aeration is it really needed?

[Ryanh1801]

I see lots of guys on here have some sort of way of aerating the wort before pitching . I was considering buying a o2 kit when I started doing all grain. But on my last two all grain batches I have forgot to do any sort of aeration, Just siphoned into my carboy and pitched my yeast. Both of these beers I had airlock action in 8 hours( no starter with liquid yeast). So I ask this, is it really necessary? From what I have read the only reason to aerate is for the yeast, which I have not had a problem with with no aeration, so im having a hard time to change anything. Granted I have yet to brew a "big beer" which may be the reason. What are yalls thought?

 

[Pabst Blue Robot]

Is it really necessary? Certainly not. You will even get faster starts without aeration because the yeast's reproductive phase doesn't last for as long. Chances are, however, that your attenuation will suffer as a result of not aerating, and it can be difficult to brew high gravity or dry beers.

John Palmer has this to say on the subject:

[FONT=Verdana,Arial,Helvetica,sans-serif]

Yeast need oxygen to synthesize sterols and unsaturated fatty acids for cell membrane biosynthesis. Without aeration, fermentations tend to be underattenuated because oxygen availability is a limiting factor for yeast growth—the yeast stop budding when sterol levels become depleted.

[/FONT][FONT=Verdana,Arial,Helvetica,sans-serif]

I have just started aerating with an O2 system in the last several months, and I've noticed improvements in my attenuation and the vigor of my ferments in general. I've also noticed a slightly longer lag time, but it tends to finish more quickly despite that.
[/FONT]

 

[DeathBrewer]

i've just shaken the beer on lower abv beers and never had a problem. i had terrible problems with some of my big beers, which my aeration kit (aquarium pump, 2 micron stone) seems to help. that's all i got

 

[Ryanh1801]

I have been getting great attenuation also, maybe too much compared to my extract but I think that has to do with my mash temp. Got a better thermometer on the way.

 

[Drunkensatyr]

Great attenuation and every time I forget to aerate, I notice more off flavors.

 

[Yooper]

I think that's probably right- stressed yeast may lead to slight off-flavors. When you aerate and use a clean tasting neutral yeast, you'll notice better flavor overall. Fermentation will still happen, and beer will be made. I aerate and have been very happy with my results.

 

[brewt00l]

I did a little unscientific experiment the other weekend. I brewed a batch Saturday and aerated the heck out of it. The Sunday batch received much less aeration (to the point of almost none). Both batches used different strains of dry yeast that I have used numerous times.

Granted, there are a number of variables not accounted for but the Sat batch went off like a rocket, spewed krausen out the blow-off tube and attenuated very well. The Sun batch took longer to exhibit signs of any vigorous fermentation, fermented much slower and did not attenuate as well as I typically expect.

OTOH both batches tasted phenomenal when transferring to the secondary but the Sun batch has a slew of hops that would mask many off flavors produced by the yeast.

Bottom line for me is that I don't see why I wouldn't sufficiently (from my POV) aerate all future batches.

 

[Evan!]

I'm also firmly in the "aerate like it was your goddamned job" camp. When I started aerating (got one of them $30 aeration kits from AHS), my attenuation shot up and my batches got better. Whether or not you use a starter, and the size of said starter, govern lag time more than aeration does...

 

[ColoradoXJ13]

note though that in Papazian's second book, he has a section on yeast health and one can over-aerate and it supposedly causes the yeast to stay in the oxidative stage too long.

 

[Evan!]

note though that in Papazian's second book, he has a section on yeast health and one can over-aerate and it supposedly causes the yeast to stay in the oxidative stage too long.

Surely one can over-aerate...you just have to use your equipment as suggested. Aeration kit's suggested usage is 20-60 mins.

 

[user 4295]

Short lag times are not the holy grail that some would like to believe. A short lag time may simply be due to the fact that the yeast in an under aerated wort run out of oxygen too quickly and stop reproducing and begin the attenuation phase with a lower than anticipated cell count. This will lead to an under attenuated beer.

Since I began using O2, my lag times have actually increased due to the longer adaptive phase (reproduction), but I have experienced better attenuation across the board, ie., small beers all the way up to barleywines.

 

[Moonpile]

Surely one can over-aerate...you just have to use your equipment as suggested. Aeration kit's suggested usage is 20-60 mins.

My buddies and I just got a Mix-Stir. We used it to aerate our first batch of mead, and boy did that thing take off fast (it even had a blow off inside of 22 hours)!
We used it for 2 or 3 minutes, whipping the surface.

In the past we've aerated by using the bottling bucket like a big funnel into which we strain the wort. Then we drain into the fermenter which caused a lot of splashing. This seemed to work pretty well, though we came up a bit shy of expected attenuation.

Any reccomendations as for how long to use the mix-stir to achieve optimum aeration? I'm thinking we'd put about half the wort into the carboy and go at it for X number of minutes, keeping the mix stir near the surface of the wort so it whips and splashes, and then add the remainder of the wort.

 

[gonzoflick]

If you are not doing full boils then I dont think you need to aerate at all. I simply pour the last couple of gallons on water from a good height into my funnel and then into the carboy and that alone should aerate them enough. I've never done a full boil so I wouldnt know how to respond if your doing that.

 

[Yooper]

When I was doing extract brews, I never really aerated either, since I used tap water to top up and that had plenty of o2 in it. If you boil your tap water, though, you need to aerate and if you're doing full boils, too.

 

[cpbergie]

What about if you are using a good sized starter? Wouldn't the starter create enough yeast that you don't really need them to reproduce in your primary and they can just start fermenting?

 

[Bobby_M]

What about if you are using a good sized starter? Wouldn't the starter create enough yeast that you don't really need them to reproduce in your primary and they can just start fermenting?

As long as you have an effective starter to begin with you're right. You need to aerate your starter to acheive the best yeast reproduction possible. Then when you pitch, you have a ton of cells all ready to go to work and pitching into an oxygen deprived wort gets them fermenting immediately.

 

[Ryanh1801]

good info guys and galls. So i guess in short, a shorter lag time is not key. Not aerating can cause the yeast to be stressed and lead to off flavors. So i guess i should start looking for an aeration system.

 

[tdiowa]

I too aerate with O2 and stone. I have noticed a longer lag time. I also have noticed a better tasting overall product. One question though. I have always aerated and then piched my yeast. What would happen if I threw the yeast and then aerated??

TD