Quick question re: pre boil vs post boil gravity

[scottvin]

I just finished a red rye brew and thought my pre and post boil gravities were close.

Pre 1.044 @ 6 gallons
Post 1.054 @ 4.75 gallons

Any thoughts?

 

[bajaedition]

things are going as plan, you see you concentrated your sugars by boiling off that water

 

[scottvin]

I understand that. Just seemed a little low compared to previous brews

 

[InLimbo]

What seemed low? The actual volume in the kettle? The difference between the OG and SG? Were you expecting a higher concentration/higher SG? Lower SG?

 

[Minky]

Divide the final wort volume by the starting volume: 4.75/6 = 0.79. Now multiply the ending gravity by this number: 0.79 X 54 = 42.7.

Looks like pretty normal figures for a 60 min. boil.

 

[scottvin]

Divide the final wort volume by the starting volume: 4.75/6 = 0.79. Now multiply the ending gravity by this number: 0.79 X 54 = 42.7.

Looks like pretty normal figures for a 60 min. boil.

the 42.7 was the pre-boil SG - correct?

 

[Minky]

the 42.7 was the pre-boil SG - correct?

That's right. When you do those calculations, use 54 instead of 1.054, and so 1.044 becomes 44. The 42.7 is very close to 44, so it looks like you're right about where you would expect to be given your pre-boil and post-boil volumes.

 

[Nashbrewer]

1.044 is 44*6 = 264 gravity points.
1.054 is 54*4.75= 256.5 gravity points.
One or multiple numbers are incorrect. I suspect volume measurements at some point. Could also be incorrect temperature when measuring.

 

[scottvin]

1.044 is 44*6 = 264 gravity points.
1.054 is 54*4.75= 256.5 gravity points.
One or multiple numbers are incorrect. I suspect volume measurements at some point. Could also be incorrect temperature when measuring.

I would go with volume measurements as they were somewhat approximated.