Oxygenating "Big Beers" with Pure O2 in wort

[Ciderhead]

Ok so I am thinking I need 60 secs at 1L/min for avg wort, 1040-1060 and 90-120secs for big beers which I rarely do.

I am now reading "when oxygenating a higher-gravity wort, you need higher oxygen levels - roughly proportionate to the amount of yeast. However, it's usually recommended to reoxygenate after the yeast have time for a cell division, This will result in a cleaner-flavored beer. Obviously, if you want your beer to have more off-flavors (specifically acetaldehyde and diacetyl), then a second dose of oxygen is counter productive"

I am thinking or re-inject another RIS I have to do, anybody any thoughts as to an optimum time to do that? How long does initial cell division take?

[Ciderhead]

I think I found the answer

When about aerating really high-gravity beers? It's simply stated in "Yeast" that with beers with OGs higher than 1.092, aeration methods other than pure oxygen simply won't do. For all beers with an OG above 1.083, aerate TWICE. That is, before pitching the yeast, and then another dose of oxygen 12 to 18 hours after pitching (this allows the yeast one cell division). This second dose was shown in a study to help speed up fermentation speed and attenuation.

Anybody any thoughts?

[christhebrewer]

Makes perfect sense to my. I can't think of a reason not to re-oxygenate. Is it a good idea for a starter too?

[Tom]

I read 'Yeast' by the whitelabs boys too. 12-18hrs in add another dose of oxygen. I don't have an oxygen stone, so I was going to do it with gravity. It's not ideal (the book has a chart on this kind of thing, and agitation aeration is piss-poor compared to an oxygen stone) but it's better than nothing.

Unless you like acetaldehyde or diacetyl, of course.

I wonder how many barrel-RIS brewers did the 12hr oxygen thing?

[christhebrewer]

this is the oxygen stone I got.
http://www.ebay.ie/itm/280866354728?var=580089020402&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

[Ciderhead]

Get yourself down to your local aquarium suppliers, one of their aeration stones is better than nothing
Just doing the Wicklow top up ris with recirculating mash and it will get 2 shots of O2, one 90 sec burst pre yeast and a second 12 hours later
Ill be like a b.llox if if doesn't kick off at 90mph and fully finish out as expected ha ha


TT

[Eoin]

Isn't this effectively 'double dropping'? At least I think that's what the Brits call it.

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[Ciderhead]

? Never heard of that before, well not in relation to beer anyways :-)


TT

[Eoin]

Look up Marstons double drop. The beer gets dropped into a second vessel 12 hours in.

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[Ciderhead]

90mph
In 5 years of brewing never had one take off so fast, on the left in the carboy at 6 last night with 1 Litre starter, other one RIS with 2 litre, 5 hours later.
Only difference was the 02

I suspect they are gonna blow





TT

[Ciderhead]

Isn't this effectively 'double dropping'? At least I think that's what the Brits call it.

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Well I didn't know that, sounds kind of like an aggressive early secondary.


Double dropping, also known as the dropping system is a brewing method used for the production of ales. During the early 20th century it was the most popular method of clearing trub (inactive yeast and excess, staling and haze-forming protein from the malted barley) during fermentation for English ales. It is less commonly used today as it requires additional brewing vessels in a 2-tier system.[16]

During the double dropping process the wort (newly brewed, fermenting beer) is first fermented for a period of time before being transferred, under gravity or by other means, into a lower vessel where it continues fermentation. The dropping process has two primary effects on the beer being fermented: the trub that has settled during the first period of fermentation will be left behind, leaving a cleaner beer and a cleaner yeast to crop from the beer for the next fermentation; the second effect is the aeration of the wort, which results in healthy clean yeast growth, and in certain circumstances butterscotch flavours from the production of diacetyl.[17][18]

Breweries using the double dropping process include Wychwood Brewery who contract brew Brakspear branded beers,[17] and Flack Manor.[19] Marston's use the name Double Drop for one of their beers as they use the related brewing method of the Burton Union system.[20] Wychwood transfers the wort the morning after the day fermentation started - typically about 16 hours later. This process originally took place at the Brakspear brewery in Henley. When Brakspear moved to the Refresh UK's brewery in Witney, a new brewery was built to include the original double dropping system.[21] Brakspear claim that some of the flavour common to its beer is due to a combination of its very old complex multi-strain yeast and the dropping method which encourages it to produce the butterscotch-flavoured compound diacetyl.

[Eoin]

Ok so double drop without taking it off the yeast and trub.

Not a secondary per se.

[Ciderhead]

Huh?
"the trub that has settled during the first period of fermentation will be left behind"

[Hop Bomb]

Is the beer on the left WLP007 by any chance?

[Eoin]

Huh?
"the trub that has settled during the first period of fermentation will be left behind"

Read mine in reverse to what you have read. I phrased it very badly.