Beer Forum

Hey guys,

I recently bought BeerTools and part of the purchase was a one-year GOLD Membership (Oooooohhh) which allows you access to their on-line database, recipe calculator, storage of favorite recipes, and articles on brewing,...it's pretty cool really,...more than I expected,...but anyway, I encountered a really interesting article written by Eric Watson on Debunking long-held brewing myths that on first pass I thought was heresy, but it really started making sense once I read further into the BeerTools message boards and the answers Eric was giving to the various questions he was receiving regarding the article - the guy seems to know his stuff!

Here's the blurb in a nutshell:

"WORT AERATION: If possible, don't! The reason is that it is not the wort that needs the oxygen, it is the yeast. By oxgenating the wort instead of the yeast starter, it will cause an over production of cells due to the excessive oxygen presence. This then leads to the production of unwanted esters and higher alcohols that will compromise beer flavor.

When oxygenating starters, you cannot use pure O2... the reason is that the uptake occurs too fast and without a dissolved O2 meter ($$$), you cannot tell when to stop. The way to properly do this one is to aerate using a high pressure aquarium pump, sterile air filter and a stainless steel aeration stone, all of which are redily available. It is virtually impossible to over-aerate using air, so you will avoid oxygen toxicity problems that will occur if trying to do this with pure oxygen." (Eric Watson; BeerTools.com)

What are your thoughts on this? In the forum's he further recommends a 5-day step-up process of your starter for various seemingly credible reasons that I won't go into here, but he says to start with a aerated (stone+aquarium pump+filter) 100ml hopped wort starter, add 200ml the next day, 400ml the day after that, and 800ml the final day for a whopping 1500ml of starter - of course this all depends on the style of beer you're brewing i.e. OG, etc., but it seems to make sense to me and I'm planning on giving it a go on my next batch and see what happens.

Let me know what you guys think. Later

Ryan Berg
Mill Creek, WA

blurry, Eric (Mesa) is a pretty darned nice guy and used to be the brewer at Title Town brewing -- he did a show on the BN about a year and a half ago.

He's not at Title Town anymore, but I think I might know how to reach him. If I can I will ask him to respond to your post.

Cheers,
Push Eject

I emailed Eric and Jamil about a month ago about this very subject. I think what it comes down to is the real reason yeast absorb oxygen is to reproduce, so if you pitch enough cells to ferment the entire batch right from the beginning you'll have a cleaner ferment. Which, I think, is part of Jamil's philosophy on pitching a good chunk of yeast (measured accurately of course) cold into his lagers. (less growth = less esters?)

If you were to over oxygenate the wort you would end up with too many cells that could lead to more esters and higher alcohols. But if you add all the oxygen to the starter you're just focusing on yeast growth and then you pitch the correct amount there shouldn't be a need for the yeast to reproduce in your wort. If you (as most of us homebrewers do) are not quite 100% accurate on your yeast growth then giving the wort some oxygen or aeration will help ensure the correct number of cells. I think the whole issue of over oxygenation is part of why these two great brewers recommend different procedures, and consequently is also one of the reasons John Palmer recommends aeration instead of oxygenation.

So basically as I understand it . . . pitch enough yeast and there's no need for growth so there's on need for introducing oxygen into the wort.

That being said, as a homebrewer who doesn't have the equipment to really monitor how much yeast I'm pitching, I aerate and keep an eye on my fermentation temps. Maybe when I can afford some lab equipment and a clean room.

I think this is a great debate and I'd love to hear Jamil and Eric's two cents in this thread.

"... I think what it comes down to is the real reason yeast absorb oxygen is to reproduce, so if you pitch enough cells to ferment the entire batch right from the beginning you'll have a cleaner ferment."

Yep!

"If you were to over oxygenate the wort you would end up with too many cells that could lead to more esters and higher alcohols. But if you add all the oxygen to the starter you're just focusing on yeast growth and then you pitch the correct amount there shouldn't be a need for the yeast to reproduce in your wort."

Actually, some of the yeast do continue to reproduce in the wort, it is just that the majority of the cells are fermenting or are ready to.


"... I think the whole issue of over oxygenation is part of why these two great brewers recommend different procedures, and consequently is also one of the reasons John Palmer recommends aeration instead of oxygenation."

Different proceedures? Mine is the same (which actually is not mine, it is what is taught at reputable brewing schools and is pretty much standard operating proceedure professionally). In my off-forum e-mail to you I mentioned that aeration is the best way to go because most people don't want to shell out big bucks for a dissolved oxygen meter. Since you are aerating 100% of the time (hopefully on a stir plate) you cannot use pure O2 in such a small volume of solution as it will most likely kill the yeast. It is impossible to cause yeast problems when injecting sterile air because of the lower % of oxygen in ambient air.

"So basically as I understand it . . . pitch enough yeast and there's no need for growth so there's on need for introducing oxygen into the wort. "

Sort of... If there is little dissolved oxygen in the wort, it will keep reproduction at a much lower rate and therefore will reduce the ester production as well as give a solid ferment. An overpitch can cause fermentation to go too fast (yes, there is such a thing) which will be detrimental to the beer's flavor and can cause the beer not to reach target FG.

Eric Watson
Green Bay Distilling
Green Bay, WI

Doh! ...and I just bought one of those oxygen regulator thingys.

Eric thanks so much for chiming in!! I always love to be in conversations that are way over my head. I'm glad I wasn't too off base.

BrewTard wrote:Doh! ...and I just bought one of those oxygen regulator thingys.

Brewtard, don't sweat it. There is enough grey area for everyone to be right on this.

Use your oxygen. Your yeast will love you.

Push Eject

Push Eject,

Thanx, I'm thinking that I'm still going to oxygenate my wort for a minute or two but I know now NOT to oxygenate my starter. It makes sense that in such a small amount of liquid I could over-oxygenate. Hmmm, do I see a new stir plate in my midst?

Thanks guys, awesome forum!