mxyzptlk

Recipes 

it is an aquarium stone. I wasn't aware they made stones specifically for brewing. Are they a lot more expensive? I just bought 4 air stones for a buck something. Even if I treat them as disposable, it's still pretty cheap. Are there any advantages to stainless steel stones other than durability?

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Secondary 2: 2006 Barleywine

Secondary 1: New Year's Day

Bottled: Schmohz Contest Brew, Goodwill Towards Man

http://www.geocities.com/danvkooi

El Pistolero

Recipes 

I think the stainless stones have much smaller pores than aquarium stones, meaning finer air bubbles, meaning better absorption by the wort. Yes, they are more expensive...$25 bucks or so for a big one I think, tho it should last a lifetime.

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[/I] Up Next - Hobgoblin
After That - Czech Pilsner
Primary - Humboldt Hop Rod (4/24)
Primary - NOT Wheat AG SNCA (5/5)
Secondary -
Conditioning - SNCA Clone (3/3),

Kaiser

Recipes 

El P, Scott,

how long do you oxygenate you wort? I just got one of these ogygenation systems that you use with the $8 O2 bottle from Lowes/Home Depot and I had it in there for 15min. But I only went for small bubbles (hardly any foam). The instructions said one minute but that seemed a little short to me for 5gal worth of wort.

Kai

El Pistolero

Recipes 

Here's the instructions that came with mine:

OG: 1.040-1.050, 1 minute
OG: 1.050-1.060, 1.5 minute
OG: 1.060-1.070, 2 minutes
OG: 1.070 plus, 2.5-3 minutes and once additionally in 12-14 hours

These schedules should yield 10-15ppm dissolved oxygen.

I also oxygenate my starters for 10 seconds once per hour for the first 4-8 hours.

__________________
[/I] Up Next - Hobgoblin
After That - Czech Pilsner
Primary - Humboldt Hop Rod (4/24)
Primary - NOT Wheat AG SNCA (5/5)
Secondary -
Conditioning - SNCA Clone (3/3),

Kaiser

Recipes 

Thanks,

I think I have the same one.
Does the last line mean, that onlt 1.070+ worts need to get an additional oxygenation or should every type of wort get a second dose.

Kai

El Pistolero

Recipes 

I took it to mean only 1.070+ gets a second shot at 12 hours. I did this on a wee heavy, and it went ballistic within an hour after the second oxygenation.

__________________
[/I] Up Next - Hobgoblin
After That - Czech Pilsner
Primary - Humboldt Hop Rod (4/24)
Primary - NOT Wheat AG SNCA (5/5)
Secondary -
Conditioning - SNCA Clone (3/3),

DrewsBrews

Recipes 

15 minutes... holy carp! Might be time to go get another O2 tank already. I think the info in my kit said total yield is something like 20 batches averaging 60 seconds per batch.

I used mine on a porter two weeks ago. The SG was 1080, but I didn't have the handy chart El P posted so I only ran it for a little over a minute. Even at that, the fermentation was complete by around the 11th day. I racked it into a keg last night and the FG was 1020 - roughly 8% ABV (after temp corrections) by my calcs. Not bad, considering I never shook the thing at all. Probably one of the best purchases I've made. I'm trying to talk my friends into buying them, too.

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So long, and thanks for all the beer...

Tap 1: Mac n Jack amber clone
Tap 2: Zippo
Tap 3: Nada
Bottles: Dust

Kaiser

Recipes 

For some reason I had this number in the back of my head.

The batch took some time to take off. Maybe the yeast did a lot of growing (I hope this will not be detrimental to the flavor). It ferments so heavily that it lifts up trub and pushes it through the blow-off tube. Thank godness I installed one that is as wide as the carboy opening.

I did 1.5 min on my Maerzen tonight. I'll see how well this one starts.

Yesterday I read (I think it was even in a link you posted) that the later addition of some oxygen is useful to boost another growth spurt. That's why it is not as obvious to me. I'f I don't see any signs of fermentation by tomorrow morning I'll give it another shot.

Kai

Kaiser

Recipes 

So, I did the math. I had to, I'm an engineer .

When I oxygenated (only small bubbles) I saw little bubbles travel up the oxygen hose. These bubbles were from sanitizing solution that I used to back-flush the hose and stone.

Based on the speed of the bubbles in the hose and the diameter of the hose I determined that the wort gets about 3.3ml of oxygen/second. With an oxygenation time of 90s there will be 300ml of Oxygen pumped into the wort.

Using the specific weight of Oxygen (1.42 g/l at 1.035 mbar and 20C), I get 0.42g of O2 into the wort.If all this would be absobed, I would get a concentration of 20 mg/l (same as ppm).

The big unknown is the absoption factor. I didn't measure how much air/O2 came out of the carboy. But assuming an absoption factor of 0.5 would get me the desired 10g/l.

And yes, 15min is definetely to long. Unless the absorption factor is 0.05.

bleppek

Recipes 

The oxygen system I purchased from Northern Brewer suggested that it be used for 15-20 minutes. This kit uses an aquarium pump and not pure O2. Assuming that "normal" air is about 20% O2, this would lead me to believe that a pure O2 system should be used for 20% of 15-20 min (3-5 minutes), which is close to what El P mentioned above.
Are there any dangers of over-oxygenating other than a waste of O2?

These are just my late night thoughts, as I sit at work with nothing to do but read about beer(gotta love the overnight shifts).