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-   -   Oxygenating at the 14th Hour (http://www.homebrewtalk.com/f13/oxygenating-14th-hour-22064/)

onecolumbyte 02-13-2007 05:44 PM

Oxygenating at the 14th Hour
 
There's been a lot of discussion on whether and how to oxygenate your wort. The thread on definitive oxygenation experiment was quite a noble attempt to settle it. While doing a little research I ran across the following on the lallemand website. They produce dry yeast specfically nottingham and windsor. see lallemand.com. In response to a question by Marc Sedam on high alcohol worts Dr. Cone responded "Most ale yeast can easily ferment up to 12% abv as long as it is healthy and happy. The pH of wort (4.0+) is optimum for this level of alcohol production...You must have 30+ ppm dissolved Oxygen. The best time to begin adding the Oxygen is around the 14th hour when the yeast is hungriest for the O2. If all the O2 is added at the beginning, a substantial amount of it will be wasted. There is nothing sacred about the 14th. hour. The O2 should be introduced before the yeast reaches the stationary phase. The O2 is necessary for the yeast to produce lipids which act as a growth factor in the first stage of the fermentation and protect the yeast against the alcohol toxicity near the end of the fermentation. The yeast will probably require much more nutrients than are normally found in wort. You should consider adding about 1 gram Fermaid K and 2 - 4 grams Diammonium phosphate / gallon of wort. The Fermaid should be added with the yeast and the DAP should be added in increments over the first half of the fermentation. There should be no pressure build up. Saturation and CO2 supersaturation can be toxic. Frequent stirring minimizes this.

As a homebrewer should I add oxygen at/around the 14th hour? What about yeast nutrients and CO2 buildup? What do you all think about this?

aseelye 02-13-2007 06:14 PM

Well, I use nottingham myself, though in a reply to a question I posed to them, those recommendations were for 12%+ ABV batches. In your standard 6-8% homebrew, I've had fantastic results with oxygenating at pitch time and throwing some nutrient in. I usually whip up a 2-3 quart starter a couple days before hand, but that's not really mandatory, though last time I did, I had a 5.5% porter running about 2 bubbles/sec at 68 degrees.

Cheesefood 02-13-2007 07:19 PM

Wyeast agrees:

Quote:

Originally Posted by Wyeast Lab's Website
Aeration is difficult for homebrewers. One good method is to fill a carboy about 1/2 full of cooled wort. Close and shake vigorously for a couple of minutes. This will supplied dissloved oxygen which is necessary for yeast metabolism. Pitch the yeast and fill the carboy the rest of the way. Using an areation stone is also an effective way to add oxygen, by using an aquarium pump with a sterile filter. These items are often available at home brewing stores. Adding oxygen the following day after brewing, by rousing with a sanitary spoon or wire whip is also beneficial.


onecolumbyte 02-13-2007 08:24 PM

Quote:

Originally Posted by Cheesefood
Wyeast agrees:

I've been wondering about the aquirium pump as well. What amount of filtration would be required to actually filter out a one celled organism like wild yeast. I realize that MANY MANY people have good results this way, and that's good enough for me. But the filters they use don't actually manage to filter out wild yeasts do they?

FlyGuy 02-13-2007 08:44 PM

Quote:

Originally Posted by onecolumbyte
I've been wondering about the aquirium pump as well. What amount of filtration would be required to actually filter out a one celled organism like wild yeast. I realize that MANY MANY people have good results this way, and that's good enough for me. But the filters they use don't actually manage to filter out wild yeasts do they?

Yep, a HEPA filter will filter out bacterium-sized organisms (which are smaller than yeast cells/spores). They are cheap, too:

http://pivo.northernbrewer.com/nbsto...7861&x=29&y=11

david_42 02-14-2007 01:53 AM

I've done multiple aerations for high gravity ales. I use a pump, filter and stone. By plugging the pump into a timer, I can aerate every two hours without foaming over or having to check the bucket.

Ol' Grog 02-14-2007 02:00 PM

I suppose if you wanted to create a 12% brew, that would be the way to go. Must of us are pretty happy with our 3-7% brews. I'd be afraid of accidently contaminating the batch when going back and aerating after pitching.


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