Wort Aeration

[chappo1970]

That what's I thought in my limited knowledge and reading but I did ask Frank again separately later on and he was pretty positive about the 3ml to 21lt of wort. Anyway I will keep you posted to the results.

 

[JonnyAnchovy]

I think this was one of the orignal articles outlining the process. in the experiemnt they do a 360 HL batch with 15ML of Olive oil, if i'm not mistaken that'd mean around 0.01ml for a regular 22L batch.

Someone please correct my math!

 

[chappo1970]

Nothing wrong with your maths JA. Read that article again last night as well. As I said he was very insistant on the 3ml. Anyway I'm sure time will tell.

 

[JonnyAnchovy]

Let me know how it goes- I'm thinking of going down the ooil path soon.

 

[katzke]

I think this was one of the orignal articles outlining the process. in the experiemnt they do a 360 HL batch with 15ML of Olive oil, if i'm not mistaken that'd mean around 0.01ml for a regular 22L batch.

Someone please correct my math!

I listened to the program that had the info on Olive Oil and I remember them saying something about a toothpick and the small drop that would form on the tip being almost too much. I think the program was linked from one of the posts in this thread but can not say for sure with out looking back.

I also recall something about the oil being added to the starter to give the yeast cells extra nutrient that is used when they divide in the wort.

 

[Wolfy]

I listened to the program that had the info on Olive Oil and I remember them saying something about a toothpick and the small drop that would form on the tip being almost too much.

That's exactly what I remember also, a 3ml measure must mean its a big toothpick.
At the same time it's hard to imagine how 0.01ml does much either.

 

[muckanic]

In practice, you probably couldn't accurately do less than about 0.5 mL using something like a medicine dropper. Apart from the impact on head retention, I am wondering if 3 mL of olive oil could have flavour effects, in which case a cereal oil like from corn, wheatgerm or rice could have advantages even if the fatty acid profile is not quite ideal. I also occasionally use raisins as a vinosity booster in some old ale styles, and I used to fret about getting rid of all the vegetable oil coating. Maybe not any more?

There is of course always the tried and trusted route of using break as the unsaturated fatty acid source instead of throwing it down the drain! Hot break can result in some sulphides that may or may not vent off eventually, but cold break is usually OK. I know some brewers have concerns about the potential for lipid staling, but that presumably applies whether the extra lipids come from the ingredients, supplementary vegetable oil or even yeast. Plus, this effect would be presumably offset by the lack of deliberate O2 introduction (and consequent staling), bearing in mind the whole time that yeast is a reductant anyway.

 

[chappo1970]

After this all popped up last night I couldn't help but be a little worried. The old "Have I ruined my brew" shuddered thru my mind. So I checked the eye dropper I used, it was only 0.5ml, I thought it was 1.5mil, so it would appear that I only added 1ml not 3ml as previously stated. However it's still 100 times the amount if you go off 0.01ml. I guess I will just have to wait and see huh?

 

[apd]

After this all popped up last night I couldn't help but be a little worried. The old "Have I ruined my brew" shuddered thru my mind. So I checked the eye dropper I used, it was only 0.5ml, I thought it was 1.5mil, so it would appear that I only added 1ml not 3ml as previously stated. However it's still 100 times the amount if you go off 0.01ml. I guess I will just have to wait and see huh?

I'm sure you'll be right, Chappo. Even 3ml in 20L or so is a tiny amount. And if it's still floating around when you rack to secondary or bulk prime, you can easily leave it in with the trub.

I tried the olive oil thing by dipping the end of my thermometer in oil and sticking that in a starter. The starter was fine. The wort was never aerated.

It really makes sense to be aerating (or oiling) your yeast during the starter phase, not your wort. It's the yeast that needs the oxygen or sterols (or whatever is in the olive oil), not the wort. Once you've built up your starter, the yeast don't need any more of the nutrients required for replication, so why put those nutrients in the wort and potentially make it stale?

Andrew

 

[muckanic]

With oiling a starter, the issue arises of how the yeast know when enough is enough (ie, when to stop replicating and start fermenting). They very well could optimise the ferment of the starter, but they have no way of knowing what the intended ferment size is. With O2, they stop replicating when the supply is turned off. Maybe this is an argument for adding the oil in a similar progressive fashion, or for oiling the actual ferment as well?

 

[chappo1970]

After my little escapades this week eg trying the olive oil. I'm still quietly pooping my self BTW. I have been trying to read and absorb as much information on yeasts, life cycles, farming, cultivating etc. It's a very exhaustive subject just on it's own.
Anyway because of my welding etc I have a "E" sized bottle of medical grade O2 that I could use to aerate the wort via an airstone. What isn't overly clear on the subject of pure O2 aeration, well to me anyway, is how much? for how long? at what flow rate? Nothing definitive more stabs in the dark FWIW.

newguy breifly mentions something below and there are few more references of "give it a blast for 30 secs" kinda of stuff but what is the proper procedure for O2 injection to obtain the 10ppm required? Is there one?

Anyway I would appreciate any advice or help on the subject from the AHB guru's.

I give my wort a shot of pure O2; 30 seconds for the first pitch from a starter and 0-15 seconds if repitching onto a yeast cake (depends on the beer) - very high gravity brews usually get more. I've always built up pretty large starters but only relatively recently have I started using O2. I started using O2 because I was getting stuck fermentations even though my lag times after pitching were reasonable (6 - 12 hours). For me, O2 was introduced as a fix to a problem I was consistently having, not because the homebrewing literature said I needed it or because I was worried I was underpitching. Even though I have no way to confirm/count the number of active cells I pitch, I'm pretty sure it's in the proper ballpark.

 

[alowen474]

I had a bit of a look at oxygenating wort and Greame from Murrays sent me the following advice
"To put things basically, you need, depending on who you want to listen to, 14ppm of oxygen, so in 56 litres you need around 1 litre of O2 (56 x .014), but at 20c you will only dissolve around 50% into the wort, so you therefore need 2 litres of O2. If you use O2 you will need a flowmeter (litres/min) on the oxygen so you inject it at 1litre/min for two mins, or 2litres/min for 1 min, etc. This is a bit simplistic but works ok...."

Some good info.

 

[Ross]

Anyway because of my welding etc I have a "E" sized bottle of medical grade O2 that I could use to aerate the wort via an airstone. What isn't overly clear on the subject of pure O2 aeration, well to me anyway, is how much? for how long? at what flow rate?

Anyway I would appreciate any advice or help on the subject from the AHB guru's.

Chappo,

Standard brew - 30 seconds with a 0.5 micron airstone. The flow rate should be set so the oxygen bubbles are only just breaking the surface.
These timings are through actual experiments using a dissolved oxygen meter, as I too couldn't find a definitive answer.
Happy to demo, next time you drop by the shop.

Cheers Ross

 

[newguy]

I had a bit of a look at oxygenating wort and Greame from Murrays sent me the following advice
"To put things basically, you need, depending on who you want to listen to, 14ppm of oxygen, so in 56 litres you need around 1 litre of O2 (56 x .014), but at 20c you will only dissolve around 50% into the wort, so you therefore need 2 litres of O2. If you use O2 you will need a flowmeter (litres/min) on the oxygen so you inject it at 1litre/min for two mins, or 2litres/min for 1 min, etc. This is a bit simplistic but works ok...."

I agree that if you were bubbling pure oxygen through water, then the 50% absorption rule would apply as the bubbles would quickly burst. However, when you bubble oxygen through wort, the oxygen doesn't escape the wort at all - it forms a thick, krausen-like foamy layer on top of the wort which doesn't subside. The bubbles simply don't "pop." This nice foamy layer is where the yeast can do their thing and reproduce because there is such a large surface area of wort in contact with pure oxygen. I'm pretty sure that the absorption is close to 100% in wort......if a proper SS airstone is used.

Chappo: Read this, particulary the graph on page 4. Unfortunately they didn't investigate pure oxygen with an airstone. However, this presentation does tie DO levels to the amount of time pure oxygen is used. You'll have to scroll through quite a few pages to get to the good stuff - maybe 20 or 30.

 

[newguy]

OT?

Those who give pure Oxygen to wort. Is there any hop aroma losses? Usually thinking, if hop aroma are gone reason or other, that was oxy what are destroy it.

No loss that I can discern. Pumping pure O2 through an airstone into wort results in no bubbles that break, therefore there is no vapour loss from the wort. There may be a breakdown mechanism whereby the oxygen interacts with the hop compounds but, again, I haven't noticed a difference in my beers.

 

[chappo1970]

Thanks guys now I am starting to get somewhere. But you can see from the below quotes where my confusion comes from. All these quotes from the thread, in fact this one BTW. It just seems to me that the subject of O2 aeration and the amounts are more or less subjective and open to opinion and interpretation. 10ppm, 5ppm Ale, 10-12ppm lager and 14ppm carte blanche. I'm not doubting anyone knowledge on the subject but which is the right answer?

...get the dissolved O2 up to 10ppm...

....
* Ale yeasts need about 5 parts oxygen per million in wort, while lagers can need 10 to 12 parts oxygen per million.

...14ppm of oxygen...

Chappo,

Standard brew - 30 seconds with a 0.5 micron airstone. The flow rate should be set so the oxygen bubbles are only just breaking the surface.
These timings are through actual experiments using a dissolved oxygen meter, as I too couldn't find a definitive answer.
Happy to demo, next time you drop by the shop.

Cheers Ross

I will be on Saturday Ross for some more grains etc so I look forward to catching up and having a look. Thanks for the offer.

I agree that if you were bubbling pure oxygen through water, then the 50% absorption rule would apply as the bubbles would quickly burst. However, when you bubble oxygen through wort, the oxygen doesn't escape the wort at all - it forms a thick, krausen-like foamy layer on top of the wort which doesn't subside. The bubbles simply don't "pop." This nice foamy layer is where the yeast can do their thing and reproduce because there is such a large surface area of wort in contact with pure oxygen. I'm pretty sure that the absorption is close to 100% in wort......if a proper SS airstone is used.

Chappo: Read this, particulary the graph on page 4. Unfortunately they didn't investigate pure oxygen with an airstone. However, this presentation does tie DO levels to the amount of time pure oxygen is used. You'll have to scroll through quite a few pages to get to the good stuff - maybe 20 or 30.

:icon_cheers: Thanks newguy for the links I will digest that info over lunch.

 

[onescooter]

Just wondering what the difference is between medical grade 02, and run of the mill 02 from an oxy acetylene kit.

 

[mika]

Not a lot if you run it thru a HEPA filter.

 

[chappo1970]

Chappo: Read this, particulary the graph on page 4. Unfortunately they didn't investigate pure oxygen with an airstone. However, this presentation does tie DO levels to the amount of time pure oxygen is used. You'll have to scroll through quite a few pages to get to the good stuff - maybe 20 or 30.

Thanks newguy! Great info BTW and exactly what I was looking for, some science to back up the methods vs results vs BS vs Intermernet Genius vs urban legend... you get the idea. I owe you beer if your ever this way! :icon_cheers:

EDIT: Looks like I will buy an airstone off ya Ross BTW. Keep one aside for me.

 

[muckanic]

At the risk of stating the obvious, all this stuff on flow-rates and whathaveyou is critically dependant on whether one is oxygenating a starter or the whole wort. It was concluded way back at the start of this thread that oxygenating the starter alone is preferable in order to avoid beer staling. It would sure also cut down on O2 consumption which, unlike air, isn't free. I would add another, less-recognised point: that replicating yeast puts out a different spectrum of byproducts than fermenting yeast. I think this is an implicit reason why folks sometimes recommend throwing the starter supernatant away, although those byproducts could actually be desirable in certain beer styles. A final bleeding obvious observation: oiling the wort is not a direct substitute for big yeast starters, due to the greater yeast growth in the former.