How important is it to aerate?

Brewer's Friend 728
Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
beerman123

beerman123

Active Member
Joined
Apr 5, 2014
Messages
36
Reaction score
3
Location
Chicago burbs
I only have 2 all grain batches under my belt so this is clearly a newbie question...how important is to to aerate wort before pitching yeast? Is shaking the best method? I have not aerated either of my first two batches and they taste just fine. Please explain! Thanks!



Sent from my iPhone using Home Brew
 
Lack of oxygen can result in a longer lag time to fermentation beginning, and potential stalled fermentation. It doesn't guarantee these things, but proper aeration shouldn't be ignored.
 
I don't have any kind of oxygen system myself, but I shake the **** out of my filled carboy for about 5 minutes or until my arm gives out for 3 years now, and haven't had any issues. I'll buy something simpler at some point.
 
I open the valve on my kettle and let the cooled wort drain thru a strainer into my bucket fermenter. I get a huge frothy head which I interpret as a good aeration. I pitch a yeast starter and we're off to the races.

Before I aerated and pitched from a starter, I got a sluggish start.

So... I think it helps.


Sent from my iPhone using Home Brew
 
Proper aeration reduces the stress on the yeast. This means when you are growing your yeast population after pitching, they grow faster and healthier. When they start fermenting the sugars, it means fewer off flavors and better attenuation.

I have a three foot long stir rod that I can connect to a drill.
 
There's a pretty significant relationship between the importance of aeration and the OG, and desired ABV of the beer, which comes back to what everyone has been saying so far.

If you're making a low ABV beer aeration is not going to be as important because the yeast won't be too stressed out, but if you're going above 8% or so you need to help those little guys all you can.

My rule of thumb is that if it's 5-6% an aggressive pour into the fermenter is enough aeration.
 
The three things that improved both the quality and consistency of my beer have been a stir plate for starters, a temp controlled freezer for fermentation, and an O2 tank with air stone. It's certainly possible to make great, even award winning beer without these items, but when it comes to repeat-ability, predictability, and being able to make beer that tastes like it came from a commercial brewer (or better!) I think they are important.
 
Yeast need oxygen to remain healthy for repopulation (lag time). If they don't have access to "enough" oxygen they will be stressed and you can get some unwanted esters, or at least, esters which wouldn't be there if the yeast was healthy.

Higher OG beer need more oxygen. Like said earlier in the thread, if you're making lower OG beers then just shaking the fermentor would be enough. But at the earths atmospheric level you can only dissolve about 8PPM (correct me if I'm wrong on the amount) of oxygen into a liquid. Beers in need of a higher PPM would need to be aereated with oxygen to get a result which can be linked to healthy yeast performance.
 
Flipadelphia said:
I don't have any kind of oxygen system myself, but I shake the **** out of my filled carboy for about 5 minutes or until my arm gives out for 3 years now, and haven't had any issues. I'll buy something simpler at some point.
Click to expand...

I cannot shake 5-6 gallons anymore so:

Aquarium pump, sanitary air filter, stainless air stone (BOIL stone before each use). I run about 20 minutes in cooled wort before pitch.
 
Supposedly aeration is not as important with dry yeast as it is already combined with the sterols it needs for initial reproduction. I exclusively use liquid yeast, so have never tested this. For liquid yeast it is important, and the bigger the beer, the more important it is.
 
Calder said:
Supposedly aeration is not as important with dry yeast as it is already combined with the sterols it needs for initial reproduction. I exclusively use liquid yeast, so have never tested this. For liquid yeast it is important, and the bigger the beer, the more important it is.
Click to expand...

I have tested using dry yeast without aeration and it works fine. Doing a no chill in the fermenter I just opened the lid, dumped in the package of dry yeast and put the lid back on. 3 weeks later I have beer ready to bottle.:ban:
 
Calder said:
Supposedly aeration is not as important with dry yeast as it is already combined with the sterols it needs for initial reproduction. I exclusively use liquid yeast, so have never tested this. For liquid yeast it is important, and the bigger the beer, the more important it is.
Click to expand...


RM-MN said:
I have tested using dry yeast without aeration and it works fine. Doing a no chill in the fermenter I just opened the lid, dumped in the package of dry yeast and put the lid back on. 3 weeks later I have beer ready to bottle.:ban:
Click to expand...

Agree with both, with a qualifier: as long as you don't underpitch. Once you underpitch, the yeast will need to reproduce more and you WILL NEED oxygen for that... So pay attention to pitch rate, and if you don't rehydrate then double the suggested yeast pitch, and you can get away with not aerating (although it still won't hurt if you do).
 
I used to try and shake my fermenter...but I had to stop when I noticed the it was giving heart palps, back problems, and I could scratch my ankles with out bending over. Now I just use an aeration stone.:mug:
 
I exclusively use dry yeast because it's so much cheaper and I think the biggest issue is underpitching, mostly because the viability of the packets are impossible to know, even if you look at the date. I generally try to overshoot my pitch, aerate a ton and filter well.
 
For me there are three realistic methods for aeration; a drill and paint stirrer, an air stone and pump or a O2 tank and an SS air stone.

Shaking is efficient but from the various different test I have seen about the internet it is somewhat inconsistent, because the head space is variable from container to container and the level of vigour in the shaking is different from person to person. It's harder to reproduce imo consistency with shaking plus you risk injury to your back, or dropping the fermenter.

A paint stirrer/drill combo is basically doing the same thing as shaking, but negates all the risks and inconsistencies. So as a budget solution I think this is a great method.

Airpump and airstone can reduce risk of contamination, even if you don't run an inline filter most pumps normally have a pre filter at the drawn-in. Which means you can keep out particulates which carry a high number of bacteria and spores. Cotton wool inline can filter out 2-10um, which actually will include large spores too. IME ss stones and syringe filters don't work well with pumps as they reduce the airflow rate, even though you get an increase in surface area from the SS stone this is less an factor than airlow. A high airflow, say 6L/min from a air pump can aerate 19L in less than 10 mins. A good stone like a Japanese ceramic stone keeps surface area high without reducing flow rate. If you used a SS airstone and a syringe filter unless you are using a oiless compressor or a koi pump (both cost prohibitive) then your flow rate will drop below a litre and min and then you are looking at 60mins to get the same level of aeration.

If you are making high gravity beers above 1.060 then you need O2, as you can only physically get to around 8ppm with air and you need 12-14 for high gravity beers.
 
I have an 02 tank and stainless stone, but for the last year I've been doing no aeration. I make a 2L starter when using liquid yeast. I think the flavor has improved, but I don't brew enough consistently to say for certain.
 
Queequeg said:
If you are making high gravity beers above 1.060 then you need O2
Click to expand...

BS. I've made over 200 beers over 1.060, and never had a problem, many well over 10% abv. My highest I've done was 13%. I always shake, and always get full attenuation. I hate sweet tasting beer, and have no problem drying them out.

Yes, aeration is important, and an O2 set up would seem to help (I've no experience), but to say you NEED O2, I strongly disagree with.
 
Paradigm said:
I exclusively use dry yeast because it's so much cheaper and I think the biggest issue is underpitching, mostly because the viability of the packets are impossible to know, even if you look at the date. I generally try to overshoot my pitch, aerate a ton and filter well.
Click to expand...

As stated already, the need to aerate isn't as great with dry yeast (packaged with sterols) as it is with liquid. The important practice with dry yeast to avoid under pitching issues is proper rehydration in warm tap water before introducing the cells into wort. Sprinkling dry can kill up to half of the cells right off the bat.

Aeration and pitch rate both play an important role in obtaining the number of cells needed to have a good healthy fermentation. Right after pitching, the yeast go through a lag period where they are primarily sprouting new yeast cells. That's an aerobic process which requires sufficient O2. Once the colony hopefully builds up sufficient numbers and uses up the O2, they transition to the anaerobic task of processing the sugars into alcohol and CO2. If they run out of O2 too early, their numbers (depending also on pitch rate) can be lower than optimal potentially resulting in flavor issues or lack of attenuation.
 
Calder said:
BS. I've made over 200 beers over 1.060, and never had a problem, many well over 10% abv. My highest I've done was 13%. I always shake, and always get full attenuation. I hate sweet tasting beer, and have no problem drying them out.

Yes, aeration is important, and an O2 set up would seem to help (I've no experience), but to say you NEED O2, I strongly disagree with.
Click to expand...

Calm down dude. You don't NEED to aerate full stop, the process of aeration is one of optimization to minimize lag phase time and to improve the parent to daughter cell ratio to assist attenuation. As pointed out above other factors such as pitch rate have a bigger impact on attenuation rate that 02, as a growth phase is less significant if your pitch rate is very high as would be the parent cell/daughter cell ratio because attention will still complete before the parents cells reach the end of their life span.

If you want to optimize the aeration process theoretically for high gravity beers you can't do it with air assuming optimized O2 for high gravity beers is above 9ppm, which according to white labs and wyeast it is.
 
The yeast can take up all of the O2 they need for a full fermentation (assuming proper pitch rate > .75 million cells/ml/*P) prior to hitting the fermentation vessel - either in a well aerated starter, or in the case of dry yeast, by simply rehydrating and allowing the yeast to take up the nutrients already packaged with it. If the yeast isn't given that chance ahead of time though, or if pitch rate is significantly lower, the need for the yeast to undergo additional cell divisions creates a need for more dissolved oxygen in the wort. For a high gravity beer, one doesn't need to overpitch for this to happen. A sufficiently large starter grown on a stirplate will allow the yeast to take up the oxygen they need while still maintaining a standard pitch rate between .75 and 1 million cells/ml/*P. Likewise, a sufficiently large pitch of properly hydrated dry yeast needs no additional oxygen.
 
Queequeg said:
Calm down dude. You don't NEED to aerate full stop, the process of aeration is one of optimization to minimize lag phase time and to improve the parent to daughter cell ratio to assist attenuation. As pointed out above other factors such as pitch rate have a bigger impact on attenuation rate that 02, as a growth phase is less significant if your pitch rate is very high as would be the parent cell/daughter cell ratio because attention will still complete before the parents cells reach the end of their life span.

If you want to optimize the aeration process theoretically for high gravity beers you can't do it with air assuming optimized O2 for high gravity beers is above 9ppm, which according to white labs and wyeast it is.
Click to expand...

O2 is consumed by yeast within about 30 minutes, so it is completely feasible to aerate a second time post pitch. Or just add the yeast before stone and pump aerating and run that out to 30 minutes or so - I had forgotten I used to do exactly that this with fairly explosive results :)
 
Interesting opinions on this. I also believe it's more about pitch rate than aeration.


Sent from my iPhone using Home Brew
 
pablosbrewing said:
http://morebeer.com/articles/how_yeast_use_oxygen

Edit: Re-aeration I got from aeration article in the current zymurgy (may/jun 2014)
Click to expand...

Whoeee, there's a lot of info to digest in that article. I'm glad you posted it. Now I realize the need for oxygen to help the yeast cells produce the sterols required for cell wall health. Now, how does that fit in with the discussion of using olive oil for the source of sterols and will that negate the need for aerating the beer?
 
RM-MN said:
Whoeee, there's a lot of info to digest in that article. I'm glad you posted it. Now I realize the need for oxygen to help the yeast cells produce the sterols required for cell wall health. Now, how does that fit in with the discussion of using olive oil for the source of sterols and will that negate the need for aerating the beer?
Click to expand...

And just to add in to the already vast amount of info coming with this hobby. Adding olive oil apparantly alters the oil utilization (or something like that), so you'll get a different aroma from your hops. I read that in another issue of zymurgy. but I unfortunately cant recall the name of the article.
 
When my beers are well aerated and I use nutrient, they just taste better. They finish quickly and they taste great right away. It's important. Not vital, but definitely optimal.

I don't use oxygen, but I do the pour method. Get two buckets, sanitized, and pour your wort back and forth from as much of a height as you can. You will get a big, frothy, foamy mess in no time. This is better than shaking or rocking or whatever, you get a much, much more effective aeration.

And before someone says this is a contamination risk due to air exposure, it absolutely is not. Airborne contamination is like a f'ing unicorn, contamination comes from surfaces. Your happy, energized yeast will more than make up the difference and outcompete any bugs in the wort.
 
fearwig said:
Airborne contamination is like a f'ing unicorn, contamination comes from surfaces.
Click to expand...

Trust me its not, its lower risk than surfaces, and surfaces are lower than personal, but you can still get very high contamination in air samples even from controlled environments. Though I have never taken a SAS or settle plate sample in my kitchen I would suspect it would be quite high.

The main thing is the presence of a monoculture out competes the contamination of mix flora.
 
I have a metal 5 gallon paint stirrer that I sanitize, attach to drill, and whip the crap out of it before pitching.
 
Queequeg said:
Trust me its not, its lower risk than surfaces, and surfaces are lower than personal, but you can still get very high contamination in air samples even from controlled environments. Though I have never taken a SAS or settle plate sample in my kitchen I would suspect it would be quite high.

The main thing is the presence of a monoculture out competes the contamination of mix flora.
Click to expand...

Right, I mean actual contamination of pitched wort, there is definitely a lot of bacterial presence in the air, especially in a kitchen. The deal is to compete with yeast you'd really need exposure to a whole colony of the bug for it to have a fighting chance, even specks of dust are pushing it unless it's raw grain dust or some truly special kitchen filth. :)

And kitchens are probably the dirtiest room in the house for beer contaminants, which always surprises people, somehow.

Point is, you shouldn't worry about air exposure during wort aeration unless you're willing to go to HEPA or O2, because air exposure is the point, so people should pour away.
 
Its hard to know the risk really, it depends what you have floating around in your kitchen. If you use the pouring method and get no issues then stick with that.
 
So I just used oxygen on my first batch, using a starter I prepped two days ago. Seriously, the airlock is bubbling steadily after 15 minutes. I'm not sure what overall effect it will have on the finished product, but I'm impressed by how quickly this started. I've shaken the hell out of previous batches, and even with an active starter it has been a good 8 hours or so before signs of fermentation.
 
That bubbling was probably excess O2 off-gassing. If it really started in 15 minutes, I would suspect a large overpitch. A lag phase is a normal part of a healthy fermentation - that is when the yeast is scavenging your wort for nutrients and beginning to change the environment to fend off competing organisms.
 
boydster said:
That bubbling was probably excess O2 off-gassing. If it really started in 15 minutes, I would suspect a large overpitch. A lag phase is a normal part of a healthy fermentation - that is when the yeast is scavenging your wort for nutrients and beginning to change the environment to fend off competing organisms.
Click to expand...

Yep ^^^^^.
 

Similar threads

cayugalakebrewer
Aerating Partial Boil?
Replies
1
Views
211
hotbeer
hotbeer
S
To aerate a 2nd time for OG 1.088
Replies
14
Views
628
mac_1103
mac_1103
D
Aerating Wort via Fly Sparge?
Replies
6
Views
541
DonT
DonT
C
No activity
Replies
14
Views
728
cleaner72
C
level-one
Should I aerate wort for a hazy ipa?
Replies
7
Views
1K
level-one
level-one
InkBird 300

Latest posts

Back
Top