Oxygenating Big why?

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Wort*hog

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I keep reading about the need to oxygenate the wort with AG but haven't seen any suggestion on doing it with extract. Whut'z up with that?
 
Wort*hog said:
I keep reading about the need to oxygenate the wort with AG but haven't seen any suggestion on doing it with extract. Whut'z up with that?
It doesn't matter if you are extract or AG brewing. If you are using liquid yeast, the wort needs to be oxygenated. :mug:
 
I think one reason it's emphasized in AG but not extract is because of the size of the boil. In AG, you boil all the wort. This takes the oxygen out of it. In extract brewing, most brewers are boiling 2-3 gallons and then adding water. When I did extract boils, I added tap water and used my sprayer hose. I had tons of foam, and this added oxygen. I also stirred, shook, etc.

But because you can't add water with a full boil, it's even more important to oxygenate/aerate.

Lorena
 
orfy said:
It's all about the type of yeast, not the wort.

Do you mean "it's all about the quantity of yeast"? As I understand it, aeration puts the yeast into an aerobic cycle which causes the cells to reproduce. Picture a bunch of yeast riding stationary bicycles. Ok. That has nothing to do with anything. Anyway, the reproduction phase increases the number of yeasties, but during this time, no alcohol is being produced. It's only when the yeast go anaerobic that they start excreting alcohol.

I think of it as being like our muscles. So long as there is stored oxygen in our red blood cells, we can excercise and whatever, but once our muscles run out of oxygen, and we're breathing as hard as we can, and our oxygen demands out-strip the supply in our blood, then our muscles start using up stored energy. This stored energy can be converted to power without the use of oxygen. And the byproduct is lactic acid. That's what makes your muscles sore after a long work out. Your muscles convert to using a different chemical process to keep you active. Yeast kind of do the same thing, but instead of producing lactic acid in their anaerobic stage, they produce alcohol as their byproduct. This is what brewers depend on.

So, adding oxygen makes the yeast multiply, but it doesn't help you produce alcohol. However, once the O2 is used up, then the yeast stop reproducing and, however many there are, set about eating the sugars for energy and begin pissing out alcohol. Yes, alcohol is a secretion/waste product to the yeast. Imagine a bunch of yeast pissing in your beer. Again, that has nothing to do with anything, it's just what's happening.

So, if you have a starter and a ton of yeast, maybe you're completely happy with them going straight to an anaerobic alcohol-producing phase. However, if you think you don't have enough yeast to kick the butt of any infection that may be trying to take hold, then you want the oxygen there to increase the size of your yeast army. Imagine a bunch of zombies stripping the clothes off of lindsay lohan and giving her much sexual pleasure. That has nothing to do with anything, but it is an amusing thought.


Hope that helps.
 
I am a big fan of doing what works for you. I have never airated my wort and have never had aproblem yet. i do full boils , I hit all the targeted gravities , and best of all my beers turn out great. I use liquid yeast only so far, maybe that is why? But others here use oxygen and airation stones........that works for them.
 
Wort*hog said:
I keep reading about the need to oxygenate the wort with AG but haven't seen any suggestion on doing it with extract. Whut'z up with that?

Personally, I suggest it on all batches. Even on my partial mash batches, I still aerate, and ever since I started doing it, my attenuation %'s have improved drastically.

As Lorena said, the reason it's not required on extract is because when you boil water, you boil out the oxygen. But since extract batches usually have several gallons of UNboiled water added at the end, there's a good amount of it already there. But as I said, it has never hurt anything to aerate your wort, extract or no.

Two rules for short lag time and healthy fermentation: make a big (1L) starter with yeast nutrients added, and aerate plentifully.
 
I just had a stuck fermentation because of lack of aeration (I am pretty sure). My first couple brews went fine without really aerating but the last one stuck well above where my FG should have been. It still tastes allright, but I won't make the mistake again.


Dan
 
I'm interested in some of the experiments I'm reading about with this subject... This weekend, I'm going to brew ten gallons of my "standard pale," split it into two fermenters, aerate one by simply fanning the beer out on the sides as it goes in, and the other with pure O2 and the aeration system from Williams... I'll post the result if anyone's interested.

-p
 
Sounds good, you'd be confirming my results as well and since so many people want to see it repeated it will be appreciated. You'll end up with two different FG's probably only a few points apart but I'm sure they'll both be good.
 
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