Troulble Shoot - oxidation

Brewing Processes
1

I am getting some oxidized notes in my last brew and am trying to figure where in the process that happened.  I know it could be in a lot of places, but am sure I am ignorant of some, so I thought I would ask:

What are some of the causes of oxidation in a all grain brewing process?

What I know: (and therefore pretty sure I didn’t do this in my last brew)
In the sparge, “splashing” into boil kettle
Aerating hot wort

(can not enough time in the bottle give some oxidized “notes” or sitting too long in primary, this one sat for two weeks in primary)
Can “un-Fresh” grains cause this note?

Thanks for all input!

2

How are you racking the finished beer?  Did you use an autosiphon?

3

Yes, I used a auto-syphon to rack.

4

There is often a little tiny bubble that forms right where the tubing meets the racking cane and aeration is occurring to a minor degree as you are racking.  I had the same problem awhile back and got some advice from majorvices and fred bonjour, among others, in a thread buried around here somewhere.  I added a hose clamp to the setup and didn’t have any further problems.

5

I know that bubble, I have seen it as well.

Where do you add the hose clamp, and how does it help prevent it?

6

Clamp the hose to the racking cane.  Just be careful when tightening the clamp because if you go too far the plastic will crack.  Like this (ignore the carboy cap, just look at the top of the cane):

7

I see, and easy enough.  Thank you very much!  Will definitely do.

8

Hot side aeration has been a subject of much debate. I am not convinced either way about the effects of HSA on beer flavor. When I think of oxidation in beer, I attribute the flavor to wet cardboard or sherry-like flavors. Oxidation can commonly occur during any racking step in the process.

Things to consider when racking:

  • use CO2 to blanket keg or carboy
  • careful not to splash beer during transfer
  • allow beer to fill from bottom up during transfer
  • keeping all openings covered
  • proper height for gravity feed
  • use of CO2 to push beer during transfer

These are a few things that will help mitigate oxidation during racking. The first step to minimizing the effects is to have an awareness of O2 and how it can come into contact with the finished beer.

9

Oxidation comes in many aromas/flavors.  What are you getting?

10

Cardboard…

11

You need to be extra careful once the beer is fermented.

If you added water (i.e. the priming solution) was it boiled to de-aerate it?  Don’t spash the fermented beer.  Try and rack as gently as you can, and keep the racking tube under the beer level as soon as you can get it submerged.

I have been using the carboy caps so I can push the beer with CO2 into CO2 purged kegs or secondary carboys.

12

+1 On the CO2 push.  I never siphon anymore.