First pull smells funky

I noticed that if I leave beer in the lines for a couple of days without pulling a pint, it starts to smell bad, like sulfur farts bad... If I toss the first few sips then the beer comes out smelling like it should. My lines are inside my keezer, so they are being kept chilled at 40F so I don't think its temperature related. My first thought was maybe my lines need a cleaning. I have also noticed this with a different keg on a different set of lines once in the past. However, the thing that is throwing me off is that the lines I am using on this keg are brand new and were soaked in sanitizer. Any thoughts?

Ever see a bartender pull the first pint of the day? Fills the glass a bit...pours it out...then draws the pint.

my beer isn't funky on the first draw, but it is lower in carbonation. I toss the first couple ounces when i haven't poured a beer for days.

Yeah, pouring out the first draw seems to do the trick. However, it concerns me big time that the first draw smells like farts...

No one else has run into this problem???

You pour out the first draw, as in the entire amount of beer that's in the lines? That seems a little disheartening. With an 8' line, won't I be wasting a lot of beer if I have to empty it out once a day?

that's my thought. I just got a freezer a few weeks ago and I should have a keg ready for this weekend and I hope I don't run into this problem even though i've never read about it before/.

I had this happen on a PA that I made a while back. It kind of smelled like an old gym sock.

Needless to say, I drank that keg pretty darn quickly.
-Me

Yeah I ended up drinking that keg really quickly and haven't run into that problem again.

I had this happen to me once, but it was the whole brew, not just the first pull, this was caused by old yeast.

I wrote a post about it on my blog - Why home brew beer smells bad, how to prevent it

Apart from the yeast being off, it can even be sanitization issues.. are your pipes nice and clean? If you pull the first draw, does the smell go away?

Could it be buildup in your faucets? If you don't have forward sealing faucets, there's probably more of a chance of something funky growing in there.