Hydrometer reading question

[Bartman]

Does the thick viscosity of oatmeal affect the hydrometer reading or does it only measure the sugar?
The reason I ask and I didn't want to make this another stuck fermentation thread is, I brewed an oatmeal stout using 2lbs of flaked oats with an OG of 1.072 and after 2 weeks it is still at 1.032. Of course it is quite thick and that was what I wanted. I pitched it on a huge cake of S-04 I used on a brown IPA, so there was plenty of yeast to eat the sugar.

 

[ArcaneXor]

Hydrometers measure the density of a liquid relative to water - they don't discriminate between sugars, dextrins, or whatever else causes the liquid to be as dense as it is.

 

[kanzimonson]

They also only measure what's dissolved in the liquid. If there are proteins that are suspended, but not dissolved in, the wort, then they will not affect the reading.

 

[jeremyx]

Give it another week....