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fathand
11-12-2009, 10:17 AM
I have read in the NewBee section and it was suggested on the forum that you should aerate the Mead for the first 1/3 of fermentation.

I put together a batch of Wildflower mead last night and reluctantly aerated the carboy this morning before I came in to work. I am planning to aerate again tonight.

But I am conflicted because as a homebrewer you are not supposed to introduce oxygen after pitching the yeast but with mead it seems that is not the case.

Can someone please pacify my concerns about oxidation?

Arcanum
11-12-2009, 10:33 AM
Mead and the precursor must is generally more resistant to oxidation than wine/wine must and beer/wort. It's one of the nice little features of honey.

Aeration and staggered nutrient additions keeps the bulk of the yeast in aerobic/reproduction mode as long as possible. Aerobic-mode yeast metabolizes dramatically more sugar and thus produces dramatically more alcohol than stationary or anaerobic-mode yeast. That all results in a faster fermentation and less stress on the yeast. Less stress on the yeast means it's less likely to produce off flavors.

In the case of mead, at least until the 1/3rd sugar break, the benefits of aeration vastly outweigh any potential downsides.

Medsen Fey
11-12-2009, 10:37 AM
Well to start with, mead must is not as prone to oxidation as beer wort. I'm not saying that you can't oxidize it - you can - but it doesn't occur as easily. The yeast themselves need the oxygen in order to form healthy cell membranes to grow and divide, and to maintain resistance to alcohol as it increases in concentration. In wine and mead must, lack of oxygen exposure leads to stuck fermentation, and lower amounts of sugar consumption.

You don't need aeration to make beer in most cases because the yeast come packaged with enough sterols and lipids in their membranes from their production process (which uses plenty of oxygen) to easily ferment up to about 6% ABV. If you try making a high gravity barley wine type beverage, aeration becomes important, and using this technique will improve the outcomes.

You can read more Here (http://www.gotmead.com/forum/showthread.php?t=13252) and Here (http://www.gotmead.com/forum/showthread.php?t=12811).

I hope that helps.

Medsen

wayneb
11-12-2009, 11:42 AM
It is also common practice in winemaking to aerate early in the course of fermentation. As Medsen points out, the "rule of thumb" to never introduce O2 to a fermenting wort is really only applicable to beer and other beverages of similar alcohol concentration.

storm1969
11-12-2009, 12:12 PM
Red wine making involves constantly adding O2 to the must as you punch down the cap...

Oskaar
11-13-2009, 05:03 AM
I have read in the NewBee section and it was suggested on the forum that you should aerate the Mead for the first 1/3 of fermentation.

I put together a batch of Wildflower mead last night and reluctantly aerated the carboy this morning before I came in to work. I am planning to aerate again tonight.

But I am conflicted because as a homebrewer you are not supposed to introduce oxygen after pitching the yeast but with mead it seems that is not the case.

Can someone please pacify my concerns about oxidation?

I actually add O2 during my primary in beer making as well. Yeast need O2 to develop fully. During the very active stages of early fermentation in beer the aggressive off-gassing will strip any O2 not being absorbed by the yeast before it can cause oxidation. Tyler King who is the Director of Brewing Operations at The Bruery in Placentia, CA adds O2 to their fermentations early on, and in some cases almost all the way through the ferment.

Their Black Tuesday, Russian Imperial Stout is currently #3 in the top 100 beers worldwide, and #1 in the top 100 beers in the USA. They also have two more beers in the top 100 both worldwide and in the US.

See here (http://beeradvocate.com/top_beers)for a link to the Beer Advocate site for rankings.

I say do whatever makes you comfortable, but, don't let yourself fall into a rut over "rules" that you have not actively challenged yourself.

Hope that helps,

Oskaar

wildaho
11-13-2009, 06:39 AM
Number 1: understand that beer and mead have different needs.

Number 2: understand that the beer world needs to be shaken and stirred on occasion. For any beer over an estimated 8%, I have been following the aeration techniques for mead. Aerate the hell out of them until the 1/3 sugar break. If you do, you'll have better attenuation and cleaner ferments. Your aging times will be much shorter too.

Number 3: Ignore the mythology and open your mind. Charlie Papazian built a saga 30 years ago and it's been taken as gospel ever since. Us heretics have been playing around since then and have actual empirical data to back up our procedures. A book, or maybe three books, say it won't work. I have data to actually prove that mead techniques work for big beers too. Read everything with a grain of salt (including this). But until you try it, how can you honestly say that it doesn't work?

KCWortHog
11-13-2009, 03:07 PM
Adding oxygen to beer once fermentation begins WILL OXIDIZE your beer. That said, some beers are actually suited for oxidation - like barleywine, imperial stout, or some strong ales. Oxidation during will likely add a sherry component to beer, which is often desired in stronger, higher-gravity beers. But it does NOT belong in most beer and steps to avoid oxidation are warranted.

In other words, The Bruery intentionally oxidizes their RIS to add to the flavor and depth of the beer. It "works" because they WANT that flavor there. So I'd make sure that the sherry component is actually desired in your beer before you go introducing oxygen to primary. If you're making an Imperial IPA with 8%+ alcohol, you should not be introducing oxygen because the off-flavors caused by oxidation are undesirable in that style. IOW, don't go solely by your ABV but by the flavor profile of the beer. Old Ale? OK. Barleywine? Sure. Imperial Kölsch? Not so much.

And FWIW, I think most serious homebrewers have already been "shaken up" by John Palmer, Jamil Zainasheff, Ray Daniels, Greg Noonan, George Fix... those are the names I think most homebrewers have on their shelves these days. Including a dusty copy of Joy of Homebrewing. ;) (and occasional mentions of RDWHAHB :D )

phew, I feel better now. ;)

As for aerating must, I've been looking into this as well. A few people on here have said that simply shaking your carboy will both expel CO2 (which it will) AND aerate the must (which I don't believe). Since CO2 is heavier than air and is trapped in the headspace & neck of the carboy, how could O2 get "sucked down" into the carboy? The simple weight of the CO2 would prevent that from happening (and is precisely why purging kegs with CO2 is an effective way to avoid oxidizing beer when you rack it from carboy to keg).

So I don't know how a lees stirrer or shaking (or any method other than compressed O2 or an air pump) would work. Anyone know?

I promise the beer part of this post came out way more cranky than I really intended it to and I've tried to nice it up a bit but I clearly have an opinion on the matter, lol.

AToE
11-13-2009, 03:15 PM
As for aerating must, I've been looking into this as well. A few people on here have said that simply shaking your carboy will both expel CO2 (which it will) AND aerate the must (which I don't believe). Since CO2 is heavier than air and is trapped in the headspace & neck of the carboy, how could O2 get "sucked down" into the carboy? The simple weight of the CO2 would prevent that from happening (and is precisely why purging kegs with CO2 is an effective way to avoid oxidizing beer when you rack it from carboy to keg).

So I don't know how a lees stirrer or shaking (or any method other than compressed O2 or an air pump) would work. Anyone know?



The CO2 will diffuse out fairly quickly. I usually take off the airlock, give it a swirl or two to expel some dissolved CO2, then let it sit for a minute or so before putting a cap on it and shaking it to aerate. Then I open it again, let the CO2 dissapate, then cap it and aerate it again.

I use the same technique when using a lees stirrer.

CO2 is heavier, but it doesn't form a neat layer that will stay for long. Take off that airlock and it'll be gone almost immediately as far as I understand it.

KCWortHog
11-13-2009, 03:30 PM
Take off that airlock and it'll be gone almost immediately as far as I understand it.

But if CO2 is heavier than air, why would it float upward into the air when the airlock is removed? It doesn't - it stays put. (again, that's why you can purge a keg with CO2 and leave it open at the top while racking and not risk oxidation.) The airlock isn't there to keep O2 out; it's there to prevent contamination from ambient organisms.

So we know that:
1. CO2 is heavier than air. Therefore it will always be lower (in position) than ambient air unless O2 is placed underneath it.
2. There's nothing under the CO2 other than mead

So how is the O2 getting underneath the CO2 unless it's being placed there by something? CO2 is escaping the carboy because some is being expelled from the mead itself. Therefore, the CO2 being released from the body of the mead is pushing up on the CO2 in the neck/headspace of the carboy and expelling some of the gas. But the movement of gas is upward. And since CO2 is heavier than air, it is not logical that O2 would somehow magically move downward. That's the part I don't understand.

AToE
11-13-2009, 03:33 PM
When you remove the airlock, the CO2 stays put. It is heavier than the air outside the carboy, so it stays put (again, that's why you can purge a keg with CO2 and leave it open at the top while racking and not risk oxidation.).

So we know that:
1. CO2 is heavier than air. Therefore it will always be lower (in position) than ambient air unless O2 is placed underneath it.
2. There's nothing under the CO2 other than mead

So how is the O2 getting underneath the CO2 unless it's being placed there by something? CO2 is escaping the carboy because some is being expelled from the mead itself. Therefore, the CO2 being released from the body of the mead is pushing up on the CO2 in the neck/headspace of the carboy and expelling some of the gas. But the movement of gas is upward. And since CO2 is heavier than air, it is not logical that O2 would somehow magically move downward. That's the part I don't understand.


Someone will be along in a second to explain why it will dissapate quickly I imagine. I don't understand the process well enough to explain it properly to someone else, just well enough to grasp it for myself. It's not magic, I believe it is ozmotic pressure that will cause the heavier CO2 to dissapate, but that could be inaccurate.

Medsen's explained it a few times, and that CO2 will definitely be gone fast, simply being heavier than O2 is not enough, there are more physics at work than just simple weight!

KCWortHog
11-13-2009, 03:36 PM
That's what I'm looking for - and sorry, I edited my post to try to explain better :)

I think he posted something about it before, but the thread devolved into general chit-chat before a clear answer was provided. I hope someone can answer this for me as my husband and I have talked about this a few times now and still can't figure out how you're supposed to be able to aerate without a forced oxygen supply.

ETA - I do remember someone posting some studies about the relative effectiveness of different aeration methods (oskaar?), but I don't recall that they talked about it in the context of mid-fermentation.

AToE
11-13-2009, 03:41 PM
If it's not osmotic pressure I'm going to be embarrassed! Whatever the reason, it definitely works!

Medsen Fey
11-13-2009, 03:42 PM
Several people on here have said that simply shaking your carboy will both expel CO2 (which it will) AND aerate the must (which I don't believe). Since CO2 is heavier than air and is trapped in the headspace & neck of the carboy, how is oxygen supposed to get "sucked down"...

I'm going to leave the beer oxidation discussion for others who brew more than I do.

Now for the aerating in a carboy, keep in mind that just because CO2 is heavier than air does not mean that the two form into layers by weight like liquids do. Gases behave differently; In a closed space the molecules will bounce around to fill the whole space in a uniform concentration, so the minute any air gets into the carboy headspace, it will begin diffusing through the entire volume.

Even though CO2 is being produced, since there is a concentration gradient of Oxygen and Nitrogen on the outside of the carboy relative to the inside of the carboy (which essentially has none), the moment you take the airlock off, oxygen and nitrogen start to diffuse in. If you then begin swirling the mead and creating a vortex with a lower pressure in the center it will suck the oxygen containing gas down into the mead and oxygenate it. There is plenty of anecdotal evidence that this works because people are able to successfully brew very high gravity meads in a carboy without using starters - unless the yeast get oxygen (or other sterol supplementation) that isn't going to happen.

Now if you have a airstone and a pump (or an O2 tank) and want to use it, there's certainly nothing wrong with making use of technology. I personally don't do primary in a carboy - I typically use a bucket, and then I usually don't even seal the lid. I just have it loose on top to keep critters out. When I aerate, take off the lid and use the low tech approach with a whisk. About 30 seconds of that, and my yeast get plenty of O2. Some people just keep open fermenters (usually covered with a cloth to keep stuff from dropping in)

Just about any approach to give the yeast some oxygen works and which one you use is much less important than the fact that you use one. I'd love to see someone with an O2 meter measure the saturation of must with these different approaches to document it.

Medsen

Sorry AToE it's not osmotic; that refers to fluid shifts through a membrane due to concentration of solids. Nice try though! :)

Medsen Fey
11-13-2009, 04:10 PM
But if CO2 is heavier than air, why would it float upward into the air when the airlock is removed? It doesn't - it stays put. (again, that's why you can purge a keg with CO2 and leave it open at the top while racking and not risk oxidation.) The airlock isn't there to keep O2 out; it's there to prevent contamination from ambient organisms.



When racking if you flushed with CO2, it will give you a few minutes in which to rack before oxygen makes its way in the container. However, once you are done, you need to flush the air out of the headspace again because oxygen will be in that space if it was open to air during racking. This is why I sometimes rack from keg to keg without it being opened to air (that and because it is easier - I'm all about easier.)

The airlock is in fact there to keep air out. This is why you can store something under airlock for months or years without it oxidizing. If you store a mead in a container without an airlock you'll wind up with vinegar (if you're lucky) or just spoiled mead.

AToE
11-13-2009, 04:15 PM
Sorry AToE it's not osmotic; that refers to fluid shifts through a membrane due to concentration of solids. Nice try though! :)

Darnit!!!:)

KCWortHog
11-13-2009, 04:30 PM
When racking if you flushed with CO2, it will give you a few minutes in which to rack before oxygen makes its way in the container. However, once you are done, you need to flush the air out of the headspace again because oxygen will be in that space if it was open to air during racking. This is why I sometimes rack from keg to keg without it being opened to air (that and because it is easier - I'm all about easier.)

The airlock is in fact there to keep air out. This is why you can store something under airlock for months or years without it oxidizing. If you store a mead in a container without an airlock you'll wind up with vinegar (if you're lucky) or just spoiled mead.

Right. But the airlock is there to prevent ambient bacteria & yeast from getting in - not to prevent oxidation.

KCWortHog
11-13-2009, 04:40 PM
If you then begin swirling the mead and creating a vortex with a lower pressure in the center it will suck the oxygen containing gas down into the mead and oxygenate it. There is plenty of anecdotal evidence that this works because people are able to successfully brew very high gravity meads in a carboy without using starters - unless the yeast get oxygen (or other sterol supplementation) that isn't going to happen.

And they're not using O2 tanks or air pumps? :icon_scratch:


I typically use a bucket, and then I usually don't even seal the lid. I just have it loose on top to keep critters out. When I aerate, take off the lid and use the low tech approach with a whisk. Seems like that approach would introduce a lot more O2 than swirling a carboy because of the much wider exposure to air and the action of the whisk pulling air downward. Clearly I'm still struggling to see how to aerate a carboy without some sort of tool (and a lees stirrer still doesn't click for me - seems the 'vortex' wouldn't be strong enough - but I am fully willing to admit naiveté here).


I'd love to see someone with an O2 meter measure the saturation of must with these different approaches to document it.

Same! As well as some way to look at CO2 vs. O2 (if only we could color them!) and watch the patterns of movement by swirling a carboy around. I just don't imagine that rocking a carboy would sufficiently aerate... I need visuals! Diagrams! video! :)


When racking if you flushed with CO2, it will give you a few minutes in which to rack before oxygen makes its way in the container. However, once you are done, you need to flush the air out of the headspace again because oxygen will be in that space if it was open to air during racking.

Hmm, that's true. And I was thinking earlier too that if you open up a bottle of beer then re-cap it an hour later, even without moving it, you've introduced oxygen. I give up. :cool:

Medsen Fey
11-13-2009, 05:08 PM
Right. But the airlock is there to prevent ambient bacteria & yeast from getting in - not to prevent oxidation.

If you want to try if for yourself, make a nice fruit melomel of your choice, but make it a small batch; say a gallon. Then rack into a secondary container without topping it up so you have some headspace. You can flush it with CO2 if you like. Then put an airlock on it, but don't put any water in it, just keep the cap on. That will keep the critters out, but let air in. Then put it away and let it age for 6-12 months, and then try it.

If you don't like sherry, you won't like it.

AToE
11-13-2009, 05:15 PM
Seems like that approach would introduce a lot more O2 than swirling a carboy because of the much wider exposure to air and the action of the whisk pulling air downward. Clearly I'm still struggling to see how to aerate a carboy without some sort of tool (and a lees stirrer still doesn't click for me - seems the 'vortex' wouldn't be strong enough - but I am fully willing to admit naiveté here).


I don't think most people just swirl, they also slosh it so that it splashes. Swirling pulls O2 down (or just leaving it open for a bit lets O2 in) then splashing actually mixes it in. I shake the heck out of 1 gal batches.

And for the lees stirrer, also used in a way to not just cause swirling and mixing. If you put the stirring end of the lees stirrer an inch or two below the surface and then pull the trigger you'll get intense splashing, that's what'll do the actual thorough aeration.

KCWortHog
11-13-2009, 05:44 PM
I had no idea the shaking-aeration method was so vigorous. I thought it was just swirling/rocking, avoiding spillage. I told you I need videos ;) (doesn't really matter, as we have an O2 tank, but I've been wondering about this on principle.)

So, basically, the take-away here is that with vigorous enough activity, the CO2 displacement will be enough to let oxygen in to the carboy. Makes sense.

I'm still skeptical on the leaving-off-the-airlock concept oxidizing mead/beer/cider/etc ONCE the layer of CO2 has been created, but I won't beat that dead horse anymore :)

ZachR
11-13-2009, 06:05 PM
http://upload.wikimedia.org/wikipedia/commons/e/eb/Diffusion.gif

As someone mentioned earlier, a layer of CO2 doesn't last long (unless protected from incoming gases by an airlock) because of diffusion. High energy gas molecules are constantly bouncing around, and given enough time, the CO2 will completely "dissolve" in the surrounding air, just as sugar or salt will eventually dissolve in a glass of water even without stirring.

As for aerating wort/must, vigorous shaking (I usually shake carboys for about 10 minutes before I pitch yeast and about 5 after) helps dissolve oxygen from the air into the liquid faster. Gases will still dissolve in the liquid even under atmospheric pressure, but it will be at a much slower rate than shaking.

KCWortHog
11-13-2009, 08:18 PM
The salt/sugar comparison doesn't really cut it though because both salt & water are more dense than water - so of course they'll fall & dissolve. Here's how I've always thought of it - say oil is air and water is CO2. Put some sand at the bottom of a bowl, then add water, then float oil on top of it - the oil stays put. It doesn't slowly "dissolve" into the water and rest on the sand.

Swirl them around and you get pretty much the same result - some oil might dip below the surface of the water, but it doesn't get to the sand. That's exactly how I've pictured "aerating" mead by swirling. Now, take a whisk to it or shake it and make a mess, and that's a different story.

Oh, and I may be strong for a woman, but I can't shake a 6-gallon carboy for 10 minutes. Those things are heavy! :cool:

Medsen Fey
11-13-2009, 09:03 PM
Instead of oil and water, think ethanol and water. Ethanol is much lighter than water - compare the sp. gr of each. When you pour ethanol on water, the ethanol doesn't float, it mixes in. CO2, nitrogen, O2, argon and other gases mix equally well.

Dan McFeeley
11-13-2009, 10:23 PM
I think the basic principle fueling gas diffusion is brownian motion -- Medsen already touched on it when he described gas molecules bouncing around in a closed space. Regardless of the weight of the gas, it will spread out occupy all available space, mixing with other gasses, as the individual molecules ricochet all over the place.

An everyday example -- if this didn't happen, the individual gasses in the athmosphere would form layers one on top of the other and there would be no life as we know it.

Aeration -- the shake rattle and roll method works, but it's gotta be really vigorous, with maybe half the volume of the carboy taken up by the must to allow sufficient mixing of the must with air, and even then it's the least efficient method of aerating the must. Although I prefer to use an airstone, I've shook up large batches of JAO just because it's how Joe said to do it. I'll fill half the carboy, using all the honey, shake it up good for a while, then fill up the rest of the carboy with water and swirl to mix it.

--

wildoates
11-13-2009, 10:43 PM
Also, polar solutions dissolve only into other polar solutions, the same goes for non-polar solutions. That's why oil and water will never "diffuse" without an emulsifier. Substances also must be soluble, which is why sand doesn't dissolve into the water. While it is true that gases have differing densities and denser ones will start out on the bottom, they won't stay there for the very reasons stated.

I used to do (when I taught this stuff) a little demo to illustrate this--I'd spray a fine mist of a very nasty cologne in the far reaches of the classroom without saying anything to anyone. Now, if density was the only issue, since the cologne molecules are heavier than air they should just fall to the floor, but it volatilizes and soon spreads to all corners of the room until the cologne molecules are more-or-less evenly dispersed in the room air.

CO2 does the same thing in a carboy unless the headspace is completely filled up with CO2, all room air is pushed out, and it's then airlocked. It hopefully won't smell as bad as that vile cologne did, though. Ewww.

wildaho
11-14-2009, 05:53 AM
Adding oxygen to beer once fermentation begins WILL OXIDIZE your beer... {snip}

And FWIW, I think most serious homebrewers have already been "shaken up" by John Palmer, Jamil Zainasheff, Ray Daniels, Greg Noonan, George Fix... those are the names I think most homebrewers have on their shelves these days. Including a dusty copy of Joy of Homebrewing. ;) (and occasional mentions of RDWHAHB :D )... {snip}

I promise the beer part of this post came out way more cranky than I really intended it to and I've tried to nice it up a bit but I clearly have an opinion on the matter, lol.

KC,

How long have you been brewing? And how much of what you are saying is based upon the books you named and what is your own personal experience? I'm thinking that you are believing the "gospel" of the gurus rather than testing the limits yourself. Palmer and Daniels in particular are little more than a regurgitation of Papazian. Noonan & Fixe were more concentrated on lagers. Jamil is like Oprah, popular, perhaps, but? You couldn't have made my point any better if you tried.

Always question authority. Otherwise you will always be a sheep, rather than the Shepard. We encourage people here to try new things. Open your mind a bit and you might be surprised. But until you try it, you can't deny it based upon other doctrines that you haven't tried either. I hate to bring parallels to religion but...

The figures you name are all estimable. But they are all aiming their procedures around beers that are around 5-6%. I prefaced my post by saying that I was only talking about beers that exceed 8%. I've hit over 14% on some of my beers by adapting mead techniques. I stand by my post. Like I said, I have empirical data to back it up over the last 14 years.

So, are you a sheep? Or do you wanna be a shepard? Your choice.

:cheers:
Wade

KCWortHog
11-14-2009, 12:11 PM
wildaho I have been brewing since 2003. And I think you misunderstood my post.

The Bruery *is* oxidizing their beer - but they are doing it on purpose because it contributes a desirable character to their product. I thought that Oskaar was saying that introducing oxygen to the beer throughout fermentation won't oxidize high-alcohol beers. Perhaps that's not what he was saying and I misunderstood the intent of his post - clearly that'd be the first time that's ever happened on the internet. ;)

And btw I don't disagree with you about adding O2 to high gravity beers in the first 1/3 of fermentation. i think you misunderstood *my* post as well :) To summarize:

1. I thought Oskaar was saying that adding O2 to high-gravity beers won't oxidize them
2. I think you thought I was saying no one should ever add oxygen to high-gravity beer

On re-read I suspect neither is correct... :)

(eta - and FWIW, I use an O2 tank to oxygenate my wort and I do aerate my must both at pitching and 24 hours after pitching with my nutrient addition. now that I know more about the 1/3 sugar break, I"ll rely on that instead of time duration for aeration. Just wanted to make it clear that I'm definitely a proponent of oxygenating must/wort but not of intentionally oxidizing beverages when it's not appropriate for the style! :) )

Oskaar
11-15-2009, 12:28 PM
wildaho I have been brewing since 2003. And I think you misunderstood my post.

The Bruery *is* oxidizing their beer - but they are doing it on purpose because it contributes a desirable character to their product. I thought that Oskaar was saying that introducing oxygen to the beer throughout fermentation won't oxidize high-alcohol beers. Perhaps that's not what he was saying and I misunderstood the intent of his post - clearly that'd be the first time that's ever happened on the internet. ;)

The Bruery is oxygenating not oxidizing their beer. Small doses of oxygen through the early stages of fermentation, and in some cases throughout fermentation will not "oxidize" their beer. There are no reductive characters, aromas, flavors or compounds in their beers that arise from the introduction of oxygen, hence no oxidation, and their beers are not oxidized.

Again, I'm talking specifically about increasing the amount of dissolved oxygen in the must or wert, not oxidizing the must or wert which indicates a reductive or off-character that detracts from the overall character of the finished product.

Oxygen is required during the early aerobic fermentation in order for the yeast cells to develop fully and form strong and elastic cell walls. Oxygen should be considered an essential yeast nutrient and slight aeration during yeast stationary and growth phases increases the production of lipids (principally oleanoloic acid) and sterols (ergosterol and zymosterol) which are important cell membrane constituents. This is important for the fermentation when it goes into heavy alcohol production (most of the alcohol is produced in the early 1/3 of the fermentation according to Dr. Clayton Cone of Lallemand) it is also a key in the yeasts ability to withstand the toxic effects of the EtOH level as it rises during fermentation.



And btw I don't disagree with you about adding O2 to high gravity beers in the first 1/3 of fermentation. i think you misunderstood *my* post as well :) To summarize:

1. I thought Oskaar was saying that adding O2 to high-gravity beers won't oxidize them

What I'm saying is that oxygenating/micro-oxygenation of beers during the logarithmic growth curve of yeast will not "oxidize" beer, mead or wine. There are also instances where oxygenation is used throughout the entire fermentation process to the benefit, not oxidation of whatever is being oxygenated.



2. I think you thought I was saying no one should ever add oxygen to high-gravity beer

On re-read I suspect neither is correct... :)

(eta - and FWIW, I use an O2 tank to oxygenate my wort and I do aerate my must both at pitching and 24 hours after pitching with my nutrient addition. now that I know more about the 1/3 sugar break, I"ll rely on that instead of time duration for aeration. Just wanted to make it clear that I'm definitely a proponent of oxygenating must/wort but not of intentionally oxidizing beverages when it's not appropriate for the style! :) )

Sounds like we're pretty much on the same page. I don't use one rule for everything that I make. Some stuff I oxygenate only early on, other stuff I will leave open (but covered with a cloth to keep out chunky stuff) through out most of the fermenation but cover with an airlock at the first racking.

Also, if you leave an airlock off mead, beer and wine will all oxidize, mead not as quickly as beer or wine, but it will go to oxidation just as the other two will without an airlock. You can prove this to yourself with a small test batch as Medsen suggested. I'll go a step further and say instead of an airlock, just cover it with a cloth and secure it in place so you don't have critters swimming around in the mix.


Hope that helps,

Oskaar