Aeration.

"Aeration, aeration, aeration."
"How to brew fantastic beer guaranteed." Aerate right!

Is there too much emphasis given to the importance of lots aeration?
My last brew was aerated and pitched on a yeast cake from a previous brew. It had a vigorous ferment in 45 minutes and finished fermenting between 12 and 24 hours. I'm not yet sure if the beer will suffer. I'd say no way would that brew of benefited or coped with O2 injection.

This last brew I didn't aerate after it was in the fermenter. I didn't use a starter. I do rehydrate and feed the yeast a couple of hours before. 12 hours later it's got a nice 12.5" krausen and is bubbling away nicely. I just wanted to see if I needed to shake the crappola out of it for 5 minutes and if it made a difference.

I know some of you guys use oxygen and are happy with the result, so why fix it if it ain't broke. I'm not suggesting to stop but I'm down at the bottom end of the scale and wondering if I need to put any extra effort in.

Is there any yeast boffins out there that know how to do yeast calcs? Is it possible to work out the rate of increase of yeast given 1 pack off 11g dried yeast gets 1 teaspoon of sugar and 3 hours?

Long live KISS

Aeration is all about yeast growth. Pitch on a cake or use a quality dried yeast and aeration is less important. A fast ferment is only a problem if the wort overheats.

This is without a yeast cake or starter and without aditional aeration.
<24hrs.

Haha, suckers. Never once had a blowoff, in 26 batches. Sure, since I said that, my next one will blow off...but none so far.

Anyway, I've said it before, but using an aeration kit for 20-60 mins on my wort has increased my average attenuation levels by at least 10%. If you're getting good attenuation levels that are in line with the range for that yeast, then you shouldn't change anything...as long as the beer tastes good. And there isn't any problem with fast ferments except, as david said, possible overheating.

I was under the assumption that aerating helps ferment the sugars at the bottom. The stuff on top is O2 rich to begin with, right? It's the bottom of the carboy that needs to breathe.

As for attenuation I'm hitting my 1010/1012 targets.
I really don't think aeration will help me at all. If I start getting problems then obviously I consider it.
I don't like real fruity beers so don't want too much ester production.
When a wort gets going with fermentation there's so much movement and cirulation in it there shouldn't be any difference in fermentation at the top and bottom.

If you're having no problems, great. But, it's one of the factors that can impact attenuation, so if someone is having problems, it's something that they ought to consider. I've invested in an O2 system because I'm sick of lifting and dumping a keggle through a strainer (my current "system", in part because my siphon tube is a POS, but that's soon to be rectified).

I agree.

It just seems to be one of the things I can cut from my brew day. After all the reading I've done on the importance of it I'm really surprised that it doesn't cause me any problems. Saying that maybe the gadget I use to drain the kettle really does work well and I am getting really good aeration from it.

I'm just wondering if any one else gets good results without additional aeration.

orfy said:

I'm just wondering if any one else gets good results without additional aeration.

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I used to get good results from the "shake and ferment" method. I usually saw good attenuation and didn't have stuck ferments. However, my back is tired of it and twisting the knob on a regulator for 1-2 minutes is convenient.

It might be interesting to brew 10g and aerate 5g and not the other. The assumption I would make is that the yeast would multiply faster and healthier in the aerated batch while they would generate some by-products in the non-aerated batch. I have to taste things like that side by side to make any kind of reasonable comparison.

My air pump died and I just haven't gotten around to getting another. I have done 2 batches without it and have not noticed any problems with attenuation or slow ferment.

I thought the point of aeration was to help increase the initial amount of yeast the propagate before they start going to work on the fermentables. That being said, I have a very bizzare aeration technique, which I have "fine-tuned" more with each batch:

I live in an apartment, and there's no way in hell SWMBO would let me brew inside, and I can't imagine doing it on one of our patios either, really. So I brew at my job, a pub, and then haul the full carboy home with me. Between lugging it to the truck, driving home, and then lugging it up three flights of stairs, it gets shaken like crazy. In fact, yesterday, when I got home yesterday, I actually parked, and then tapped on my brakes over and over for a few minutes, which jostled the carboy back and forth way more than usual even. I think it's been pretty effective.

I hit the high end of the WLP550 attenuation (85%) using my strainer method. I can see for other reasons (like Baron says with the back). No doubt that the injection works, but if you have another method that works and are happy with the results then it's all good man. Like david says, yeast in the lag phase are needing that O2. Transferring onto an established colony I don't think you need to do anything.

Interestingly enough I came across this:

http://consumer.lallemand.com/danstar-lalvin/fortnightyeast.html#oxywort

:fro:

From Danstar's web site.

Pitching Rate: 1g/L

Step 1.

* Sprinkle the yeast on the surface of ten (10) times its weight of clean, sterilized (boiled) tap water at 30 - 35&#176;C (86&#176; - 95&#176;F)
* DO NOT STIR !!!
* Leave undisturbed for 15 minutes at 30 - 35&#176;C (86&#176; - 95&#176;F)
* Foam or no foam is not an indication of vitality

Step 2.

• After 15 minutes stir until all yeast is suspended
• Leave undisturbed for another 5 minutes.
• Adjust temperature of solution to that of the wort in 10&#176;C (18&#176;F) steps, by adding small amounts of wort at 5 minutes intervals and mixing gently (ATTEMPERATION)

Step 3.

• After attemperation inoculate without delay.
• Aeration of wort is not necessary

The only thing with this is 1g/l I pitch 11g in 23L but I do feed the yeast and leave for around 3 hours.

Aeration isn't as important with dried yeast in my experience. There is a reason for this, but I can never remember.

orfy said:

[*]Adjust temperature of solution to that of the wort in 10°C (18°F)

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10*C = 50*F

So if picthing on a cake, aeration is unneccessary, or just does not need as much time?

- magno

mysterio said:

Aeration isn't as important with dried yeast in my experience. There is a reason for this, but I can never remember.

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I belive that dry yeast packets have a much much higher cell count than liquid yeasts, so they do not need to reproduce as much.

Exactly, thus proving my original point. Aeration is to increase cell count before fermentation begins. Dry yeast is super concentrated. Supposedly White Labs vials have enough to get going on their own, but I've had much quicker starts the two times I used starters and increased the cell count than the two times I just pitched straight from the vial. All my fermentations with dry yeast have been as fast as the liquid w/ starter fermentations. That being said, my next wort is going to be pitched onto a yeast cake. I can't WAIT to see that lag time! :rockin:

magno said:

I belive that dry yeast packets have a much much higher cell count than liquid yeasts, so they do not need to reproduce as much.

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That's one reason, there's something else, too. Something about dried yeast having oxygen/nutrient stocks already.

Orfy,
From your posts it appears that you are using dry yeast. My understanding is that dry yeast doesn't require aeration like liquid yeast does.
My experience is that liquid yeast requires more attention. I think starters and aeration are key to good fermentations with them.
I've recently tried Safale dried yeast in my pumpkin ale and I was very impressed with the results. I had a certified beer judge tell me that it could win a contest. I didn't even rehydrate before pitching and I had active fermentation within 4 hours. I will be one happy camper if Safale comes up with more strains of dried yeast.

Torchiest said:

I thought the point of aeration was to help increase the initial amount of yeast the propagate before they start going to work on the fermentables. That being said, I have a very bizzare aeration technique, which I have "fine-tuned" more with each batch:

I live in an apartment, and there's no way in hell SWMBO would let me brew inside, and I can't imagine doing it on one of our patios either, really. So I brew at my job, a pub, and then haul the full carboy home with me. Between lugging it to the truck, driving home, and then lugging it up three flights of stairs, it gets shaken like crazy. In fact, yesterday, when I got home yesterday, I actually parked, and then tapped on my brakes over and over for a few minutes, which jostled the carboy back and forth way more than usual even. I think it's been pretty effective.

Click to expand...

this is admirable...

mysterio said:

That's one reason, there's something else, too. Something about dried yeast having oxygen/nutrient stocks already.

Click to expand...

Give that man a cigar. That is excatly right.
Another thing I see is with proofing yeast with sugar. IMO, not a good idea as the yeast cells taking in sugar not wort derived, makes it more difficult to change over to the sugars from the wort.
Not saying it don't work, just not the best.

I don't think that sugar is a problem if you use little enough to proof that it won't effect the flavor of the beer.

I would be more worried about osmotic shock if you use a high gravity sugar/wort to proof your yeast.