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took a gravity reading today at the end of the transfer from the kettle and there was quite a bit of trub in the cylinder, like the whole flip'n tube. so would the trub hold the hydrometer up and give a false reading?

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It's explained pretty well here – twospeeder Mar 7 '13 at 22:46
up vote 3 down vote accepted

If the trub is actually physically holding the hydrometer up, preventing it from moving down, then unambiguously: yes, the trub will render your hydrometer reading useless.

If, on the other hand, the trub is suspended in the liquid, it is a mixed bag. Suspended solids will impact a hydrometer reading, but for brewers it is usually very minimal. The only actual measurements I've seen have put the effect at well below even a single point of gravity (thousandths digit on SG scale), though it is conceivable that the effect is more significant in very trub-heavy samples. Still, it's hard to imagine that we'd see an effect of more than a couple of points.

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agreed and with my experience I should know to wait for the trub to settle, but I kinda fell stupid having to leave asap. I came home after work (now) and got an "unobstructed" reading, and it was right where I needed to be. I always wait a day or two for answers but Plus one for now for sure! – Ryan Shdo Mar 8 '13 at 8:36
@Ryan Shdo - what was the difference between your trubbed reading and your unobstructed reading? – mdma Mar 8 '13 at 21:43

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