[Virwill]

Hi, all. Just brewed a partial extract IPA w/a mix of whole and pellet hops. All looked good except I didn't hit my original gravity, 1.066. Hydrometer reads 1.057; temp corrected, it's 1.059. I'm wondering if trub in the bottom of my sample tube could affect the reading. I poured the cooled wort through a sanitized strainer but took a sample before it settled, and there's about an inch of trub in the bottom. Could that affect my reading? 

[Pope of Dope]

It should not affect the reading. I've had instances where there was a lot of trub and this did affect the reading, despite general advice dictating that it should not.

[Bob357]

Unless the wort is saturated with break material and hop matter the reading should not be affected. If your hydrometer was sitting on a dense layer of trub in the sample tube the gravity would read high, not low.

[Virwill]

Thanks, gents. 

[denny]

Did you happen to do a partial boil and add top up water afterward?

[rburrelli]

Was that a pre or post boil gravity reading?

[Virwill]

Did you happen to do a partial boil and add top up water afterward?

Yep.

[Virwill]

Was that a pre or post boil gravity reading?

Post-boil, cooled.

[denny]

Did you happen to do a partial boil and add top up water afterward?

Yep.

Then that's likely the issue.  When you tool off, the wort is heavier than the water and sinks to the bottom.  When you take a reading you get the watered down wort on top.  Don't sweat it.