Originally Posted by pkeeler
Your hydrometer could be wrong, you could check it. Another possibility is that you collected less than 4 gal. I don't know if it is possible to get 95%, but I agree with you that it is unusual. I've heard on these forums that when wort sits after lautering it can stratify into different SGs at different depths. So, if you didn't stir well before drawing your sample, it is possible you got an unrepresentative sample. You will find out post boil.
Only one way to find out about the hydrometer - in fact I should have tested the damn thing in 20c water before ranting about it possibly being at fault
interesting remark about strata generating in the wort - thing is I set the sample aside in a glass and then the following morning tipped that into the hydrometer tube, so it was thoroughly re-agitated at point I took the reading.
I collected 4 gallons (a smidgeon under 15 litres to be exact). I always make a point post-lauter of dumping collected wort into my (marked) bottling bucket for volume measurement.
maybe I just need to accept my fate and take my place in the holy trinity