Measuring OG

[NeilArge]

G'day all
This has been touched on in different places in this forum but nothing really addresses the issue I want to get your wisdom on...
So, yesterday I made a Sorachi Ace saison, aiming for 22 litres into the fermenter at OG 1.062 at 80% brewhouse efficiency. Did a 3 step temp mash and that all seemed to go well. Lautered and sparged slowly. 29 litres into the keggle, but got a disappointing SG reading (temp. adjusted) of 1.044. Anyway, keep going I thinks. Then follows a 90 minute rolling boil. Ran 22 litres into the fermenter at OG 1.054. That last reading was taken of some clear wort left behind in the keggle (c. 20C). I ran out of time to clean the keggle up last night but went out this morning and saw, not surprisingly, that there was quite a bit of clear wort on top of the trub. Poured this gently into the hydrometer tube: OG 1.058! So, I guess my question is: when is the best time/stage to take an OG reading? I have found such a wide variance in OG readings from taking one 'midsteam' from the keggle to the fermenter to wort left behind in the keggle.
Cheers
ToG

 

[Online Brewing Supplies]

I do on the run gravity readings during the process to gauge efficiency but always take my OG from the fermenter before pitching.
Nev

 

[DJ_L3ThAL]

Not sure if its the best time but I usually whirlpool and right before I remove the mash paddle im stirring the whirlpool with I stick in my sample tube and suck it from the centre of the whirlpool where I figure its got the best mixing of the wort.

Letting it sit and stratify might not be accurate although physics would suggest you'd have a lower concentration at the top of the fluid where you mention it was 1.058 and clear.

In any case id be taking the reading between as soon as the boil is completed and when you are filling the cube/fermenter, so that you have the full wort volume as one and are measuring the mixture as a whole.

 

[bundy]

Unless using a refractometer have you considered cooling your samples to 20 degrees when measuring? I've read temp adjusted samples are notoriously unreliable. I personally take the sample (like Nev many times throughout the process, end of mash, end of boil, at pitching) any samples taken on the hot side I throw it in the fridge till it cools, then measure the gravity. A small sample doesn't take long to cool and at least you know your reading is taken at the right temp.

That would possibly explain big discrepancies especially post mash, post boil etc.

The other thing I've been told is even take 2 or 3 samples and get an average as often 1 sample may be wrong.

 

[NeilArge]

Unless using a refractometer have you considered cooling your samples to 20 degrees when measuring? I've read temp adjusted samples are notoriously unreliable. I personally take the sample (like Nev many times throughout the process, end of mash, end of boil, at pitching) any samples taken on the hot side I throw it in the fridge till it cools, then measure the gravity. A small sample doesn't take long to cool and at least you know your reading is taken at the right temp.

That would possibly explain big discrepancies especially post mash, post boil etc.

The other thing I've been told is even take 2 or 3 samples and get an average as often 1 sample may be wrong.

Thanks for the advice. I do refrigerate the hydrometer sample (with a thermometer in it) to get the right reading rather than rely on the various software tools. But you've all taught me the importance of taking multiple readings. I'll also lash out and buy some distilled water and calibrate my old hydrometer.
Thanks heaps,
ToG