Hot Side Aeration Rumbles on

[Leann ull]

This came into my Twitter account this morning
http://immaculatebrewery.com/oxygen-and-mashing/

It makes an interesting read and concludes for Homebrewers if it ain't broke.

[Pheeel]

I've stopped caring about it. After seeing how much breweries agitate I'm not concerned!

[molc]

Hehe, I make enough trouble for myself already - I don't need to go looking for more!

[DEMPSEY]

Alot of reading there but the case for or against is not proven for me. For those that want the case explained HSA claims that by allowing the hot wort splash into your boil kettle it absorbs oxygen and this causes the final beer to have a shorter shelf life. Many commercial brewery's have being doing this for years and have not changed the practice. Whether you believe it's true or not as home brewers we can adopt a simple remedy of not allowing the wort to splash about as we transfer to our boil kettles. So when the case is finally proven or unproven you can sit back and say, I played it safe

[Will_D]

  Solubility of oxygen in water is inversley proportional to temperature 

[oblivious]

Solubility of oxygen in water is inversley proportional to temperature 

Good old Mr Boyle

[DEMPSEY]

Coming back to this one . Being reading around the web and low dissolved oxygen. The statement is,
"you cannot make a proper Helles without employing a low oxygen brewing process".
The commercial German Brewery's as well as other Brewery's employ in their process methods of reducing as much as possible any oxygen being in their Brewday operation.All brewing water
is degassed as a standard part of water treatment, and delivery pipes for malt are purged with steam or inert gases, such as nitrogen.
The grist is milled in-line with the delivery pipe under a blanket of inert gas.
vibrating mash agitation systems such as the Shakesbeer device produced by Krones can aid in knocking dissolved oxygen out of solution.

[DEMPSEY]

This method would be beyond Homebrewer's ability to control but we can adapt a system to help, It requires that you pre-boil all of your
mash water immediately before use, quickly force chill it to strike temperature,
add a modest dose of sodium metabisulfite (SMB), and completely eliminate all
sources of splashing or aeration (such as leaky pump lines).
The SMB will act as a chemical oxygen scavenger and protect the mash from oxidation throughout
the hot side of the process. Over the course of the boil and fermentation.

[pob]

Dr Charlie Bamforth probably sums it up best in how (ir)relevant HSA is within the brewing process; addresses the "The chemistry suggests there could be a flavor improvement but that still seems objectively inconclusive" bit.

Flavor Stability in Beer with Dr Charlie Bamforth – BeerSmith Podcast #74

From 22'30" to 26'00" ish, great overall podcast to listen to anyway - basically he concludes that it is totally meaningless unless you have premium end packaging & perfect storage for your beer to begin with.

The issue of it rumbling on as a concern is also mooted at 25'20" regarding what yeast does with it anyway.

QED or arse, as I say

[DEMPSEY]

Back again to this vexing issue.Was reading about this (again) as its like an itch that wont go away. John Kimmich,brewer of Heady Topper believes it exists. start at 34 minutes.

[Qs]

At homebrew batch sizes though?

[giacomo]

Have we disproved the related xbmt? And explained why it doesnt prove HSA is not an issue?

http://brulosophy.com/2014/11/18/is-hot-side-aeration-fact-or-fiction-exbeeriment-results/

[DEMPSEY]

Yes looked at that again and all the rest and although when they say the main issue is in the packaging process they do say as well that splashing hot wort around is probably best to avoid . But not to fret

[Leann ull]

#fakenews

[Dr Jacoby]

The low oxygen brewing approach is different to what most people understand hot side aeration to be. Hot side aeration  is usually taken to refer to oxidation that shows itself in shorter shelf life. But the low oxygen approach is more radical. It suggests oxidation occurs when any oxygen interacts with malt from the moment it's milled.  The main negative effect is a dulling of fresh malt flavours.

The main evidence for this comes from research conducted in the 80s by German breweries  (particularly Weihenstephan). It led to large German lager breweries investing in low oxygen brewhouses, so they obviously took the research very seriously.

I reckon there might well be something to it (the delicate malt flavours in top quality German lagers are rarely matched in breweries anywhere else in my experience). Then again, Pilsner Urquell is aged in barrels, so there are examples out there of world class lagers that don't stick to the same rigorous  low oxygen approach (though perhaps Urquell do on the hot side?).