Oxygen Question

[Laurin]

Hi
I read now a couple of times that when you bottle you should splash as little as possible to ensure that no oxygen goes into the brew, because it triggers off flavours. Why is it that you are supposed to aerate the wort then before you let it ferment the first time?

I mainly brew non beer drinks, but I want to at some point if I have the space/equipment. Does this "no-splash" rule also apply to cider, wine etc?

Thanks for any help.

 

[adomant]

Good question. Yeast needs oxygen to multiply which is important at the start of fermentation. Beyond this, oxygenation is a bad thing as it will cause the beer to go stale quicker, leading to a wet cardboard off taste in bad examples.

 

[Aleman]

Aerating the wort prior to fermentation is not a problem as the wort contains no alcohol . . . plus an actively fermenting wort uses oxygen up at a frightening rate.

After fermentation the Beer contains alcohol and in the presence of oxygen this oxidises first to acetone and then to Acetaldehyde (Green apples apparently . . . I'm not convinced) personally I think you get a sherry like aroma and taste.

So the mantra goes "Before Adding Yeast, Oxygen Good! . . . . After Adding Yeast, Oxygen Bad!"

 

[Laurin]

Thanks for the help.

 

[Pinck]

One of the most popular beginner homebrewing authors John Palmer often talks about something called "hot side aeration" which is supposed to have a staling effect on the finished beer from excess oxygen introduced during the brewing process while the wort is still hot. As a result, thousands of brewers fear this tragic effect (that they've never tasted) and avoid pouring hot wort from one vessel to the next.

More recent research shows that this is more of a myth than an actual concern though. Healthy fermentation should have no issues dealing with compounds that are created from hot wort being exposed to air. And on the bright side, unhealthy fermentation will cause far greater issues that will mask the staling effect :)

 

[DaryllLand]

The ‘hot side’ thing is something I’ve never thought about when trying to avoid oxygen as the boil would always kills any bacteria in my mind (flavours might still remain though, no?).

My query is this, once I have cooled my wort down to fermentation temperaturea I often pour it from the tap on my HLT into the FV from a height which creates splashing and bubbles (oxygen).

Once this is complete, this is when I introduce my yeast. Is this okay or should I be transferring the wort as smoothly as possible into the FV, pitching the yeast, putting the lid on and then shaking it to oxygenate the wort?

Help/advice is always much appreciated!

Cheers

 

[MickDundee]

The ‘hot side’ thing is something I’ve never thought about when trying to avoid oxygen as the boil would always kills any bacteria in my mind (flavours might still remain though, no?).

My query is this, once I have cooled my wort down to fermentation temperaturea I often pour it from the tap on my HLT into the FV from a height which creates splashing and bubbles (oxygen).

Once this is complete, this is when I introduce my yeast. Is this okay or should I be transferring the wort as smoothly as possible into the FV, pitching the yeast, putting the lid on and then shaking it to oxygenate the wort?

Help/advice is always much appreciated!

Cheers

The key word here is “hot”. If you’ve already cooled your wort as you say then hit side aeration shouldn’t be a problem.

 

[DaryllLand]

The key word here is “hot”. If you’ve already cooled your wort as you say then hit side aeration shouldn’t be a problem.

I think there's a misunderstanding here Mick. I just wanted to know thoughts on 'Oxygenating before pitching yeast' or 'Pitching Yeast, closing the FV then Oxygenating'.

Hope that's a little clearer.

Cheers.

 

[Madhouse]

Aeration of the wort helps the yeast out - they need it to do their thing.
After that oxygen is bad due to its impact on the alcohol.

I’d say this would therefore apply to cider and wine also as neither of the above statements are specific to beer.

 

[stevey]

You wouldn't want to be shaking a full fermenter even if you were strong enough, the lid will definitely come off.

 

[Nicks90]

I was always told to beat your wort like it owes you money, just before adding the yeast to ensure it is fully oxygenated.
Then seal it up and don't let any more oxygen get to it.

As for hot aeration, never heard of it. Hope it's a myth, as all my ag brews have involved me letting the wort cool to 80c and then opening the tap on my boiler and letting it pour in to my fv 3 foot below....

 

[chthon]

I was always told to beat your wort like it owes you money, just before adding the yeast to ensure it is fully oxygenated.
Then seal it up and don't let any more oxygen get to it.

As for hot aeration, never heard of it. Hope it's a myth, as all my ag brews have involved me letting the wort cool to 80c and then opening the tap on my boiler and letting it pour in to my fv 3 foot below....

It's interesting to know the effect long term. Brülosophy did the test with excess hot side aeration, but their beers tend to be drunk in less than two months.

I actually made several beers where I could have had hot-side aeration, I just tend to be calm when moving the hot mash for filtering. I also made several beers using decoction. As an experiment, I always try to keep one bottle for a year. I must say that I mostly have never had off-tastes after a year, except my doppelbock.

 

[Nicks90]

but their beers tend to be drunk in less than two months.

Mine are lucky to last 2 weeks!

 

[terrym]

I was always told to beat your wort like it owes you money, just before adding the yeast to ensure it is fully oxygenated.

If you have boiled the water before you make up your brew (as in AG) then thats what's needed, cos you have boiled out most, if not all, of the dissolved gases.
But if you have made up a kit using mostly cold tap water it probably isn't because tap water is probably O2 saturated.
Either way oxygen isn't very soluble in aqueous solutions (unlike CO2) so there is only a certain amount of beating you can do after which you are wasting your time and effort