Calling all math wizards

[phatuna]

Can you help me with the following? I have my gravity into fermenter, but am missing my pre-boil gravity:

5 gallons gravity = 1.044
6.25 gallons pre-boil gravity = ??

Thanks for your help and let me know if more data is required

 

[BarleyWater]

1.035............

 

[DNW]

No math required.

According to Beersmith it's 1.035

 

[DNW]

err, check that. He is asking what his pre boil, high gravity volume is, so it should be lower than the 5gal gravity.

d'oh! I reversed it.

 

[bernerbrau]

I get 1.034.

 

[BarleyWater]

Pretty easy to figure out since you're boiling off pure water which is 1.000.

44*5=220
220/6.25=35.2
1.0352 or 1.035

 

[phatuna]

That's great, thanks a lot guys!

 

[Rick500]

Another way to state BarleyWater's solution... same thing really:


5 gal / 6.25 gal = 0.8

0.8 * 44 = 35.2

... 1.0352

 

[PseudoChef]

M1v1 = M2v2

 

[ajf]

The above answers should all be true if you transferred everything from the kettle into the fermenter.
If you left 1 quart in the kettle when transferring to the fermenter, then you would have ended the boil with 5.25g, and the re-boil gravity would be 1 + (0.044 * 5.25 / 6.25) = 1.037

-a.

 

[TipsyDragon]

you could just use your recipe and figure out the pre-boil gravity from that. can't be that hard.

 

[uechikid]

This site rocks. So many so willing to help.:rockin:

 

[HOP-HEAD]

This site rocks. So many so willing to help.:rockin:

Ask the same math question on any other forum and see how many people jump up with an answer.... it's just that this place is loaded with a bunch of engineers and other technically minded folks. ....errrr, beer nerds.

 

[oldschool]

This site rocks. So many so willing to help.:rockin:

Until you piss everyone off like I did.

 

[phatuna]

you could just use your recipe and figure out the pre-boil gravity from that. can't be that hard.

There are a lot of variables when all grain brewing which contribute to pre-boil gravity which is called efficiency. So, gathering pre-boil gravity from my recipe is not possible. Unless of course my efficiency to kettle was so repeatable and predictable that I could just figure it out.. I'm not there yet, nor do I think I'll ever get to that point