Oxygenation Poll

[eastoak]

There is O2 in the "little red" canister when you buy it for $5-8. They are not meant to be reused. They are light as it is very little gas inside, but they are good for several batches of oxygenation.

thanks.

 

[Zamial]

The following is cut and pasted from Wyeast. Direct link: http://www.wyeastlab.com/hb_oxygenation.cfm

Oxygenation

Oxygen is a critical additive in brewing. Oxygen is the only necessary nutrient not naturally found in wort. Adding adequate oxygen to wort requires a fundamental understanding of why yeast need oxygen, how much oxygen they need, and how to get oxygen into solution and the factors affecting solubility of oxygen.
Why Yeast Need Oxygen

Yeast use oxygen for cell membrane synthesis. Without oxygen, cell growth will be extremely limited. Yeast can only produce sterols and certain unsaturated fatty acids necessary for cell growth in the presence of oxygen.

Inadequate oxygenation will lead to inadequate yeast growth. Inadequate yeast growth can cause poor attenuation, inconsistent or long fermentations, production of undesirable flavor and aroma compounds, and produces yeast that are not fit for harvesting and re-pitching.

How Much Oxygen?

Oxygen requirement is variable depending on: yeast strain employed, original gravity of wort, and wort trub levels.

Some yeast strains have higher oxygen requirements than others. It is generally safe to assume that you need at least 10ppm of oxygen. 10ppm will supply adequate oxygen in most situations. Over-oxygenation is generally not a concern as the yeast will use all available oxygen within 3 to 9 hours of pitching and oxygen will come out of solution during that time as well. Under-oxygenation is a much bigger concern.

High original gravity (>1.065) wort, in addition to increasing osmotic stress on yeast, can cause problems with achieving adequate levels of dissolved oxygen. As the gravity of wort increases, solubility of oxygen decreases. Increased temperatures also decrease the solubility of wort.

The unsaturated fatty acids found in wort trub can be utilized by yeast for membrane synthesis. If wort trub levels are low, yeast will need to synthesize more of these lipids and therefore will require more oxygen.

Methods of Aeration / Oxygenation

Homebrewers have several aeration/oxygenation methods available to them: siphon sprays, whipping, splashing, shaking, pumping air through a stone with an aquarium pump, and injecting pure oxygen through a sintered stone. We have tested all of these methods using a dissolved oxygen meter and have found that, when using air, 8 ppm of oxygen in solution is the best that you can achieve. Injecting oxygen through a stone will allow much higher dissolved oxygen levels. The chart below shows methods tested and the results.


Method DO ppm Time
Siphon Spray 4 ppm 0 sec.
Splashing & Shaking 8 ppm 40 sec.
Aquarium Pump w/ stone 8 ppm 5 min
Pure Oxygen w/ stone 0-26ppm 60 sec (12ppm)

It was concluded that pumping compressed air through a stone is not an efficient way to provide adequate levels of DO. Traditional splashing and shaking, although laborious, is fairly efficient at dissolving up to 8 ppm oxygen. To increase levels of oxygen, the carboy headspace can be purged with pure oxygen prior to shaking. The easiest and most effective method remains injecting pure oxygen through a scintered stone.

The morale of the story: If you are going to buy anything for aeration you may as well just spend up for the O2 or just keep on shaking it.

 

[Golddiggie]

Why do you say you need to leave the regulator connected? I have not found that to be the case whatsoever and I believe the Benzomatic canister label even mentions removing regulators and replacing the protective cap when not in service.

And just confirming that the tanks seem to last damn near forever... 20-30 batches is probably about right.

I've just always left those canisters connected. But, that was when it was part of a welding system. If the canister will seal up again if you remove the regulator, like a propane torch will, then it's all good to remove it (probably better too)...

I was thinking they were more like the paintball gun CO2 canisters, or the small CO2 cartridges... Thinking about it more, and looking back, I can see how you would be able to remove the regulator from them without issue, provided they are designed that way... I guess I'll find out pretty soon, since I might be picking one up later today...

 

[Montanaandy]

You will wear down the threads if you disconnect it each time after use. I just leave mine attached and clean and sanitize it so it is ready for the next batch.

 

[njnear76]

Oxygenation is pretty important step. If you are going to shake. Shake a lot. I would say pour back and forth 10-20 times. This is obviously hellish on the back.

I've had good luck with siphoning my wort and employing a venturi tube. The only drawback is that it can take quite awhile to transfer the wort, since the siphon loses suction occasionally.

The venturi tube has worked well for me though. It takes usually 2-3 days before I see those lovely fermentation bubbles. Although that used to worry me a bit, I think it is a sign that there is enough oxygen in there.

Brief Edit:
The 2-3 days probably has a lot to do with my fermentation temperatures. I ferment my ales typically at 55-60F and in a water bath to boot. A lot of CO2 can be absorbed at that temperature. Not to mention that slows the yeast a little bit.

 

[Golddiggie]

I usually have active fermentation sign within 12-18 hours of pitching the yeast... That's been using the auto-siphon (before installing the ball valve in my kettle) with even shorter delays since getting the wort into the primary via the ball valve.

It's going to be interesting to see what introducing pure O2 into the wort does...

 

[ayoungrad]

I'm close to trying one out myself...

 

[MNDan]

A key point that isn't mentioned in the Wyeast info:


Some British brewers "drop" their fermenting wort up to a day after adding yeast. How effective is this for adding oxygen? And how late can wort be oxygenated?

Response from Dr. Clayton Cone:
The optimum time to add oxygen to the fermentation is about 12 - 24 hours into the fermentation.. Active Dry Beer Yeast(does) and re-pitched yeast (usually) have enough lipids for two to three generations. It is at that time the budding yeast can most efficiently use the oxygen to continue to bud and also produce enough lipids to protect itself against the higher levels of alcohol. This is especially true with high gravity brewing.

 

[Montanaandy]

Some say boiling is good for cleaning. And I'm under the impression that positive pressure on the stone prior to putting it into any liquid keeps the liquid on the exterior and out of the pores. The only time I don't pressurize the stone is when I soak it in a bucket of starsan. I start the O2 before I remove the wand from the sanitizer and submerge the stone in the wort. I keep the 02 flowing while I rinse in hot water. Rinse, repeat. So far so good.

We have always put the stone + tube in a bucket of hot sudsy water and open it up for a couple of seconds. Rinse it off and then do the same thing in a solution of Star San. Clean. Never have had an infection.

 

[GodsStepBrother]

I just ordered the oxygen kit, so I can see the difference.

 

[thebeers54]

I just got my williams kit in today.. I wish I could have used it on the oatmeal stout I brewed last night but the yeast already kicked off and I haven't bought the o2 tank yet. I am looking forward to tasting the difference. I haven't heard of anyone who oxygenates and doesn't think their beer improved and that's good enough for me.

 

[ChickenHops]

I just ordered the oxygen kit, so I can see the difference.

I bought a kit in January and started using the small red O2 bottles to oxygenate. After the first batch I was impressed. After the second, third and fourth I was sold. My apparent attenuation has improved.

In the past I used the vigorous stirring method. Using O2 is also a lot easier than stirring. I have a large commercial SS whisk. I used to whip up the wort for at 5 minutes, or longer for high gravity. Now 60 seconds of holding a SS tube with a stone on the end and I'm done.

I particularly like the fact that I'm not introducing as much air from my brewing space -- which certainly has grain dust -- into the wort with my new method. Not that I had a problem with infections before.

I ferment and oxygenate in buckets. I keep the lid almost closed as I oxygenate, and I seal it the moment I remove the wand/stone. The airspace in the bucket still has a lot of O2. I shake the bucket some more as I move it to where ever it's going to ferment.

I don't know where my O2 levels end up, but I'm convinced they're higher than with stirring alone. I can't attribute my higher AA to anything other than going to O2.

 

[ayoungrad]

I'm cautiously optimistic about the O2. But I'm definitely not expected any change in my apparent attenuation.

I just bottled a 1.098 OG IIPA that came in at 10.5% ABV and an AA of 80% with US05.

I think that will be tough to beat.

 

[ChickenHops]

I'm cautiously optimistic about the O2. But I'm definitely not expected any change in my apparent attenuation.

I just bottled a 1.098 OG IIPA that came in at 10.5% ABV and an AA of 80% with US05.

I think that will be tough to beat.

I only use liquid yeast. I don't know if O2 would make that much difference with dry yeast. My AA went from being in the middle range to the high range of the manufacturer's attenuation range. But again, it was liquid.

How big was the batch if IIPA, and how many packets of US05 did you pitch? That's pretty impressive. The last time I used dry yeast was last fall on an IIPA.

 

[ayoungrad]

I was wondering about that re: dry yeast vs. liquid yeast. I use US05 for everything except batches that need specific yeasts.

It was originally a 5.5 gallon batch for which I bottled about 4.3 gallons (TONS of trub and over 10 ounces of hop pellets (4 just for dry hopping)). I rehydrated two 11.5g packets. Then got anxious. My goal OG had been 1.082 but I had changed a few things that increased efficiency by leaps and bounds - that's how I got the 1.098 - so I also sprinkled a third packet on the wort once it was in the fermenter. Kind of overkill but still less than $15 total for the yeast and you can't argue with the results...

 

[Pilgarlic]

If you pour over the Lallemand site you'll find conflicting information. You'll find statements like "aeration isn't necessary for dry yeasts, though it won't do any harm", and you'll find other FAQs that suggest that oxygenation will help. I'm out on this one. For a year, based on info from the Lallemand site, I pitched the reydrated dry yeast without aerating and got great results. Since, I've been using liquid yeasts.