Aeration question

[Burtlake1985]

Hello All:

I just brewed my second batch and my first BIG Beer (Double crooked Tree Clone) OG was 1.115.

Question: I was trying to figure out a way to aerate as much as possible before I pitched my starter, so as I was cooling my wort, i took my wort chiller and rapidly moved in and out of wort. I did this several times for about the last 5 mins that my wort had to cool. Then I poured into my bucket, then took a reading, then pitched. I really feel I gave this wort a beating/splashing.

Anyone try this technique?

 

[boydster]

How big of a starter? How did you aerate the starter?

A starter large enough to hit a pitch rate of .75 to 1 million cells/ml made on a stirplate will be better equipped with O2 reserves for a healthy fermentation than one made without any agitation at all.

 

[Burtlake1985]

My starter was 2L. and a couple hours before pitching I let it warm up and shook my starter in the flask.

 

[NTXBrauer]

I don't know how much O2 you introduced with your method. I actually picked up a mix-stir rod and mix my wort in the carboy really well, after pouring it in through a strainer.

For all my starters, I let them mature for at minimum 48 hours. It is doubtful that 2 hours did more than rouse and wake up the yeast a bit. No harm though, just keep in mind that you may have to re-pitch as fermentation may stall with this big a beer.

Cheers!

 

[Burtlake1985]

Well I made my starter 3 days prior, let it sit at room temp, then 24 hours before before brew time I put it in the fridge, then decanted most of the "beer" and then shook up the settled yeast a couple hours before to let it warm up.

 

[NTXBrauer]

Well I made my starter 3 days prior, let it sit at room temp, then 24 hours before before brew time I put it in the fridge, then decanted most of the "beer" and then shook up the settled yeast a couple hours before to let it warm up.

That is good news...Then your starter should be ready to roll. I expect that your beer will turn out fine.

 

[dannysk]

Especially for a starter, O2 is super critical since the whole objective is to grow yeast. Remember, when it comes to growing yeast, O2 is the limiting nutrient, i.e., the amount of yeast you grow is totally dependent on how much O2 they see for sterol production.

That being said, the best thing to do (IMO) is to inject sterile air into the wort with a pump through some of a sintered stone. At ~ 17 OG wort, at ~ 60 dF, O2 saturation is about 9ppm. There is no way you can get close to this by doing what you described. If you want more O2 you can inject pure oxygen which will give you approximately 50% more due to the higher saturation of O2 in wort when injecting O2 (vs. air); the difference is due to Henry's Law. However, I have found that this is harder to control and be consistent and will impact beer flavor. Invest in a small aquarium type pump and air filter... you will not be disappointed.

Cheers.

 

[dannysk]

At ~ 17 OG wort...

I will never get use to the British method of specific gravity; I am used to and will always use the German (I believe) convention of using original gravity, AE, RE, etc.

The 17 OG I reference above is about 1.06975.

 

[Weizer]

I agree with dannysk. I got my O2 kit from more beer for $55(not much more expensive than a manual pump). It includes everything but the o2 tank, which are $10 at home depot or lowes. I go by what Chris White/Jamil's book on yeast says and do pure o2 for approx 60 seconds to reach approx 9ppm. I would highly suggest getting their book off of Amazon, it will change the way you brew!

EDIT:
You will not even break 5ppm by shaking. That's if you shook it vigorously for 5 minutes straight.

 

[boydster]

Yeast will pick up much of the O2 needed for a complete fermentation cycle while in the starter as long as the starter is well aerated and your pitch rate is sufficiently large. If you can't directly inject O2 into your wort, try using a stirplate starter and pitching closer to 1 million cells per ml instead of .75 million/ml along with your normal aeration routine.