Aerate Wort with Yeast

Most of the directions I've read say to aerate the wort and then pitch the yeast. Today I brewed my first batch and did it a bit differenly. I poured my cooled wort between two 6.5 gal ale pales 5 times (lots of StarSan foam!). I then pitched my decanted yeast starter into the wort and proceeded to pour back and forth 3 more times...even more foam! Is there an issue with really mixing in the yeast so much into the wort? I'm just curious as to why more people don't use this method?

BTW: I pitched at 4:30PM and by 8:00PM I was getting bubbles every 2 sec...and yes, I know bubbles really don't mean much

Bubbles mean a lot. It's the lack of bubbles that doesn't mean much (leak in system). The start of bubbles means it's working ..... I wish my Brett starter would play ball.

If you keep transferring from one fermenter to another, you add additional risk of contaminating the wort. I cover my fermenter and swirl the wort as much as I can. I deliberatly cover it to minimize potrential for contamination.

It doesn't matter if you aerate before or after you pitch your yeast. Just make sure you do so. The splashing between buckets is a short term fix (and many do it), but like the above poster said.... I did it once and seen so much opportunity for a spill and a huge mess, let alone contamination...

I just give mine a vigorous stir with a lifting/splashing kind of motion. If it starts to foam, I'm doing it right.

I always aerate after I had the yeast. I also cover it and shake like crazy!

dgoldb1 said:

I poured my cooled wort between two 6.5 gal ale pales 5 times (lots of StarSan foam!). I then pitched my decanted yeast starter into the wort and proceeded to pour back and forth 3 more times...even more foam! Is there an issue with really mixing in the yeast so much into the wort? I'm just curious as to why more people don't use this method?

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I don't see any problems with what you did. I just give it a 90 seconds blast of O2 after racking to the carboy. Much easier than transferring the wort between two ale pails 8 times, and it also adds more O2.

-a.

I was reading in the Homebrew Digest that its good to aerate it a second time on the second day of fermentation.
"The best time to introduce oxygen into the wort is on the second day of the fermentation. The yeast need it the most at this time. Some commercial breweries are beginning to adopt this technique." - http://hbd.org/hbd/archive/4324.html

is this a good idea? if so, whats the best way to do it?

Not sure I would trust to much homebrewing information from 2003.

the main reason i was wondering was that the instructions i used didn't stress aerating much and i was wondering if i should aerate more, though the wort's been in the fermenter now for 16 hours

Oxygen in the wort is primarily added because the yeast need it to reproduce. Once they start eating sugar, they are done with oxygen. If you pitch a healthy active starter that you aerated well and repeatedly, or a dry pack of yeast containing several hundred billion cells, you don't need to aerate the wort for most recipes. With high gravity stuff, particularly wine and mead, the science changes a little bit.


Edit: aerating like you did certainly won't hurt things, except where it was mentioned it's more exposure to possible contaminants. Your fermentation will certainly finish more quickly than not aerating. My point is that it isn't usually necessary, and shouldn't generally be a source of stress, considering how many other more important things can go wrong in a fermentation.

Fletch78 said:

Your fermentation will certainly finish more quickly than not aerating. [/I]

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what will a quick fermentation cause? anything noticeable?

I'm getting a bubble every second now. This thing is fermenting like crazy!

It might cause a mess if it's too vigorous. Other than that, generally speaking, quicker is better. But the difference between 5 days and 6 days shouldn't be all that much of a concern unless you choose to make it a concern. If you underpitch, and don't aerate, you run into slower fermentations or stressed yeast, and that could affect the flavor, it's really as complicated as you want to make it.

Oxygen= yeast need it to multiply

If you pitch a proper amount of yeast, you don't need to worry about aeration. That's the whole point of making a starter.

That's my opinion and there are many other opinions.

Check out this series of interviews with brewing expert, Eric Watson, on Beer Tools:

http://www.beertools.com/html/articles.php?view=245

Here's Eric's surprising advice on aerating wort:

"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."

When using dried yeast, he recommends no aeration at all. The yeast was properly aerated before drying and has been properly prepared for the fermentation immediately. Just rehydrate the yeast (he recommends 90deg water) for 30 minutes and dump into the non-aerated wort.

That's some wild and crazy stuff, huh?!!!

My personal experience backs up the oxygen toxicity problem. I used to pitch the yeast then aerate with pure O2 for several minutes. The result was huge lag times and slow ferments.