oxygenating double batches

[Jephro]

When brewing a double batch on two consecutive days it has always been my practice not to oxygenate the second batch. Is this how most of you do it? I have debated with several brewers on this topic.
What do you think??

Jeff Byrne

[pbutlert]

Hi, I aerate on only the yeast pitch batch. We do double brews usually in one day, and triple brews over a 2 day period. All the yeast is pitched and aerated on the first brew only. Never had a problem with growth or off-flavors using this method. I aerate at 2 LPM with oxygen for the whole 30-35 min. cool-in, this is an 11-12 Bbl. batch size. Wyeast has a little book on yeast management, and I think White Labs has a similar on-line guide as well, either one can be pretty handy for yeast management issues, and basic labwork protocols. Good Luck!

[gitchegumee]

Agree. First batch only.

[liammckenna]

Personally, I like to do it for the first five minutes of second batch cool-in.

Find I get better eight hour yeast counts, cleaner fermentations, less cropping issues.

Pax.

Liam

[Michael Murphy]

only the first batch, occasionally when Im creating a Barley wine Ill hit it a little on the second batch or if Im trying to propagate from smaller yeast pitches.

[Fred Scheer]

aeration double batch

HI Guys:

We all know that oxygen is one of the major factors which negativly affect the taste stability. I their article: effects of different techniques in pitching technology,,, the authors from the University of Munich, Germany, recommend to reducing aeration or by NOT aerating the last brew, fermentation activity could be maintained while simultaneously exerting a positive influence on SO2 formation and on aging stability of the beers.

Cheers

Fred

[BigWilley]

I will second the first batch only practice, as I used to brew and oxygenate both batches on consequtive brew days. Since I switched to first batch only I have had no issues. I cant say that oxygenating both batches hurt but I was definately wasting O2 and probably getting more yeast growth than neccesary.

[jsvoboda]

You never want to add O2 if you have 50% attenuation already acived. My double batchs are only oxygenated on the first knock out. There's plenty O2 man. Don't worry.

[danlow35]

I am an assisant brewer at a microbrewery in Canada, and my head brewer has a slightly different approach. We do a double batch on the same day, 2 shifts. We do not oxiginate the first brew nor do we send it into the fermenter with the yeast. It is only the second brew that gets the oxygen and the yeast. By the following morning, the beer is fermenting like crazy and we have no problems as far as odd flavors or tastes, nor do we get any infections. just another way of doing things I guess.

dan

[Michael Murphy]

I am an assisant brewer at a microbrewery in Canada, and my head brewer has a slightly different approach. We do a double batch on the same day, 2 shifts. We do not oxiginate the first brew nor do we send it into the fermenter with the yeast. It is only the second brew that gets the oxygen and the yeast. By the following morning, the beer is fermenting like crazy and we have no problems as far as odd flavors or tastes, nor do we get any infections. just another way of doing things I guess.

dan

he probably does that to get to the correct pitching temp. I cant see any other benefit other than that... or he is too busy durring the first brew to mess around with a yeast harvest.

[bryguy215]

our technique is to oxygenate the first half of the brews going into an already pitched fermenter. If we are putting 5 brews in one fermenter we will oxygenate the first two and a half brews while cooling-in. Works great

[Larry Horwitz]

this is the classic "chicken or egg" question. The short answer is get all of you wort in in 12 hours....but that's just not realty for most of us. There are several great papers on this as well as a talk by michael Lewis with a transcript somewhere from the BA convention last year. Look for his stuff or email him for a copy.

[Airidini]

O2 in wort

If I remember correctly in De Clercks- A Text Book To Brewing he wrote that wort can be doubly aerated as long as it is performed within a 12 hour period from the onset the first batch pitched. At any rate I use this method with open top fermenters and an explosion of yeast growth does occurs which is cropped off for the next two batches. Therefore, fresh vibrant young daughter cells are collected and ready to go to work. I have yet had an adverse effect with method as I had learned this process while working in Europe. Often enough if your methodology of sanitation is in good practice you can repitch many many times before needing to wash or clean-up the yeast.

[dick murton]

At the end of the day, you do what the yeast and beer flavour demands. If the yeast ferments OK when uyou only aerate teh first brew, and the yest is healthy enough to repitch, and the beer tastes good - then you only need to aerate the first batch.

If the yeast doesn't ferment out properly, is slow, or is not good enough to re-use for pitching, then try aerating the second batch and subsequent batches as well. Differnt yeast behave differently. There is no simple answer, except always aerate and pitch into the first batch. Bacteria grow faster than yeast, and can cause nasty off flavours (think butyric - baby sick !!) in unpitched wort very rapidly