I knew Aeration Equipment is a Waste of $...

[Bobby_M]

Bobby_M, you aerate with O2/stone; do you use both dry/liquid yeast? The reason I ask is because I just put the wort in the carboy (intentionally creating a lot of agitation) and shake the carboy. I think most of my aeration occurs just getting wort into the carboy. So regardless of whether I use dry/liquid yeast, I think the amount of DO is about the same.

BUT...the yeast cake from similar worts when using dry yeast always seems significantly bigger than when using liquid in my brews (just eyeballing it). Is that the case in your brews? Anybody else notice this? IIRC, in most cases the major 'constraint' to final cell mass is O2 (and/or associated 'nutrients' from it). If this is all true, then could it be a sign that one is not really getting proper DO levels for liquid yeast? Or is it that perhaps the dry yeast is actually over-multiplying because it already has all the nutrients it needs...and then we add O2 on top of that?

The difference in yeast cake size between dry/liquid just seems like it's screaming to me that in at least one case, I'm not pitching the right amount or not aerating properly. And I always try to pitch the right amount.

RE: that experiment; I don't really trust anything quantitative from it but I think qualitatively it at least had something to offer.

I think it's difficult to use yeast cake appearance as a real indicator of the actual cell count because it can be affected by all the other break material and hop trub. It may also be the case that dry yeast is already such a large colony compared to liquid and of course the latter is affected by whether you make a starter, step it up, age of the yeast, etc. Many brewers try getting away with just pitching a vial/smack pack and in those cases, I'd be much more prone to recommending getting the O2 over the ambient saturation of 8ppm because you're basically making a big starter and fermenting a batch of beer at the same time.

Since you asked what I do;

If my wort is an ale at 1.060 or less, I run O2 into the wort for 60 seconds @ .25 lpm. If it's a dry yeast, I just pitch it dry. If it's liquid yeast, I make a 1 liter starter.

If the ale wort is over 1.060, I still O2 the same way but dry yeast gets rehydrated first or I'll make a 2 liter starter with liquid.

If it's a lager, O2 the same but I step the starter up 1 liter, cold crash and decant, 2 liter, cold crash, decant and pitch only the slurry.

 

[springer]

I may be a pretty big guy but there is no way in hell I am shaking 10 gallons of beer . I just use the o2 when I pitch liquid and always use a starter . With dry I do let it aerate by letting it run into the carboy from above the neck it does aerate to an extent also carrying the carboy from the garage to the basement it sloshes around quite a bit I also always rehydrate the dry yeast I don't pitch it dry. I like to see the yeast bloom before I pitch, got into that habit when the Notty was questionable

 

[Bobby_M]

I hear you. I hate CARRYING a carboy, nevermind shaking it.

Something else I thought of was that you could flood the headspace with pure O2 and shake the carboy to have it done in 5 seconds, but now that's getting ridiculous.

 

[springer]

I only carry when i split the batch all other times I use either a sanke keg or a 15 gallon Dulex container and a hand truck.

 

[SpanishCastleAle]

I think it's difficult to use yeast cake appearance as a real indicator of the actual cell count because it can be affected by all the other break material and hop trub. It may also be the case that dry yeast is already such a large colony compared to liquid and of course the latter is affected by whether you make a starter, step it up, age of the yeast, etc. Many brewers try getting away with just pitching a vial/smack pack and in those cases, I'd be much more prone to recommending getting the O2 over the ambient saturation of 8ppm because you're basically making a big starter and fermenting a batch of beer at the same time.

Yea, it's just eyeballing it but these are fairly similar worts. And the assumption was 'proper pitching rates' (per Mr Malty anyway). I never even noticed it until I washed some dry yeast and the difference was pretty noticeable, this after washing liquid yeast many, many times.

I'll soon be trying 10 gal batches split into two carboys and will expect to often be using dry yeast in one. Maybe I can test it further.

 

[2-0turbo]

You know, this has bothered me since I got into brewing. Those of you who say that the study is flawed, I'm not sure what you believe. The guys checks oxygen saturation with a meter and many of you are saying that "you get more O2 dissolved with your setups." Which, I don't believe.

You guys ever seen water treatment plants where they are spraying the waste water up into the air? Any ideas on why they're doing that? To oxygenate the waste and let the aerobic bacteria do their job. If blowing oxygen through the waste or blowing air was more effective, why wouldn't they do that? Because pure oxygen (O2) is not soluble in water, which is why I've been so skeptical about "bubbling" oxygen through your wort. You not putting any O2 into solution in the wort unless it is only from turning over the fluid and exposing it to more air.

The reason that O2 won't dissolve in water is because it is non-polar and water is polar. Please understand that I'm not saying oxygen is not soluble in water. Pure oxygen never hangs out as just "O", it always pairs up and hangs out with other Oxygen molecules. Consequently, it is O2. But, in air (which is a mixture of many gases, chiefly nitrogen), you can get some free 'O' molecules. Which is why you do get some dissolved oxygen in water--but it because it is in a mixture of air (mostly nitrogen).

Conversely, CO2, which we all know as carbonating gas, is non-polar. It is very soluble in water. When you crank the pressure on your corney, you can HEAR the gas rushing into and going into solution. Want 5 volumes of CO2 in your beer? Crank up the pressure. If you tried the same experiment with pure oxygen, you would get nothing.

It has been a long time since college chemistry, so I might have a couple details wrong here. See this link to play around and see how some molecules are polar and some are non-polar. You can also google a ton of things (molecules) and figure out if they're polar or non-polar. Just one last example to "prove" to you this works. Say you have some rust stains on your bathtub. Rust is Iron oxide, FeO2. I can tell you what would remove the stains without ever trying because you know that FeO2 is polar. Will methanol remove rust stains? No. Because iron oxide and alcohols are both polar. (in fact, all alcohols are polar, so you don't need to try any others) What about carbon tetrachloride? Absolutely. If you have some carbon tetrachloride (which is non-polar), it will easily remove rust stains because Iron Oxide is soluble in Carbon tetrachloride.

This is a complicated topic, but rest assured, pure oxygen is not soluble in water (or wort). If you don't believe me, put some wort into a corny and put 30 psi of O2 on it. You won't see any flow (or very, very little). You're better off pouring your wort between two containers and doing a lot of splashing. Happy brewing guys.

 

[Bobby_M]

So every pro brewery on earth that injects O2 inline post chiller is wasting money.

Wyeast tested yeast growth for various O2 saturation levels:

DO ppm # Doublings
2ppm 1.2
9ppm 1.5
15ppm 1.62
21 ppm 1.66
26 ppm 1.70

If you can't get O2 to supersaturate in wort, how did they measure up to 26ppm?


Method DO ppm Time
Syphon 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

 

[Synovia]

So every pro brewery on earth that injects O2 inline post chiller is wasting money.

It wouldn't be the first time big business was wasting tons of money simply because that's the way its always been done.

Suggesting that it must be helpful because they wouldn't do it otherwise is just an appeal to authority.

 

[BioBeing]

You know, this has bothered me since I got into brewing. Those of you who say that the study is flawed, I'm not sure what you believe. The guys checks oxygen saturation with a meter and many of you are saying that "you get more O2 dissolved with your setups." Which, I don't believe.

They measure saturation as the percent of the maximum that you get by shaking water in air. This is their 100% point. Which works out to be about 8 ppm. By using pure oxygen gas you can up to 26 ppm in the liquid. That would be equivalent to 325% saturation on their scale. If you want rapid growth of healthy yeast, ~ 21 ppm is what you want to shoot for (according to wyeast; style dependent).

You just can't get 21 ppm oxygen in wort by shaking alone.

You guys ever seen water treatment plants where they are spraying the waste water up into the air? Any ideas on why they're doing that? To oxygenate the waste and let the aerobic bacteria do their job. If blowing oxygen through the waste or blowing air was more effective, why wouldn't they do that?

Because, maybe, in that case, the level of aeration they get is sufficient? It is cheaper, easier and safer to just spray the liquid rather than to need pure O2.

Because pure oxygen (O2) is not soluble in water, which is why I've been so skeptical about "bubbling" oxygen through your wort. You not putting any O2 into solution in the wort unless it is only from turning over the fluid and exposing it to more air.

Which is why we use a .2 micron stone to make tiny bubbles. Increased surface area means more efficient transfer.

And O2 is not very soluble in water. It is not completely insoluble (or fish wouldn't live).

The reason that O2 won't dissolve in water is because it is non-polar and water is polar. Please understand that I'm not saying oxygen is not soluble in water. Pure oxygen never hangs out as just "O", it always pairs up and hangs out with other Oxygen molecules. Consequently, it is O2. But, in air (which is a mixture of many gases, chiefly nitrogen), you can get some free 'O' molecules. Which is why you do get some dissolved oxygen in water--but it because it is in a mixture of air (mostly nitrogen).

We are talking O2 here, not oxygen ions or radicals. And it has nothing to do with air being a mixture (except that nitrogen will actually displace oxygen from solution - we use this for de-oxygenating solutions in the lab sometimes).

Conversely, CO2, which we all know as carbonating gas, is non-polar. It is very soluble in water. When you crank the pressure on your corney, you can HEAR the gas rushing into and going into solution. Want 5 volumes of CO2 in your beer? Crank up the pressure. If you tried the same experiment with pure oxygen, you would get nothing.

It has been a long time since college chemistry, so I might have a couple details wrong here. See this link to play around and see how some molecules are polar and some are non-polar. You can also google a ton of things (molecules) and figure out if they're polar or non-polar. Just one last example to "prove" to you this works. Say you have some rust stains on your bathtub. Rust is Iron oxide, FeO2. I can tell you what would remove the stains without ever trying because you know that FeO2 is polar. Will methanol remove rust stains? No. Because iron oxide and alcohols are both polar. (in fact, all alcohols are polar, so you don't need to try any others) What about carbon tetrachloride? Absolutely. If you have some carbon tetrachloride (which is non-polar), it will easily remove rust stains because Iron Oxide is soluble in Carbon tetrachloride.

This is a complicated topic, but rest assured, pure oxygen is not soluble in water (or wort). If you don't believe me, put some wort into a corny and put 30 psi of O2 on it. You won't see any flow (or very, very little). You're better off pouring your wort between two containers and doing a lot of splashing. Happy brewing guys.

So, if oxygen is not soluble in water, when I pump pure oxygen from a cylinder into my fermentors at work (with a water-based medium in them similar to wort), and I see the partial pressure of dissolved oxygen (dO) increasing, what am I measuring? My bacteria - which need oxygen for optimal growth - grow just fine, which they wouldn't do in an anaerobic medium. Please note: I see this with molecular oxygen gas (O2). As an aside, if I use air instead, the dO does not get as high, and my bacteria do not grow so fast. Why would that be?

 

[2-0turbo]

They measure saturation as the percent of the maximum that you get by shaking water in air. This is their 100% point. Which works out to be about 8 ppm. By using pure oxygen gas you can up to 26 ppm in the liquid. That would be equivalent to 325% saturation on their scale. If you want rapid growth of healthy yeast, ~ 21 ppm is what you want to shoot for (according to wyeast; style dependent).

You just can't get 21 ppm oxygen in wort by shaking alone.

Okay, maybe not. I honestly can't measure the level of dissolved O2 in my wort and I don't know how many PPM it is. It is not obvious to me that they are using 8 PPM as "100%". If you reread the original abstract, he didn't say that it was adjusted to be the percentage of each method. It was expressed as saturation only, which would imply some upper limit of saturation.

Because, maybe, in that case, the level of aeration they get is sufficient? It is cheaper, easier and safer to just spray the liquid rather than to need pure O2.

Or perhaps it isn't soluble.

Which is why we use a .2 micron stone to make tiny bubbles. Increased surface area means more efficient transfer.

It's a molecular issue, not a bubble size issue. I argue that a stone will only affect the rate of solubility, not the total solubility or the solubility/non-solubility of different gases. Splitting argon (or Oxygen for that matter) into 0.000001 micron bubbles still won't make it soluble.

And O2 is not very soluble in water. It is not completely insoluble (or fish wouldn't live).

True, but fish need like 6 PPM to live. And I didn't say that Oxygen wasn't soluble in water. I'm saying that pure O2, diatomic oxygen is insoluble in water--which is what comes in one of those red bottles.

We are talking O2 here, not oxygen ions or radicals. And it has nothing to do with air being a mixture (except that nitrogen will actually displace oxygen from solution - we use this for de-oxygenating solutions in the lab sometimes).

Okay, but you're blowing nitrogen through water to de-oxygenate it, not air. Blowing air through water will put some oxygen in the water, but I think it is more to do with the action of getting stirred up and gas exchange at the surface that the bubbles thought the liquid.

So, if oxygen is not soluble in water, when I pump pure oxygen from a cylinder into my fermentors at work (with a water-based medium in them similar to wort), and I see the partial pressure of dissolved oxygen (dO) increasing, what am I measuring? My bacteria - which need oxygen for optimal growth - grow just fine, which they wouldn't do in an anaerobic medium. Please note: I see this with molecular oxygen gas (O2). As an aside, if I use air instead, the dO does not get as high, and my bacteria do not grow so fast. Why would that be?

I don't know. And you know, I don't profess to be an expert at this stuff. I'm a mechanical guy, not a chemical guy. A couple semesters of chemistry and inorganic is all I've got. I'll read up on it some more. I don't dispute that oxygen can be dissolved in water. But diatomic oxygen, is not that soluble. And I don't believe that blowing O2 through your wort does much. Why do we make yeast starters on stir plates? Why don't we make yeast starters with O2 stones and bubblers?

 

[2-0turbo]

Although, I digress. Here is an interesting article (I haven't finished reading it yet) about raising fish on farms and injecting oxygen via various methods.
http://aquanic.org/systems/recycle/ces-240_pure.htm

 

[BioBeing]

Okay, maybe not. I honestly can't measure the level of dissolved O2 in my wort and I don't know how many PPM it is. It is not obvious to me that they are using 8 PPM as "100%". If you reread the original abstract, that is not what he said.

If you read the methods section, that is exactly what they say they do.

Measurement of Dissolved Oxygen
Dissolved oxygen content of the cooled water was measured using a Yellow Springs Instruments (YSI) Model 57 dissolved oxygen meter equipped with a YSI Model 5739 probe, calibrated with water-saturated air, prior to each set of experiments.

According to wyeast, that corresponds to around 8 ppm. Which is sub-optimal.

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.

(although on that page they say yeast need "at least 10 ppm dO". In their slide presentation, 28 ppm is optimal for e.g. a pale ale).

http://www.wyeastlab.com/hb_oxygenation.cfm

Maybe it's just me, but I'd rather trust wyeast than a guy doing a 6th grade science fair project.

 

[Bobby_M]

It wouldn't be the first time big business was wasting tons of money simply because that's the way its always been done.

Suggesting that it must be helpful because they wouldn't do it otherwise is just an appeal to authority.

Everyone appeals to authority with most things in life. Do you go to medical school to know how to treat a disease you acquire? No, you listen to your doctor or ask a few of them because they have the experience and access to the studies. A huge brewery that needs to find the cheapest way to do something will go out of their way to find it.

 

[2-0turbo]

More interesting stuff. http://ddr.nal.usda.gov/bitstream/10113/24298/1/IND91002635.pdf This study indicates that O2 solubility varies with glucose concentrations. So, theoretically, for a "big" beer, O2 is less soluble which is exactly what you need when brewing big beers and trying to coax the yeast along. Whew! I'm whipped, I think I need a beer after all this!

 

[Bobby_M]

And I don't believe that blowing O2 through your wort does much. Why do we make yeast starters on stir plates? Why don't we make yeast starters with O2 stones and bubblers?

I DO inject O2 into my starters before I start stirring.

Did you not see the data I posted that Wyeast collected on the various doubling in yeast colonies per oxygen concentration? If concentration doesn't matter, how do you account for the difference in colony growth?

8ppm is saturation at atmospheric partial pressure so I'm quite sure the linked study was using that figure as 100%.

From http://www.lenntech.com/periodic/water/oxygen/oxygen-and-water.htm

Water solubility of oxygen at 25oC and pressure = 1 bar is at 40 mg/L water. In air with a normal composition the oxygen partial pressure is 0.2 atm. This results in dissolution of 40 . 0.2 = 8 mg O2/L in water that comes in contact with air.

 

[2-0turbo]

If you read the methods section, that is exactly what they say they do.

Perhaps--I agree, it appears that is what they did. It would be nice if the paper stated what the "saturated level" was so you could compare them.

According to wyeast, that corresponds to around 8 ppm. Which is sub-optimal.

My beer has been turning out okay.

Maybe it's just me, but I'd rather trust wyeast than a guy doing a 6th grade science fair project.

I think the paper was okay--you don't have to insults the guys intelligence. It is apparent that he has done more experimenting that you and I. Not the best, but it provides, if nothing else, stimulating discussion. I guess that is the great thing about this hobby is there is a lot of ways to accomplish the same thing.

 

[RushN24]

Maybe it's just me, but I'd rather trust wyeast than a guy doing a 6th grade science fair project.

This experiment is not much different than what a big corp would do, it's just that the big corps have access to 8th grade science equipment, this guy only had access to 6th grade equipment apparently. You have to understand though that this experiment was not designed to be entirely conclusive, I think it really just serves as a good starting point for discussion (which I am glad to see this thread is generating a healthy bit of it.) All I'm saying is don't discredit the guy for trying his best with what he had. We as home brewers run makeshift experiments all the time to draw conclusions without the slightest bit of quantitative data. Our methods are purely qualitative like some of Bobby_M's experiments, for example I think he had a video of one where he tested various pitching rates of yeast. For the home brewer Bobby's experiment provides some great insight, but for Wyeast Laboratories the results might be a little out of their confidence interval. Ultimately, the same applies to this study.

This guy presents an experiment that results in a theory (not a law), the theory is accepted until it is disproved, that is how science works. You take what the last guy said, change some variables and build off of that.

For me, I am a 5 gallon, partial mash brewer, this study, IMO, relates directly to the way I brew and I tend to agree that for a 5 gallon batch shaking a carboy could be the most efficient (most DO in the shortest amount of time) method for aerating wort. Using air stones might result in even higher levels of DO over a longer period of exposure, and that might be the best method for anybody brewing more than 5 gallons at a time. As someone mentioned earlier there's a fat chance any of us are going to pick up 10 gallons or more let alone shake it for 5 minutes.

 

[Beernik]

Losing the battle is stating that wort doesnt need to be aerated.

That's not my argument, dude. That's the other guy.

All I said is the study wasn't meaningless. It's not a PhD thesis, but its not meaningless. Its more accurate if the beer is smaller. Its less accurate if the beer is big.

Sure, higher SG means the boiling point is higher. Sure its tougher to reaerate DO into wort than water because of the higher SG. Sure there is sugar, DMS, FAN, and other things in wort besides water. Sure wort gets a 60 - 180 minute boil.

But non of those will cause a radical departure from their experiment to reality. It might push the graph to the left. It might push the graph up. But I doubt it is likely to significantly change the characteristics of the curve for using air with the goal of obtaining 8ppm DO.

And as far as using pure O2. Using air, 8ppm is the max anyone will get. Absolutely you will get more DO with pure oxygen, you can actually get up to 30ppm. How much DO and how fast depends upon your diffusion method, and how long you leave it in there. However if you get close to 30ppm DO, you risk damaging the yeast cell walls (http://www.byo.com/stories/wizard/a...xygen-canisters-safe-for-homebrewing-aeration)

The bottom line for me, I'm not overly worried about optimum yeast growth. My beer doesn't have a deadline.

 

[Sawdustguy]

I have read alot of these articles and I go with what has worked for me. I aerate the starter and I aerate the wort. I also pitch dry yeast to a starter. I use a simple aquarium pump for aeration because I am too damn lazy to measure the amount of oxygen to aerate with. Brew day is long enough and complicated enough to worry about this stuff.

 

[BioBeing]

If you are happy with aeration and low levels of oxygen, then this study tells you that shaking your fermentor is the fastest way to get there.

If, on the other hand, you are looking to make the best beer possible, then this study actually tells you very little. In fact, it might even confuse you (as it appears to have done some here) and suggest to you that shaking is as good as oxygenation. And that would be wrong.

So, this study is good enough as far as it goes. Wyeast have done everything this guy has done AND MORE. They have blind taste tests to show that, for a pale ale, 28 ppm was preferred over 8 ppm. [For a lager, lower ppms were preferred.] Why not take the Wyeast study as the more authoritative of the two?

And that's all I'm going to say on this subject.

 

[Synovia]

Everyone appeals to authority with most things in life. Do you go to medical school to know how to treat a disease you acquire? No, you listen to your doctor or ask a few of them because they have the experience and access to the studies. A huge brewery that needs to find the cheapest way to do something will go out of their way to find it.

I work in a hospital. When I talk to doctors, I ask for references and do my own research.


Just because a brewery is looking to cut cost, doesn't mean they're doing things in the most effective manner. If everyone was doing things in the most effective manner, progress and innovation wouldn't be possible.

 

[McKBrew]

I have nothing to add, other than this thread should be moved to the debate forum.

Can't believe that people are arguing over this.

Actually, I can.

 

[Bobby_M]

Why would this be moved to the debate forum? It's specifically tied to brewing and practices widely held. We can't debate about brewing on the general brewing forums anymore?

 

[McKBrew]

Why would this be moved to the debate forum? It's specifically tied to brewing and practices widely held. We can't debate about brewing on the general brewing forums anymore?

Sorry Bobby, should have thrown a in there somewhere.

I just find it amusing that people would actually suggest that major breweries would waste money and research to do something that wasn't needed. Or that people get worked up about this to the extent that some do.

 

[Bobby_M]

I'd like to believe the ultimate goal is to make the best beer possible and some of the frustrations and heated opinions are based on the lack of real conclusive one-size-fits-all data. Like, we all know not to put dog **** in the fermenter. If only all other choices were that obvious. I know, next post will be someone arguing that dog **** in the fermenter has never been a problem.

 

[bob1852]

Despite some good dialogue in this thread, here's what I have to say to the rest of it:

Mr. Madison, what you've just said is one of the most insanely idiotic things I have ever heard. At no point in your rambling, incoherent response were you even close to anything that could be considered a rational thought. Everyone in this room is now dumber for having listened to it. I award you no points, and may God have mercy on your soul.

(isn't it time for another glass v. BB debate, or liquid v. dry yeast)

 

[babalu87]

I know, next post will be someone arguing that dog **** in the fermenter has never been a problem.

It would provide for nucleation points for yeast

 

[McKBrew]

It would provide for nucleation points for yeast

And depending on the type of dog food it could be used to bump up the OG a bit. Plus isn't dog doo a natural clarifier?

 

[arturo7]

I wonder if dog doo would be similar to horse blanket?

 

[samc]

Nobody requires that anyone else read a particular thread. Why screw it up with useless inane banter about feces?