Beer got darker once kegged

Brewing Processes
1

Kegged up a saison about two weeks ago.  Tapped it today and it has gotten darker in the keg.  And it just doesn’t taste right.  The color is weird, like it has raspberries or something in it.

The keg was clean and sanitized and still had starsan foam in it, so I know there wasn’t any other beer in there.

I saved the yeast slurry and took a side by side photo of the beer from the keg and the beer from on top of the slurry.  The beer from the slurry still tastes great, so whatever happened went wrong in the keg.

Any one have any ideas?  What sort of infection will make a beer darker?


photo_zps56477ae6.jpg

I’m going to brew this saison again, but with the weirdness once kegged I’m not sure I should use the yeast slurry.

2

Oxidation can cause darkening, but that seems pretty extreme.  Did your yeast slurry have any water added that would ligtetn the color?

3

Nope. No water added.

I thought oxidation, too. But I vented the headspace when I filled the keg. At least I assume I did as that is SOP. I don’t take any notes about that.

You can’t see it in the photo but it’s a weird reddish pink. Even the foam looks pinkish.

4

Perhaps it is contaminated somehow? And, is 2 weeks enough time for an infection to show itself that aggressively?

If you were “sampling” and/or distracted during cleaning and racking something might have been missed. ;D Perhaps the diptube has gunk in it.

5

I have seen oxidation dramatically darken a beer. Did you purge the keg with Co2?

6

I did not purge after dumping the star San and before filling. It’s possible I failed to purge the headspace before hooking up the CO2. If so, shaking to carb would have oxidized the beer pretty quickly. Its pretty much all I can think of.

7

I brewed a hefe a long time ago, and somebody bumped into the airlock accidentally after fermentation stopped, breaking the seal on the stopper.  The thing oxidized from a pale hefe out of the kettle to what looked just like a dunkelweizen.  Only didn’t smell quite as good - think wrapping a dog in cardboard and soaking it thoroughly, and you’ll get the idea. So it can dramatically darken a beer.  BTW I worked out a little better security for my fermenters after that fiasco!

8

So I guess this could be an argument for bottling.

Since it looks like there’s nothing wrong with the yeast I’m going to rebrew it and pitch the slurry.

9

I’ve had way too many bottled homebrews that suffered from oxidation in one state or another. Just purge the keg before filling. Pressurize it to about 5 - 10 psi, release pressure, repeat. As simple as that and you will improve the quality of your beer!

You can even rig up a siphon that fills through the QDC on you “out” tube and vent the pressure out the “IN” QDC. You don’t have to crack open the keg. Closed system. Works like a charm!

10

This is too much darkening but consider this.
Cloudy beer is lighter in color then clarified beer.

11

I usually purge the headspace after filling though obviously I failed this time. Not looking to transfer under pressure but I’ll be purging the kegs before filling from here on out.

The worst oxidized bottles beer I ever had was a Saison. I used plastic corks. Beer turned brownish and nasty. Much like what I have now but nastier.

12

I actually think the darker one is cloudier. Doesn’t look like it in the photo though.

It has a bad chill haze, too. Cloudy, pinkish beer.  Yum.