Cheapskate

[chthon]

I would have thought any oxygen introduce during mashig would have been boiled out during the boil?

Hm, perhaps a little bit. But the mash is rather hot, and this will speed up oxidation at boundary between air and wort in the mash. It is a simple precaution.

Actually, I would rather have a lauter manifold so I can skip this step, but I haven't the patience or the inclination to do that, so currently I scoop the mash from my mash tun into my bucket based lauter tun.

 

[northof49]

I would have thought any oxygen introduce during mashig would have been boiled out during the boil?

The solubility of a gas in a liquid at its boiling point is zero, and so I can say that any oxygen introduced on the hot side would be expelled by the boil (provided there is sufficient time to out gas). A separate question would be, does any oxygen introduced on the hots side cause any off flavours before the boil? The Brulosophy folks' results suggest that the answer to that is no (http://brulosophy.com/2014/11/18/is-hot-side-aeration-fact-or-fiction-exbeeriment-results/).

 

[MyQul]

Hi MyQul
... do you base that comment on having done the background research on hot side aeration that you promised to do over there (link) and concluding that it doesn't exist? Or have you forgotten what you found at the time?

{Later Edit: Sorry, I just thought it was funny how I was going to suggest you have a read up around hot side aeration (HSA), and searched the forum to see if it had been discussed on here before, and one of the first links in the search results was a post where you were saying you were going to go and find out about it ... now that I'm back where I have the links to some information ... most searches around HSA, and whether or not it "exists" (ultimately) lead back to Charlie Bamforth and the Jamil Zainasheff and John Palmer "Brew Strong" podcast where they interview him about it ... you can listen to the podcast there (link) and/or there's a set of notes (almost a transcript) there (link) }

Cheers, PhilB

The dog ate my homework :tinhat:

 

[PhilBrew]

Hi northof49

The Brulosophy folks' results suggest that the answer to that is no (http://brulosophy.com/2014/11/18/is-hot-side-aeration-fact-or-fiction-exbeeriment-results/).

... hmmm, but they do "own up" that their experiments were intended to find those results ...

... I’ll admit I was likely engaging in confirmation bias, simply seeking evidence to support my practices ...

and when you consider what the "experiment" was supposed to be investigating (i.e. the impact on beer staling, of HSA ... staling being a thing that happens over time) do you suppose that evaluating the results "after sitting in kegs in my keezer for about a week" would ever have been likely to find that out?

Still, they only generate the ......... ... you posted the link to it, and I was dumb enough to follow it

Cheers, PhilB

 

[the_quick]

Hold a second. But we are told time and time again, we need to oxidise wort before adding yeast for them to work. So oxygen during mashing, boiling and whenever before fermentation starts shouldn't mater surely??
Only after fermentation is finished.

 

[PhilBrew]

Hi the_quick

So oxygen during mashing, boiling and whenever before fermentation starts shouldn't mater surely??

... hmmm, but it's not just as simple as dissolved oxygen, introducing oxygen when the wort is hot encourages the production of compounds containing oxygen (from which it's not so easy for the yeast to access) ... as Bamforth explained in the interview I linked to above (copied from the points labelled 23-26 mins in the notes/transcription, also linked to) ...

In terms of flavor change, it's more than just oxygen, but the oxidative state of the wort/beer that is important. It is Redox reactions, and an oxidizing system/environment can transfer that oxidative power. Oxidizing a polyphenol could conceivably pass on the oxidative power to something else later. Redox potential is what to consider, even though oxygen is the main thing we think of. Oxygen itself is not "desperately reactive" and often needs to be activated
first (that is, given a mechanism) to do its damage. One is via enzymes; the other is via active forms called free radicals, which is where metal ions like iron and copper come in and promote the formation of radicals.
Superoxide, peroxide, hydroxyl (the most reactive) are the free radicals which are the real oxidative culprits.

... I've seen as many people, on forums around the internet, citing that interview with Bamforth as "proof" that HSA doesn't exist, as other people citing it as "proof" that it does (but there's other/more important things to worry about) ... so, if you feel this is something you want to have an opinion about, I really do recommend you spend the time listening/reading and deciding what you believe, personally

Cheers, PhilB

 

[the_quick]

It is becoming more and more complicated I'm out, just brew simple beers and most of them I'm happy with. I bet lots of micro breweries don't even think about it, I know quite well 2 that don't and they produce really good beer.
I guess we can make it as complicated as we want.
Anyway thanks @PhilBrew for that

 

[PhilBrew]

I guess we can make it as complicated as we want.

... indeed as complicated or as simple as we want ... which is why I added that "if you feel this is something you want to have an opinion about" to my suggestion that you go listen to that podcast. If you don't feel you need that level of detail in your life, then I think the "take-away messages" from all of that detail would be (copied from the point labelled 49 mins in the notes/transcription, of the interview I linked to) ...

At an MBAA meeting in Milwaukee, Bamforth gave a talk where they expected great things, but what he said was this:

(1) Consider using SO2;
(2) Keep oxygen exposure as low as reasonably possible;
(3) Keep finished beer as cold as possible.​

... which looks very similar to the advice @chthon gave in their post earlier in the thread there (link)

Cheers, PhilB

 

[northof49]

Hi northof49
... hmmm, but they do "own up" that their experiments were intended to find those results ... and when you consider what the "experiment" was supposed to be investigating (i.e. the impact on beer staling, of HSA ... staling being a thing that happens over time) do you suppose that evaluating the results "after sitting in kegs in my keezer for about a week" would ever have been likely to find that out?

Still, they only generate the ......... ... you posted the link to it, and I was dumb enough to follow it

Cheers, PhilB

Hi PhilB,
I agree that there are limitations to how far we can extend their results of what they report. They have done additional hot-side aeration ageing and low dissolved oxygen experiments to add to our knowledge base. I don't think that their efforts qualify as click bait, but I won't provide links as I don't want to appear to be driving traffic to the site. If you are interested, a search will take you there. I find that these results give me more to think about than the positions that the "experts" take on the issue. There is a lot of folklore that gets passed along without being tested. There are a lot of practices that made sense at one time but are no longer needed with current ingredients. Sorry if you thought reading about their experiment was a waste of your time. I'm not trying to change how you brew. In the end, I think that we are all free to take the steps that we think are necessary to brew what we like.
Cheers,

 

[PhilBrew]

Hi northof49

I'm not trying to change how you brew. In the end, I think that we are all free to take the steps that we think are necessary to brew what we like.

... OK, but then I'm not telling anyone how to brew either ... feel free to review my posts in this thread, you'll see I've not even expressed my own personal opinion about the topics discussed. ALL I've done has been to provide information for other members, so that they can make their own mind up ... I only responded to your post to point out how it linked to a reference that added "dubious value" into the body of knowledge (even the author admitted that it was subject to confirmation bias).

Cheers, PhilB

 

[northof49]

Hi PhilB,
I guess I place more weight on their results than you do. I don't see it as a problem that the author mentions that he performed the experiment with a preconceived idea about the outcome. Consider how he set up the experiment. He made two batches of beer with one difference (aeration during the mash) and then provided testers with three cups, two of one and one of the other (triangle test) to sample without telling them the nature of the experiment. The question the testers had to answer was is there one of the samples that tastes different than the other. The number that correctly identified the unique sample was not sufficient to make the results statistically relevant. There is nothing in that process that depends on the outcome that the experimenter expected. He mentioned his bias only with respect to his own sampling (he was not blind to the variable being tested). If aeration during the mash caused significant off flavours (oxidation producing ketones, aldehydes or esters) presumably the tasters would have detected this. I think that the fact that a statistically-significant number of tasters could not discern a difference in the samples is an important result and provides a valuable piece of information to our body of knowledge on the subject of hot side aeration. You are free to call the results dubious, and if you do I'll disagree with you.
Cheers,