Aerating water

MyQul said:

Nomally your supposed to aerate your wort which I do. But I think I read at somepoint this week or just had a flash of inspiration - not sure which, about aerating water.

As a maxi-BIABer I need to dilute my concentrated wort down to target OG. So I filled a 5L plasic jerry can with water and shook the bejesus out of it. I opened it a couple times then squeezing the sides to replace the oxygen that had be disolved in the water (not sure wether doing this has any effect at all but I did it any way) I then diluted my concentrated wort down as usual. Followed by aerating with a mechanical whisk, rehydrating my yeast and pitching - all as normal.

Two observations. 1) When I aerated the wort with the mechanical whisk. There was far more foam on the top of the wort than usual and it hung around which it normally doesn't. 2) My fermentation started faster - in about 9hrs when usually it's about 18-24. It's defiantley not down to being warmer because I've also been experimenting with an ice&water, water bath and have managed to keep the temps between 19C-21C

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Twostage said:

I would have thought that increasing the concentration of O2 in the wort would have increased the lag as the yeast would have had more to go at.

I've done tests of cider and wine where I've used a fish tank aerator on half of the batch and that half always has a longer lag than shaking it. My double aerated lager also had a longer lag than the single aeration.

That said shaking the dilution water must have increased the dissolved O2.

A split batch test is needed :ugeek:. Happy to volunteer, is there a thread with your maxi BIAB method somewhere ?

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Hopping_Mad said:

Once you have your wort in the fermenter at the right temperature, but without yeast pitched, I thought was the most dangerous time for infections - i.e. before the yeast starting fermenting and releasing a protective layer of CO2? Surely you don't want to introduce the air then?

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MyQul said:

Re: O2 and lag time, I haven't a clue tbh, time to do some more research

I haven't written up my maxi BIAB method. Will have to do a post

Thing is I've been experimenting with a number of things this last brew - aerating the water, seperating the wort from the trub and water baths

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Twostage said:

Re:separating the trub. I read recently an article that said the yeast wants the trub, uses it to make its cell walls during the lag phase I think. With last night's 10 litre brew I poured it all into two 5 litre water bottle/FVs, the second one ended up being 50% trub which I thought would be a diasaster. Tonight it has been digested down to about 1 inch at the bottom. It will be interesting how the two halves compare.

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DoctorMick said:

Why haven't I thought about using a whisk for aerating the wort before? It's such an obvious solution!

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MyQul said:

You need to aerate your wort for the yeast to use as during the boil you've boiled any oxygen out of it.

My wort is sitting in the fermenter covered with cling film. Until I take the cling film off it's almost sterile as I boil my wort chuck it in the FV when its near boiling then cover with air tight cling film covering

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MyQul said:

I'm aware that yeast the fatty acids in trub. I'm pretty sure I'm not seperating 100% of it out as I think that would be almost impossible unless you use proffessional grade equipment. Also as I no chill, there's still the cold break material in the wort which is evedent if I put my beer inthe fridge because of chill haze. So over all I think there's still enough in there for the yeast to use

There's a bruslosophy experiment on lots of trub vs no trub

http://brulosophy.com/2014/06/02/the-great-trub-exbeeriment-results-are-in/

The reason I'm seperating the trub out is to make yeast harvesting easier.

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