aeration and yeast

[el beero]

was reading a similar threat re: yeast questions, and have another one that I thought might help others as well.

Ive made 3 batches so far first one was with dry and second and third used smack packs. anyway, in all cases when I transferred from the boiler to the primary (after cooling, of course) I siphoned and quietly at that. My main purpose in that was (well, honestly I thought thats what I am supposed to do) to be able to filter out the hops remnants.

I guess I hadnt heard much about aeration and havent had too much of an issue in getting my yeasties to get workin (although I thought that there might have been issues with my last batch, but i thought I would ask and see if anyone could tell me more about this...

thanks in advance!

[BrewDog]

Yeast need O2 to propagate. With a small number of yeast cells, they will have a hard time fermenting all of the sugars AND all of the fermentation byproducts that they "re-ferment" in your wort. This leaves off flavors. Also, the residual sugars might get fermented by bacteria or wild yeasts, resulting in bottle grenades.

One of my first batches was under-aerated and it tasted like a fruit salad, (apple, banana, and grapefruit). Not good.

A weak ferment is not a good thing. Give them plenty of oxygen and they will make good beer.

[Quin]

It would be OK (even desirable) to splash the cooled wort into the primary. I let mine drop from the kettle valve into the primary. I then whisk rapidly for 5 minutes with a wire wisk. It works for me.

I'm sure there is a specific O2 concentration yeast need for the initial stages of reproduction, but you would need an O2 meter to measure.

[Mad Scientist]

Originally posted by Quin
....I then whisk rapidly for 5 minutes with a wire wisk. It works for me.


Not heard of that one before, I'll bet it works like a charm....only I would boil the thing before it goes into my cooled wort.


BYO did a great article on aeration a while back, I'll post the month (it was in 2006), if someone does not beat me to it.

[Quin]

Yes I soak the wisk along with airlock, primary, etc. in sanitizer during the boil.

I think I saw Jim Koch use a wisk on the homewbrew video on the Sam Adams site. The Longshot commercial and that video peaked my interest and got me started homebrewing.

http://www.samueladams.com/promotions/LongShot/video.html

[iahebert]

Originally posted by el beero
My main purpose in that was (well, honestly I thought thats what I am supposed to do) to be able to filter out the hops remnants.



Do you put your hops in a filter bag? It seems to work well for me.

[Mad Scientist]

Originally posted by iahebert
Do you put your hops in a filter bag? It seems to work well for me.

Hop bag.....what is that?

[dparsons]

Originally posted by Boerne Brew
Hop bag.....what is that?

Its a brown sack that two people put one leg each into and race other pairs of people doing the same. The other people will put up some prize like a pie to get people to do it so that they can laugh at them when they do a face plant.

[larin1477]

No thats an Idiot sack...a hop bag is what you use to catch the Easter Bunny!

[barleyburps]

a whisk sounds like a good idea. . .never thought of that before, I might have to give a try. . .hmmmm . . . I bet a hand held mixer on low speed would also work well.

seeing as that's towards the end of the brewday for me though, I probably couldn't trust myself not to drop the whole thing in the fermenter and electrocute myself.

or as Dparsons would say. . . . .

[Mad Scientist]

what? What would he say????? I'm hanging here.....

[barleyburps]

Shocking, just shocking!

[dparsons]

Maybe thats what happend to Buckwheat.

[barleyburps]

. . . doing the eddie murphy laugh right now. . . how does that play out online?. . . .

[BrewDog]

"'Jo Mama's armpits are so hairy, it looks like she has Buckwheat in a headlock!"

[cbtrtbum]

i utilized the whisk method (i too watched the Jim Koch video) and my bavarian wheat started bubbeling very quickly and is currently going nuts. Good idea. This beer will be turned into a blueberry wheat as i am adding a can of puree to the secondary. Thanks for the whisk suggestion. Peace,Chris

[hicks107]

I just watched some of those chapters and when he adds his malt for priming, he whisks it again. I thought that would cause oxidation, which is bad?

[SirVeza]

I've always used a whisk in the plastic primary as I don't like shaking 50+lbs of hard work with that big lid just hanging there. I've often thought about what if the lid popped open!

I shake when using the carboy, but only because the wisk won't fit down the neck.

While listening to a podcast with David Logston from Wyeast I learned that shaking is the most effective method of disolving oxygen in the wort without using bottled O2. Apparently they did some tests and shaking outperfoms the popular aquarium pump and stone. It's a good workout too!

Whisk away.

Dan

[cbtrtbum]

I brewed a newcastle brown ale clone last night, and used my 6.5 gal carboy for the primary. I shook it pretty well, (with sanitized hands) and pitched the wyeast brittish ale yeast that came in the kit. Seems as though the shake it method works well, because when i woke up this morning, it already had a FULL krausen working, and by tonight had blow up throught the airlock. Just recleaned, sanitized and replaced it. Anyhow, just thought id add my .02 about shaking it. In the bucket i now use the whisk. Peace,Chris

[thekulman]

It depends on the yeast used. Most if not all, liquid yeast needs aeration to multiply. Specifically because most of those smack packs give you far to few yeast cells (make a starter first).

With Nottingham dry yeast - my personal favorite, I still make a starter and aerate, BUT their web site specifically says that Nottingham does not need to be aerated as it's developed in the lab to contain all the energy/nutrients it needs to reproduce without added aeration.

Kul

[SirVeza]

I second the praise for Danstar's Nottingham. It's a total workhorse an always fun to watch. Not to mention makes some pretty fine beer.

Oxygen is needed during the growth phase when the yeast cells are generating daughter cells. During this time, the number of living yeast cells in your wort can quadruple. The primary factor that determines how many daughters can be made is the available oxygen in the wort. So, I would guess that it is always advised to give them as much oxygen as possible.

I think the reason that basic kit instructions do not include a step for aeration is that it is another infection risk. A bad batch is something the companies don't want and they intentionally omit some steps that are complicated or risky for beginners due to sanitation issues. Perhaps Danstar has this same philosophy.

Once I learned about yeast, I have always aerated.


Dan
Homebrewing in the Philippines (http://homebrewinghobby.blogspot.com)