Minimizing Oxidation with Keg Distribution

[amills]

Hello All,

We are a smaller nanobrewery looking for some advice from the professionals.
Any suggestions would be greatly appreciated.

Here is what we know so far:

- All Beer styles brewed and kegged the same as far as oxygen exposure is concerned.
- Darker the beer the faster the oxidation pops up.
- Wheat/Light beer no sign of oxidation after transporting.
- Slight RED beers, after 1-2 weeks slight signs of staleness detected.

- Darker RED beers, staleness detected after few days.
- Brown beers, "alcohol bite" after couple days.
- Dark beers, stout, imperial stout pronounced alcohol bite, quite hard on the imperial stout.
- Highly hopped RED IPA no affects for weeks after distribution.

- Wheat and slightly RED beer have similar levels of alcohol.
- Red beers more flavor changes where darker beers is more of an alcohol bite.


We have been told to invest in better equipment but is not really an option for us.
We have also been told to focus on hot/cold side aeration and kegging processes.

Without being able to invest in better equipment we did however make a number of changes in our kegging processes.
All vessels pre purged multiple times/ways of 02 prior to transferring and packaging.

By these methods and others we have reduced the oxidation affects on the beers substantially.
Now all the beers are good after distribution with exception to the light wheat beer remains same very good quality.

This led to searching what could cause accelerated oxidation the darker the beer.
Maybe focusing on this might help further improve the quality of the beer.


Ran across this...

-Aldehydes are formed by oxidation of higher alcohols in beer with melanoidins.
-Darker malts have more melanoidins due to the kilning process.
-Also read the acceleration in part takes place due to lower PH of the finished beer.


--- So am wondering, might there be a way to help neutralize the affects of melanoidins?
      --- Haven't tried it but could increasing the PH of the finished product help protect against aldehydes?


Thank you for your time & appreciate.

[KellerBrauer]

Greetings amills,  your situation is quite perplexing indeed.  However, my initial thoughts were not oxidation, but rather a possible issue with your base malt and it?s affect from your water.  Could it be that you have had a run of either bad, or sub standard, base malt that you only use, or use more of, in your darker beers?

Furthering this thought pattern, could your water have changed and now you?re realizing an issue?  I?m sure you have a put great deal of thought into this problem, but sometimes issues such as this are better solved by stepping outside the box and looking at all the commonalities between styles as they relate to your complete brewing process and ingredients.

Just some thoughts.

Good luck, I hope you get on track soon!

[Ck27]

Greetings amills,  your situation is quite perplexing indeed.  However, my initial thoughts were not oxidation, but rather a possible issue with your base malt and it?s affect from your water.  Could it be that you have had a run of either bad, or sub standard, base malt that you only use, or use more of, in your darker beers?

Furthering this thought pattern, could your water have changed and now you?re realizing an issue?  I?m sure you have a put great deal of thought into this problem, but sometimes issues such as this are better solved by stepping outside the box and looking at all the commonalities between styles as they relate to your complete brewing process and ingredients.

Just some thoughts.

Good luck, I hope you get on track soon!

I had a similar problem myself and changed malts, tried different brewing methods changed my water and figured out it was my water causing the problems.

[brewfun]

Hi Amills;

There are hundreds of ways to oxidize beer in a pro environment. Although I'm quite sure you've done your research and have the basics covered, I have a few questions for you because I think you have more than one pathway. To have beer oxidize in days means there is a pretty massive ingress pathway, somewhere.

Questions:
How do you measure O2 into the fermenter?
Open or closed fermenters?
Do you use water to chase or purge your hoses?
Do you water back for volume?
Do you filter? Type?
What is your sanitizer?
Is vourloff a gentle flow or turbulent in some way? Is there foam where it reenters the mash?
When is the last time you changed or checked seals in your pumps?
Ask your CO2 supplier what grade of CO2 you're getting. It should be food grade (99.9% pure), if they offer it.

Over use of PAA can leave lots of O2 available to react with beer. Sanitizers and acid cleaners should not be allowed to foam if they're pumped.

Internal pump seals (C-114) can work loose if cavitation has occurred, or even under normal use. Make sure that you're setting pumps to push, not pull beer and wort.

Based on some of your symptoms, I'm thinking that a pump or your filter is the source.

[killian]

From your description I would look in the water and malt direction also. If it were oxidation I would expect that you?d be picking up and describing more green apple or paper cardboard flavors. You didn?t give a recipe but I might try changing up the recipe and coloring your beer with midnight wheat or carafa and see what difference that makes. You could also try top mashing the dark/roasted grains, grind the grain fine, add it to the top of the mash and recirc over it.