitive equipment or use of time")

 

[Denny]

I am just getting back into brewing from extract and partials to all grain. I've always been very weary of preventing hot side oxidation after the boil. It seems there is some debates on this already and I don't want to get into that.

With all grain, the mash is an additional point to introduce aeration and potentially oxidation. What I am wondering is if this is really a concern during mashing. As I am doing recirculating mashes, I make sure I am not splashing, but there is always some air in the pump, hoses, etc. Additionally, I use an all-in-one that combines the mash tun and kettle where I have a colander that I pull up to drain and there may be some aeration as the wort falls back into the kettle.

It seems that it should not matter too much pre-boil to me. My thoughts here are that the boil will degas anyhow, removing the oxygen, and unless the oxidation damage is already done prior to the boil it just may not matter so much.

Anyone do any experimenting on this topic? Anyone have personal experience with oxidation during the mash causing issues?

Cheers!

I have experimented with additives supposed to reduce mash oxidation. They made no difference to the finished beer. That leads me to conclude that mash oxidation is not an issue in the first place.

 

[Denny]

All who do batch sparging stir the mash very aggressively, then vorlauf and drain, add sparge water and stir it very well again, vorlauf and drain again. This has to be adding lots of oxygen yet the beers brewed with this method are as good as any other method......

IMO, hot side aeration is of no concern in homebrewing at any stage of the process.

In batch sparging, you should stir thoroughly but not aggressively.

 

[cannman]

Not a concern. Another reason to have a healthy yeast starter so they can take care of that for you!

 

[kh54s10]

In batch sparging, you should stir thoroughly but not aggressively.

I have aggression issues, I guess. If the mash does not cooperate I bash it with my mash paddle!

 

[Denny]

I have aggression issues, I guess. If the mash does not cooperate I bash it with my mash paddle!

Talk to it...swear at it...but don't abuse it!

 

[Homercidal]

IIRC Bamforth's suggestion was to not worry about HSA because even though it may *technically* be doing something, it's affect on the beer is minuscule when compared to all of the things you SHOULD be worrying about post-fermentation.

Almost anything you could do to impart oxygen after the fermentation is going to degrade the beer much faster and to a higher degree than anything you could do pre-fermentation.

So put your effort into gentle racking and careful packaging.

 

[SpeedYellow]

Yes, I just re-listened to Bamforth (Beersmith "Flavor Stability" podcast #74) and he:

1) Scoffed at the idea of hot side aeration.
2) Said that using de-aerated water or nitrogen-purging the grist are "overkill".

Like Homercidal wrote above, it's all about post-fermentation: (a) minimize O2 uptake and (2) keep the beer chilled.

 

[cannman]

Dr. Bamforth is like a beer God