Oxygenating wort before adding yeast

[trustyrusty]

Oxygenating - seems like a big word for this time of the morning

Reading something about this - and it seems to be quite important, I think it was a John Palmer article.
He says that pouring liquid into bucket or FV with a splash does not give enough oxygen pre yeast addition - and even talks about using an oxygen bottle. I have watched a few videos from breweries, home brewers etc, never really seen this or was it talked about this.

I normally fill the FV with a short hose that has rose on it that is making bubbles the whole fill, but I guess the health of the yeast is important in the first few days, so I wonder if this crucial.

I suppose if you were trying to make the perfect award winning beer, but would this make a huge difference?

Has anyone got any distinctively different results from doing both ways. I would suspect you would have to be an award winning judge to tell the difference.

cheers

 

[Lethaldog]

I've always filled my fermenters straight out of the brew kettle tap ( no hose) then pitch yeast and that seems to work for me but in saying that I don't have an air stone and have never done it any other way to compare, I always get a nice healthy kick off !

Edit: I also use a strainer on top of fermenter just in case anything gets through the hop screen, not sure if this helps aerate or not!

 

[dteahan]

I have seen a decent impact on both attenuation and time to complete fermentation when I moved to pure O2.

I have not repeated two of the same recipes before and after to compare the taste difference between pure O2 and normal methods but on reading the various literature a good amount of oxygen is required to by yeast to support healthy cell walls and reproduction (rather than yeast needing it to "breathe").

 

[Lyrebird_Cycles]

Aerating at pitch temp is generally not very effective because the equilibrium concentration is fairly low and because the nitrogen tends to re-strip some of the oxygen. Using O2 avoids this, plus you can measure it to ensure you achieve the desired DO2 level in one hit.

The optimal DO2 level varies with style and fermentation temperature: 8ppm is enough for a standard ale fermented at 18 oC, you'd want maybe double that for a strong Belgian fermented warm. You won't achieve the higher figures with a single shot aeration.

That being said, that's mostly a problem at commercial scale where you don't want the re-work. At small scale you can simply re-aerate at say 12 hour intervals during the growth phase.

I've done direct trials in yeast propagators comparing oxygenation vs aeration (and inadverently vs neither when some clown turned the air off). Oxygenation is far more effective.

 

[Judanero]

My beers have better attenuation since moving to O2 and I perceive them to be a cleaner ferment taste wise.

It was also at the same time that I began to focus more on yeast health and pitching rates and ferment temperature practices so it may be a combination of all.

I fill my fv's via a large funnel with a couple holes drilled through the spout so it breaks the wort up nicely, there is a lot of foam already and then I give the wort ~40-60 secs of 02.

Breweries employ a few methods to oxygenate their wort but iirc a great deal of it is done inline either with filtered pressurised air or pure 02, and yes yeast health is very important in the first 48hrs or so.

 

[Lyrebird_Cycles]

A technique I have used on a small scale that you might find useful:

Set up your oxygenation rig ( in my case a size D oxy bottle, a sterile filter and a stainless sinter).

Get a bucket full of water and a large plastic measuring cylinder or jug that fits in the bucket. Submerge the jug or cylinder and turn it upside down.

Whilst it is submerged get the oxygen flowing and then place the sinter under the jug or cylinder so all the oxygen flows up into it. As it fills with oxygen lift it up so the water lines inside and out stay roughly level: this ensures you are measuring at near enough to STP.

Time how long it takes to fill the jug and divide volume by time to give volumetric flow rate. Multiply by 1.55 to get mass flow rate.

Nanny warning: Do not smoke while you are doing this (although it's quite fun to watch what happens when you drop a lit cigarette into pure oxygen).

 

[Alex.Tas]

Breweries employ a few methods to oxygenate their wort but iirc a great deal of it is done inline either with filtered pressurised air or pure 02, and yes yeast health is very important in the first 48hrs or so.

Here is one such system at a local brewery.


wort from the plate chiller going into FV, inline O2 and yeast addition.