I recently forgot to take a reading before secondarying my Oatmeal Stout.
There was a small amount left in trub that I siphoned off.
I measured and its reading 1.030. Some of the trub has settled. Would that offset the reading?
As long as the hydrometer is floating clear and the ale is de-gassed, it will give a good reading.
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I usually (usually he says, twice really) get my hydrometer sample from filtering the trub. Just run it through a coffee filter. takes a while but you have time when you are bottling. Then I drink it