Hot side aeration

Get advice on making beer from raw ingredients (malt, hops, water and yeast)
Post Reply
Under the Table
Posts: 1879
Joined: Mon Mar 22, 2010 7:10 pm
Location: Christchurch, Dorset

Hot side aeration

Post by guypettigrew » Mon Feb 18, 2019 9:39 pm

How do you guys avoid hot side aeration? My set up certainly doesn't.

My 3 vessel system uses a pump from the mash tun to the boiler.

The wort is pumped very slowly into the top of the boiler, using a small bore silicone tube. The tube is high up in the boiler so it allows me to see the rate at which the wort is going into the boiler. Allows me to aim for a sparge rate of about 1/2 litre a minute which gives me a good extract percentage.

But this also means the wort splashes into the boiler encouraging hot side aeration. Which I don't want!

So, how do you get your wort from MT to boiler without air potentially spoiling it?



User avatar
Even further under the Table
Posts: 2188
Joined: Fri Mar 13, 2009 1:18 am
Location: Sunderland.

Re: Hot side aeration

Post by Eric » Mon Feb 18, 2019 10:51 pm

I don't and for all those beers I brew, it helps. There are at least as many benefits as there are downsides.

It isn't one of those things that people fret over that don't exist or are impossible to avoid, but unless you are intent on making beer in a specific way to avoid oxygen at all costs, brew your beer and enjoy it as you always have.
Without patience, life becomes difficult and the sooner it's finished, the better.

User avatar
Under the Table
Posts: 1645
Joined: Thu Dec 29, 2005 1:00 pm
Location: Whitley Bay

Re: Hot side aeration

Post by bitter_dave » Tue Feb 19, 2019 6:59 am

I thought the consensus now was that hot side aeration wasn’t something to worry about, at least on a homebrew scale. These days I make no effort to avoid splashing when transferring from the mt to boiler, but i am happy to be advised differently if there are good reasons to avoid this

User avatar
Under the Table
Posts: 1262
Joined: Wed Dec 07, 2011 9:29 am
Location: France Gascony

Re: Hot side aeration

Post by IPA » Tue Feb 19, 2019 9:02 am

Aleman wrote:
Tue Feb 19, 2019 6:12 am
I brew in a 100% nitrogen atmosphere :P
Presumably it comes from diesel exhaust emmisions. =D>
"You're not drunk if you can lie on the floor without holding on." Dean Martin

1. Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in sideways, thoroughly used, totally worn out and loudly proclaiming... "f*ck, what a trip!"

Under the Table
Posts: 1879
Joined: Mon Mar 22, 2010 7:10 pm
Location: Christchurch, Dorset

Re: Hot side aeration

Post by guypettigrew » Tue Feb 19, 2019 9:46 am

Thanks all. Another thing not to worry about!


Steady Drinker
Posts: 71
Joined: Fri Jan 02, 2015 1:23 pm
Location: Penarth, South Wales

Re: Hot side aeration

Post by patwestlake » Wed Feb 20, 2019 2:01 pm

The Brulosophy experiment below might be woth a look; basically he whisked f#@k out of the wort at every stage vs a control where he was careful and there was no detectable difference (5 gal batch). I also seem to remember the wisdom being that its another one of those "maybe important" things in the long list that commercial brewers avoid as they don't want to lose 1000+ litres at a time. As noted earlier, I'm certainly not sure I could isolate HSA as a flaw in my beers vs all the other things I don't do quite right!!!!

From pt1 in link below

The results of this exBEERiment corroborate the findings from other experiments on the same topic. I exerted more effort aerating the mash and wort than I’ve ever exerted trying to limit hot-side aeration, and even so, there seemed to be absolutely no detriment to the quality of the finished beer. While I’ve touted the whole “HSA is myth” thing in the past, I’ll admit I was likely engaging in confirmation bias, simply seeking evidence to support my practices. However, the growing amount of evidence supports the notion that HSA, while perhaps not necessarily mythical, does not have a noticeable negative impact on homebrewed beer and hence can be appropriately relegated to the annals of homebrew history. ... t-results/ ... t-results/

FV : Weiss Weiss Baby! Weissbier
Conditioning (bottles) : Citra SmaSh, Kolsch, Dirty Harry (Ghost Ship), Galaxy Delight

Next : Patersbier, some sort of Goes, Cindy Juice

User avatar
So far gone I'm on the way back again!
Posts: 7686
Joined: Fri Mar 19, 2010 6:22 pm
Location: Derbyshire, UK

Re: Hot side aeration

Post by Kev888 » Wed Feb 20, 2019 3:41 pm

I generally caution against drawing 'too' much from Brulosophy, especially when they fail to find effects. It doesn't necessarily mean there are none to find, or that results will translate to different scenarios; however they can sometimes help to put a perspective on things. As probably in this case can systems like the Braumeister, which are in use by large numbers of people across the world making all sorts of different beers and which pour hot wort over and down the grain pipe throughout the mash; not really splashing, but certainly exposing a large amount of hot wort directly to air.

I wouldn't personally try to increase HSA, but don't have any great concerns about reducing it either, in my homebrewing. I've ample scope for other things to spend time and attention improving, much more beneficially.

Hollow Legs
Posts: 374
Joined: Tue Jun 05, 2018 9:19 am

Re: Hot side aeration

Post by Robwalkeragain » Wed Feb 20, 2019 8:03 pm

Kev888 wrote:
Wed Feb 20, 2019 3:41 pm
I generally caution against drawing 'too' much from Brulosophy, especially when they fail to find effects.
I’m sure Marshall himself would tell you nothing he does is conclusive too, after all, it’s one experiment. Good fun, interesting and good for myth busting, but certainly not all that scientific.

HSA i would say is more important if you’re brewing very pale beers rather than styles like pale ales. It’s mostly pursued by german breweries who want to brew very light coloured beers using only lager malts, but that said, it’s a good thing to avoid if you can.

With a system that brings in lots of oxygen - mash recirc, a decent “fall” on transferring to copper and a vigorous boil - i still manage pretty pale beers with extra pale malt, so for me at least, it’s not a concern.

User avatar
Under the Table
Posts: 1364
Joined: Wed Nov 28, 2012 6:24 pm

Re: Hot side aeration

Post by Hanglow » Fri Feb 22, 2019 9:53 pm

I think there is merit to at least looking into eliminating HSA, but it isn't necessary for a lot of beers that homebrewers brew imo. That said if you want to brew lagers and really hop forward modern american beers and be a technical brewer then it's well worth a look, there is a lot of good info on the likes of

I have tried a few of their processes on my homebrew over the last couple of years, one thing I noticed was the total elimination of the smell of mashing, which was a bit weird. The beers I made were very good, but weren't strictly low oxygen as I bottle
Planned: Green Hop ale
Fermenting: Nothing
Bottled: Home grown Halletau Mittelfruh golden ale, centennial golden ale, Brown Kolsch, Strong Burton with Brett C

Post Reply