hydro math

[anthonyadams]

what is the math to go from an og to a fg

 

[superjunior]

not sure I understand the question. the og is your original gravity before the yeast is pitched. the fg is the final gravity after fermentation is complete. the MATH is the og-fg x 131.25 = your abv

 

[ACbrewer]

subtraction... So a first measure of 1.040 (og) then a 1.010 (fg) would give you a difference of .030

But I sense there iss omething more to your question there.

 

[anthonyadams]

thanks is there a formula for what the fg should be?

 

[honeybadger]

FG depends on your OG and attenuation. Attenuation depends on yeast type and mash profile. Usually attenuation is 70 - 75%.

 

[anthonyadams]

ok so og X .75 = fg ?

 

[Ace_Club]

ok so og X .75 = fg ?

It depends on the attenuation of the yeast strain. It can range from the high sixties to the low eighties.

 

[ACbrewer]

yeah well sort of -if 75% of the sugar is used, then only 25% remains so I use usually OGx.25=FG, it varies with your yeast - you can look it up on the manufacturs website. I use the 75% as the attenuation as my rule of thumb. If I'm close to 75% I figure I'm just about fermented, but if I'm like 50% then I figure I should go some more.

 

[ThePearsonFam]

You can forecast what your FG range will be by multiplying the OG points by the lowest and highest attenuations of the yeast you're using...

ex) 1055 beer with White Labs WLP001 California Ale Yeast pitched. The attenuation range that should be achieved by that yeast is 73% - 80%. Now, the math...

55 * .73 (lowest attenuation)= 40 points that get attenuated... 55-40=15, or FG will be 1015
55 * .80 (highest attenuation)= 44... 55-44=11, or FG will be 1011

The expected range of FGs is ~ 1011-1015. That's simply based on the available sugars and attenuation. Mash profiles and many other factors will influence the FG as well.

 

[Caboose]

You can forecast what your FG range will be by multiplying the OG points by the lowest and highest attenuations of the yeast you're using...

ex) 1055 beer with White Labs WLP001 California Ale Yeast pitched. The attenuation range that should be achieved by that yeast is 73% - 80%. Now, the math...

55 * .73 (lowest attenuation)= 40 points that get attenuated... 55-40=15, or FG will be 1015
55 * .80 (highest attenuation)= 44... 55-44=11, or FG will be 1011

The expected range of FGs is ~ 1011-1015. That's simply based on the available sugars and attenuation. Mash profiles and many other factors will influence the FG as well.

Thanks for posting that, I would say that is the most simple explanation of the process I have found yet!

 

[ThePearsonFam]

I'm glad it helped!