why the perfect split in color?

[70Cuda383]

so, my first REAL batch of home brew is well on it's way, and I'm feeling much better about this batch, using a real carboy and I can see all kinds of fermentation activity going on! the Mr Beer kit batch is still sitting there, not doing much, just waiting for me to bottle it and see what happens...

but, it's got a perfect split in the color of the foam at the top. any idea's why this is, and what's causing it? the carboy is in the basement in the bathroom, so it's totally dark when it's alone, the lights are incandescent, so when I do walk in, it's not like I'm killing it with UV light from florescents. the lighter color is on the side that faces the light when I turn it on...am I killing something with the light?

or, what else would be causing this weird "perfect split" in the color of the foam?

 

[Skyforger]

Is there more heat on one side maybe?

 

[DannPM]

Uneven level it was sitting on for the duration of fermentation?

Did you tilt it at all?

Did you siphon off half the yeast cake by accident just leaving sludge on one side? (seems most likely to me.) Remember which side you siphoned from?

 

[Hang Glider]

Turn it. does the split follow the light or the beer?

(hard for us to tell from the photo - but wow, never seen that before)

 

[gomb]

Looks to me like the krausen just hasnt crusted on that side yet. Is it uneven, maybe all the activity is keeping that area from crusting? Maybe the crust just hasnt formed on that area and its making its way there, you just happened to get a cool look? It appears to be starting to crust in the white area, i wouldnt worry about it, just enjoy having an oddity that alot of people havent seen.

 

[Diver165]

Maybe this is a sign....

This beer will be not HALF bad!

 

[Steven9026]

Hey, LOL, It's a black in tan recipe.. LOL...

 

[70Cuda383]

I went ahead and wrapped a blanket around the carboy anyway, hopefully if it was temp or light, either way the blanket will help to even that all out.

the light side of the cake is closer to the bathroom light. It's also closer to the heater, which is 5 feet away. we keep our house thermostat set to 66 degrees, but the basement can be quite a bit cooler, so I added a heater to the bathroom to try to stabilize the temps and keep it around 68.

never tilted the carboy after I set it in place and it started doing it's thing. there was some tilting and swirling around as I tried to spread the yeast around the wort, which proved to be a bit challenging with 5 gallons of liquid in a 6 gallon carboy, and a tiny 1.5" hole at the top!