Aerate and oxidation Misunderstanding

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philmo418

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OK I am confused.

Is there a difference in these terms? When should you aerate...good thing. What should you do to prevent oxidation...bad thing??

Philmo.
 
There is a difference. As a general rule, you need to add oxygen before fermentation and avoid it after fermentation.

You can add oxygen by shaking, airstone, stirplate for starters, etc. Post-fermentation, you need to maintain your airlock, rack your beer gently, purge vessels with CO2 (if you have the equipment), cap bottles on foam, etc.

And by definition, aeration is the addition of oxygen. Oxidation is the reaction that occurs when oxygen is in the system.
 
You aerate your wort before fermentation. The oxygen in the wort promote yeast reproduction for the fermentation process. This can be done in multiple ways; splashing the wort during transfer, shaking your carboy (with a bung in the end) to the point of splashing the wort, oxygen bottle with an aeration stone.....

Oxidation is after fermentation is complete. This can happen in a lot of different ways but ultimately it happens when the beer is overexposed to air. It doesn't necessarily need to be splashed around, it can simply happen by opening up your brew bucket and allowing the air to come in contact for an excessive amount of time. This is why it's important to transfer your beer carefully but efficiently when it's time to bottle or keg. As long as you don't splash the beer around and get it bottled up quickly then you really don't have much to worry about. But if you start splashing it about or stir excessively/aggressively, then the chance of oxidation increases exponentially.
 
Aeration: adding AIR not pure oxygen to your wort before primary fermentation. (I.E. Shaking carboy, transferring between two kettles, using an air pump not attached to an O2 tank. Not as effective or safe as using pure O2 since air is only about 20% oxygen and may contain airborne bacteria.

Oxygenate: adding pure oxygen from an O2 tank to your wort before primary fermentation.

Oxidation: the negative effect from too much oxygen being introduced to beer after fermentation has occurred. Usually during transferring or bottling. Often described as resulting in a stale taste.
 
Just to add to the previous comments, I do believe I read in how to brew that aerating pre pitched wort above 80f is also risky business as it can chemically bind the oxygen to various parts of the wort. So aerate pre-pitching but when the temp has dropped below 80f is the advice in that book.
 
One thing I've been wondering: hot-side aeration is bad, right? Why? Doesn't boiling drive out the oxygen anyway?
 
If you are boiling as the wort is being transferred I believe it should eliminate potential HSA. If you transfer it before boiling I don't think the boil solves it.

However a lot of people believe HSA isn't really an issue on a homebrewing scale.
 
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