Pre Boil/Post Boil Gravity Oddity

[Piperlester]

Brewed a pale ale today (BIAB, but that is irrelevant to this question).

Pre-boil volume: 8.9g
Pre-boil gravity: 1.03

Post-boil volume: 6.2g
Post-boil gravity: 1.039

My question... does that seem a little odd? I have an temperature correcting refractometer, so temps shouldn't matter, but with the expected OG being closer to 1.047, I'm a little confused. Does that seem right? (I'm a bit too far into a the "sampling session" to do much more than add 15 minutes to the boil and post here. BrewersFriend says we're well short of what we should be at, even with the 6.2g remaining).

Thoughts?

Many thanks!

-Piperlester

 

[day_trippr]

I used those numbers two different ways to come up with an answer, and assuming the pre- and post-boil volumes and pre-boil gravity were accurate both methods point to a post-boil gravity of 1.043. Using that value, if you wanted to get to an actual post-boil gravity of 1.047 you'd need to get the post-boil volume down to 5.7 gallons...which doesn't seem unreasonable for volume to fermentor...

Cheers!

 

[Ozarks Mountain Brewery]

preboil readings are not always accurate, unless you have a small batch and can stir very well, I can get 3 or 4 different readings from my 12 gallon set up even after whirlpooling for 10 minutes

 

[Piperlester]

Thanks guys - I panicked for nothing, added 15 minutes to the boil and ended up around 5.75g and the hydrometer reading 1.05. Looks like all is well in beertopia.