Oxidization

[cowboy7307]

when we put the cooled wart into fermenter we are told to oxygenate the beer by stirring the crap out of it.
But at bottling told be so careful not to oxidize it , why by string before fermentation, not cause oxidization

 

[Donoroto]

Ah, it matters when you add oxygen.

When the yeast is starting out, it needs oxygen in order to get started. Oxygen is good at that stage. Once the yeast has nearly finished, oxygen then becomes a bad thing.

Please note that dry yeast already has what it needs, adding oxygen does not help or hurt.

Only liquid yeast needs oxygen at that stage. This includes a wet (liquid) starter made from dry yeast.

 

[Minbari]

Ah, it matters when you add oxygen.

When the yeast is starting out, it needs oxygen in order to get started. Oxygen is good at that stage. Once the yeast has nearly finished, oxygen then becomes a bad thing.

Please note that dry yeast already has what it needs, adding oxygen does not help or hurt.

Only liquid yeast needs oxygen at that stage. This includes a wet (liquid) starter made from dry yeast.

What he said.

The yeast eats the oxygen in the fermentation process. Oxygen after fermentation will cause oxydation.

 

[cowboy7307]

thanks for info

 

[Craigerrr]

I will say however that if you are using dry packaged yeast, and your wort is under 1.060 there is no need to try and aerate before pitching.
This I learned from the North American rep for Fermentis a few years ago.
I have routinely pitched dry yeast into up to 1.063 wort without aerating, and had excellent results.