How does Yeast affect Hydro Readings?

Just wondering as with last nights btach I added my Yeast, then I remembered that I needed to take a Hydro reading. I took one before I aggitated the Carboy. I'm sure that it'll affect the reading, but I don't think by much. What do you think?

It will not change it unless it's started fermenting.
Particulates to not change the density of a liquid if it does not impede the hydrometer.

Sweet. Thanks for the info Orfy.

Yeast are heavier than wort or beer (wouldn't flocculate otherwise), but the effect is small to the point of being meaningless. Bubbles coming out of the brew and attaching to the hydrometer can be a problem.

That's simple enough to take care of though. When you put your hydrometer in your sample, give it a hearty spin. This will dislodge any bubbles that might be clinging to the hydro. Once is stops spinning (usually only a second or two) take your reading. Also, if your sample has been sitting for a couple of minutes with the hydrometer in it you'll want to perform the same procedure.

The yeast cells themselves won't affect the reading.