Aerating a no chill cube? For Lager

[aamcle]

A couple of brews ago I decided to " go simple" straight BIAB rather than recirculating but then I thought (see backsliding already) I've got this nice CFC I should use it.

I brewed a German Pilsner this week, as I needed a pump to recirculate through the CFC I just did a recirculating BIAB.

I auto tuned the PID on water that was great, but with the grain in and consequently very different flow patterns I ended up controlling the temperature manually.
OK did that, then the the 12v power supply for the pump decided 12v was boring and the 4.3v was the thing to get into... So out with a spare 12 v power pack.

I hit the numbers and the wort tastes good so I should be OK maybe even the best thing anybody has ever tasted, well I can always hope!

Next time I want to do a straight BIAB and run it into a no chill cube, no recirculating, no pump and less hassle.

[ I]I would plan to inoculate the wort next day[/I], I could pour it from the cube into a FV whip some air in with a spoon and a power drill or ferment in the cube.

This is particularly for lager at 12°C.

I'd prefer to ferment in the cube but aeration is a issue I don't have oxygen but I do have an aquarium pump and a sterile air filter.

Would simply dropping a weighted airline into the wort and leaving the air bubbling slowly through for a few hours work? That is not using a diffuser stone just a blocked line with a few pin prick holes to make smaller bubbles.

My final thought would be to use a diffuse stone but run the pump on a timer so that after the initial blast it would switch on for say 5 mins every hour for the first 3 or 4 hours then be turned off and removed.

I'd value your thoughts and comments.


Thanks All. Aamcle

 

[rude]

I dont think there is any way around not using o2 if pitching at 12c

You could pitch higher to get the numbers up then take it down to 12c
then finish it off high

 

[SBOB]

I'd prefer to ferment in the cube but aeration is a issue I don't have oxygen but I do have an aquarium pump and a sterile air filter.

Would simply dropping a weighted airline into the wort and leaving the air bubbling slowly through for a few hours work? That is not using a diffuser stone just a blocked line with a few pin prick holes to make smaller bubbles.

My final thought would be to use a diffuse stone but run the pump on a timer so that after the initial blast it would switch on for say 5 mins every hour for the first 3 or 4 hours then be turned off and removed.

I'd value your thoughts and comments.


Thanks All. Aamcle

a majority of aeration pickup when using 'air' via a pump is from the continual exchange of the wort at the surface, and the surface layer being continually changed and oxygen being absorbed there.
So, yes that will work.

Using an aeration stone just makes more fine bubbles which slightly increases the pickup as that bubble makes its way to the surface and causes more convection currents to bring wort to the surface along with them (like in a fish tank), so using a timer and continual bursts isnt really going to be much benefit. Just run it for say 15-20mins and be done with it.

Also, a sanitary filter inline with that air would be a good addition

 

[Blind Dog]

Aquarium pump with sterile in line filter and air stone certainly works for lagers and (IMO) gives better results than simply splashing the wort, using a whisk attached to a drill etc. I've never used straight O2 so can't comment on whether that gives better results based on personal experience, but many on here and elsewhere, insist it does. It's on my list of things to try

 

[altone]

Aquarium pump with sterile in line filter and air stone certainly works for lagers and (IMO) gives better results than simply splashing the wort, using a whisk attached to a drill etc. I've never used straight O2 so can't comment on whether that gives better results based on personal experience, but many on here and elsewhere, insist it does. It's on my list of things to try

Exactly what I do for pilsners.
I use an aquarium pump with a HEPA inline filter and a stainless airstone from the LHBS. for 20 mins.

Obviously science would say pure O2 is way better as you can saturate the wort ,
but I wouldn't even know where to source it and whether the extra cost would make a worthwhile difference.

 

[bevan]

Obviously science would say pure O2 is way better as you can saturate the wort ,
but I wouldn't even know where to source it and whether the extra cost would make a worthwhile difference.

FYI

http://www.brewman.com.au/web/showproduct.asp?prodid=856

 

[SBOB]

FYI

http://www.brewman.com.au/web/showproduct.asp?prodid=856

or for more fun, go read this thread

http://aussiehomebrewer.com/topic/77928-different-wort-aeration-kits/

 

[fdsaasdf]

@OP do you have another cube? If you really want to ferment in a cube with aeration you could just sanitise a hose and siphon it from one cube into another, being sure to splash it around.

When you ferment in the cube how much headspace do you typically leave? Do you use an airlock, plastic wrap or just leave the lid loose on the thread?

Tangentially the last time I did a no-chill lager my fridge was playing up and instead of 12degC it was sitting between 8-9 for a fortnight before I noticed. Surprisingly the Swiss Lager yeast was still active...

 

[dr K]

If you insist on no-chill the why not subsequently chill slowly in the fridge and transfer with much splashing to a secondary cube (a sort of secondary chill if you will).
This will give more dissolved oxygen than CFC chilling and equal splashing. Assuming you chilled the wort to say 2C then the wort in the secondary cube (at say 14C shed temp) will likely settle in at 8C odd, pitch your yeast and ferment at 8C regardless.
K

 

[aamcle]

I'd like to avoid the second transfer that's all, as few as possible seems a good rule.

It appears that O2 is the way to go at least for lager and high OG stuff, Ill start pricing up the gear.

Thanks All. Aamcle

 

[mkj]

Won't colder wort absorb a higher amount of oxygen? At least it works that way with CO2 and bottling.
Or it isn't enough effect to counteract yeast working at slow temperatures?

 

[MHB]

There is a very real upper limit to how much dissolved oxygen (DO) you can get from air, no matter how thoroughly you bubble in air, shake, splash, stir, syphon... it's about 8ppm.
Certainly better than doing nothing but not really enough for bigger beers or when brewing colder (yes O2 is more soluble colder - but the rate yeast activity slows down more than makes up for the better DO)

There isn't a "OSFA" answer the ideal amount of DO will depend on quite a few variables, have attached a couple of good sources for further reading, if you don't want read all of them the IBD link first is well worth spending a few minutes on.

View attachment Oxygen_11.pdf
View attachment Oxygen Solubility 2.pdf

And a couple of good easy reads in BYO
BYO - Keys to wort aeration
BYO - Aerating Wort - Techniques

 

[black_labb]

Mark, do you have any advice for people who would want to continue to bubble O2 theough their wort to replace the absorbed oxygen? It seems like a valid method but it is hard to know how long to do it for (or if it is better to wait x hours for the O2 to be partially absorbed then restart airation to bring it back up to ~8ppm for example).

The only issue I can see is doing it this way there is a bit of guessing as to how quickly the yeast absorbs the dissolved o2 in varying temps, worts and yeast populations, healths and strains.

 

[Lyrebird_Cycles]

Different Mark here.

There's a lag before dormant yeast really start to demand oxygen when they are added to new wort, can be up to 5 hours.

Once yeast kicks off, uptakes rates of between 10 and 20 mg O2 per minute per 1012 cells have been cited so if you have pitched say 200 billion cells (2 x 1011) into 20 litres of wort at 8 ppm O2 the yeast should take up the available oxygen in around an hour.

If you do this, add more oxygen the second time and more the third etc. There's a feedback loop here: the more O2 supplied the better the yeast sterol synthesis will be which will increase their oxygen demand which will....

 

[black_labb]

Thanks Mark. I take it the increase in oxygen demands doesn't happen when a larger concentration of O2 is present initially like you would find with O2 injection to 12ppm or similar.

 

[Thirsty Boy]

You dont want to go too hard with the O2 even for a lager. Too much and you can increase D levels and anyway, O2 is for growing yeast not for fermenting booze. All you need is enough to ferment your booze and give you a decent flavour, any more is at best a waste of extract and at worst, flavour negative.

I like pure O2 for lagers -it works, its standard commercial practice... blah blah. Most people dont have it. An aeration stone works well too, but I'd combine it with Dr K's (as usual) sterling advice.

I normally let my no-chill wort cool completely over a day or two, then put it in the fridge and chill it for a few days, ie to less than 4°C. THEN - I transfer it to fermenter and let it have either the aeration pump or some O2 while its icy cold. The cold wort sucks up way more oxygen! Then you let it warm up to whatever pitching temp you want and it will be at O2 saturation point all the way as it warms, so you cant do better, so its good enough. Dump in yeast- Happy campers.

Probably not necessary for ales - but if you want an actually "good" lager, get used to the extra time and effort they require. There are lots of different "ways" to do lagers, but all the good ones aren't quick and they aren't easy.

 

[Mr B]

Assuming pure O2 aeration - Wouldnt the 02 come out of solution as wort warms up before pitching?

So you may as well O2 at pitching temps or maybe just a tad under?

For an airstone scenario the low temp aeration makes sense.

 

[Lyrebird_Cycles]

No.

"Saturation" is just a description of the concentration at which the [O2] in the solution is in equilibrium with the partial pressure of O2 in air, assuming all the O2 remains available to participate in the equilibrium (eg none reacts with anything).

Yes this equilibrium is temperature dependent so warming an already chilled oxygenated wort will increase the speed at which it loses oxygen to atmosphere but it doesn't suddenly vanish, the new equilibrium point is approached slowly. It also assumes loss to atmosphere outpaces reaction with wort components, the rate of said reactions will increase with increasing temperature*

The rate at which oxygen is taken up into solution is proportional to the difference between the equilibrium partial pressure of the current [O2] and the partial pressure of the gas phase O2. Logically then, having the solution at a low temperature decreases the equilibrium partial pressure and thus increases the difference between that and a given gas phase O2 partial pressure thus increasing the uptake rate. It is therefore standard practice to oxygenate the wort when it's at its lowest temperature and preferably when it's under a bit of pressure. The most convenient place and time to do this is at the exit of the wort chiller during transfer to FV.

Also note that it is not normal practice to warm the wort up for pitching, you are best off pitching at or slightly below fermentation temperature and there is no real point chilling the wort below this.




* You can assume they'll be close to first order Arrhenius kinetics so the rate will roughly double with a 10oC rise in temperature